I
The stone that has been used exclusively hitherto in Munich for printing is a stratified limestone, found in the territory from Dietfurt to Pappenheim, and along the Danube down to Kellheim; hence the name Kellheimer plates, presumably because in past times the stone was quarried there first, or else found in its best quality. Now the Kellheimer quarry is exhausted, and the trade in the stones has transferred itself to Solenhofen, a village in the judicial district of Mannheim, three hours distant from Neuberg-on-the-Danube. All the inhabitants of Solenhofen are quarrymen, and the entire surrounding country seems to have a surplus of the stone, so that even with the greatest demand no scarcity is to be feared for centuries.
When the upper layer of earth is removed to the depth of six to ten feet in Solenhofen, the stones are found in strata lying horizontally on each other. First come strata of brittle stone, which often are composed of hundreds of plates as thin as paper. With proper care, each plate can be loosened and lifted whole. These layers are useless, being too brittle, and yet being too firm and not white enough to permit their possible use as chalk.
The Solenhofen stone consists chemically mostly of lime earth and carbonate. It is almost wholly soluble in nitric and other acids, the carbonate being liberated in gaseous form and disappearing. Since the various kinds of marble have almost the same component parts, one might suppose that marble should be available for lithography. But the many dark, uneven colors of marble and chiefly the many cracks and veins make considerable difficulty. However, I have found many evenly colored greenish, gray, bluish, and brownish Bavarian and Tyrolean marbles very useful for some methods, especially because of their superior hardness. Still, the Solenhofen stone will retain the advantage because of its light color and its greater cheapness.
The white Parian or Carrara marble is still lighter in color, to be sure, and really is rather useful for pen and crayon work. But though in part it is harder, on the whole it is much more porous and not so finely grained as the Solenhofen stone, and therefore not at all available for the intaglio method.
Since lithography began to arouse general interest, there have been attempts to find a stone similar to the Solenhofen, and there has been some fair success in France, Italy, England, and lately in the Kingdom of Prussia. With the enormous masses of limestone which cover the surface of the earth, it is not unlikely that this stone will be found in many places, either in layers of plates one, two, or more inches thick, or in great blocks which can be cut into plates.
In the Solenhofen stones one layer is not as good as another, and even in the same layer there may be a decided difference. Therefore, if one would produce perfectly beautiful work, it is necessary to obtain selected and perfect stones. This should be stipulated beforehand with the quarrymen, who now know pretty well how the best stones should be constituted.
A good stone must have the following properties:—
(1) The proper thickness. Thickness must be proportionate to the size. Smaller plates will resist the pressure of printing even if they are not so thick as the larger ones must be. But it is best to buy no stone less than one and one half or more than three and one half inches thick, because the thinner ones will not bear frequent grinding and the thicker ones are too heavy and inconvenient, besides taking up too much room. The best thickness of a stone is two to two and one half inches.
(2) Good mass. There are soft and hard stones. Sometimes the same stone is hard above and soft underneath, or the reverse. Often, also, a stone may consist of several thin and unequal layers. In the latter case, if the union is good and the layers are not easily separated, it will make no difference, so long as the stone is good in other respects. On the whole, however, it may be assumed that the harder stones are the best for all methods, so long as their mass is entirely uniform and they are not marred, as is the case with many, with white dots and patches. Then, to be sure, they are not worth much for any process, and at best can be used only for pen designs or for such of the intaglio processes where the lines need no particular sharpness. Such stones, generally gray, very hard, with softer, somewhat lighter patches or specks, are very hard to grind evenly because the softer parts are most powerfully attacked by the grinding material and become depressed. This produces the following defects:—
(a) In pen work, the pen will catch often, whenever it comes to such a place. This, however, is not so important: but
(b) In the crayon method there will be defects and lights in the shadings on the softer places, which are very hard to correct.
(c) In the etched or engraved methods, the needle will sink in much deeper when it passes over such softer spots, making a deeper and broader line which injures the clearness of the drawing. In etching, also, the softer places are more affected by the acid; and it is better, therefore, to use a soft stone whose entire surface is uniform, than to have a stone that is hard but uneven.
A very soft stone cracks easily in the press, unless it consists of several layers, the lower of which are hard. But it is easier to engrave, and as a rule gives blacker impressions, because it sucks more color in, and holds it because of its greater porosity. Printing, however, is somewhat more difficult, because these stones take dirt readily; nor is it possible to get so many impressions. They are not useful for crayon work because the finest shadings are too easily etched away; and pen work is difficult on them, because the steel pen easily cuts into the stone, fills its point with fine dust, and thus gives no ink flow. This softest stone in Solenhofen generally looks yellow, or is marbled with red and white or has many yellow veins.
Even those stones whose uniformity, thickness, and hardness make them best for all methods, often have defects, such as so-called glass spots or tiny, sometimes invisible holes, broad veins and cracks. All these must be avoided when selecting stone. Very small deep veins, which often are fine as hairs, yellowish and grayish spots, impressions of fossil plants and fishes, etc., are not harmful. It is rare to find a stone as large as a sheet of note-paper that is entirely free from these little defects.
(3) The form of the stones also is to be considered, and must be selected according to need. To be sure, a small design can be drawn on a large stone; but apart from the inconvenience, the construction of the press demands that the stone be not much larger than the drawing. However, at the end where the impression begins and stops, there must be at least an inch margin to give sufficient room for the roller to take hold, as will be explained more particularly later.
When one has to print small things like visiting-cards, etc., it will not be profitable to use large stones, especially if they are to be saved for future use. Small stones of the size of an octavo sheet are better. Therefore it will be wise to have stones cut to various sizes in the beginning. It would be well also that one of the printers, or the polisher, strive to attain skill in cutting stones to size. Sometimes polishing discloses defects in a stone, making it useless for a design of any size. But it is possible to cut it up into many small ones that are perfect. Sometimes a stone cracks under the press or breaks through accident. Skill in cutting will enable one to make small and good stones out of the pieces.
It is essential for good work in the press that the stones be cut very true. The stones that are used for flooring in churches, etc., usually are cut so that the upper face is larger than the lower. This is done to make them set better in the mortar and to enable the stone-cutters to fit them closely together on the top. But this must not be done with stones for printing, because such stones could not be tightened properly in the press and would lift during the printing. Printing-stones must be cut absolutely true vertically. Indeed, in work where several plates are to be used to make one complete impression, and where steel guide-points in the frame are used instead of laying the paper on the plate, it is beneficial to cut the stones conically, so that the base is one fourth inch greater than the top. The plate can be tightened better and is less likely to be moved from its place during the impressions.
Despite their hardness the stones are brittle, and a single light but sudden blow with any hard body, such as a steel tool, may cause a crack in the thickest stone. It is necessary to exercise great care to avoid all shocks.
This property of the stone is used in Solenhofen to cut the stones according to desire. A small hammer of hard steel, weighing scarcely two ounces, is used. Its end is somewhat like a stone-chisel, but not nearly so sharp. With this hammer, which is set on a thin handle two or three feet long, the workman strikes light but very swift blows along the line of desired cleavage, each tap being about an inch from the preceding one. The stone is so laid that its greater part is free, resting on nothing. This light operation is sufficient to cleave the largest stones.
The cleavage is not always uniform and true. Therefore the stone usually is finished with a sharp stone-chisel. It is possible also to divide a stone as desired by supporting it at both ends so that there is nothing under the part to be split, and then cutting along the line with a chisel of hardened steel, not too sharp, which is tapped lightly with a light hammer. The varying sound tells at once when the stone cracks, and then a few light taps with the hammer on the other side suffice to separate it. Before one attains the necessary skill, however, he will smash many a stone. Therefore it is not advisable to try this on a stone that has a design on it, for a single incorrect or over-heavy blow often will split the stone in the wrong direction. Blows that are too light, on the other hand, often make it almost impossible in the end to cause a cleavage along the desired lines.
II
POLISHING
The stone plates that come from Solenhofen, even if polished according to stipulations, rarely are available for printing, but must be specially polished by one who understands the work thoroughly.
The first requisite for this is a straightedge of iron or brass, as true as possible. This ruler must be laid on the stone in various directions, and the lithographer must note all parts where there is space between the straightedge and the stone. The greater the space, the greater the unevenness of the stone; and those that show especial unevenness should be set aside from those that have little.
When this has been done, the very uneven stones must be ground with a coarse sandstone and plenty of water applied to the elevated places till the straightedge can be applied in all directions without showing any material interstices. Then these ground stones may be placed with the others that were fairly even in the beginning.
Now we take one of these stones, and lay it on a strong, firm table, the best being one to be described later. Finely grained sand is sprinkled over its surface. In the absence of sand, a substitute can be made by powdering a common sandstone of the kind used for coarse grindstones. A spoonful of water is poured over this. A little soap may be mixed with the sand. It facilitates the grinding and makes the sand take hold of the stone better. Now another stone is laid on the first one, and is moved back and forth continually in all directions. The sand and water must be renewed often. Thus both stones, the upper and lower, will be ground simultaneously, and very evenly and true, if the work is done right.
One must take care never to draw the upper stone far beyond the lower one, because that would throw the centre of gravity of the upper plate too near its ends, as a result of which the upper plate would become concave and the lower plate convex. To avoid this defect, the upper plate should be moved around only in small circles. It is good also to change the plates around frequently, so that the upper shall be the lower. Another good plan is not to use two stones of equal size, but to take for the upper stone one only half as large as the lower. It is necessary also that the straightedge be applied frequently. The stone must always be cleansed thoroughly before this test.
Once one has the proper experience, it is possible to tell by mere touch if the plates have been sufficiently ground. So long as they still have uneven spots, a certain resistance is noticeable, so strongly sometimes that it is impossible to move the upper plate further without lifting it and sprinkling new sand. Sometimes this friction is so great that manual strength does not suffice to separate the stones, especially if they happen to dry. If tools are used to separate them, it happens often that pieces are torn from the stones, because they adhere so mightily. In this case a very simple and convenient remedy is the best. An ordinary table-knife is inserted gently and then tapped very lightly, when the stones will separate at once.
Whenever sand is applied, water must be applied also, but not too much, as in that case it would only wash away the sand. Here, too, practice must teach the exact proportions.
From the stone-cutter's work, as well as from the primary grinding with sandstone, the plates will have visible furrows and scratches made by the coarser grains of sand. Under the polishing all these disappear bit by bit, and there appears a fine grain, consisting entirely of fine dots; and this is the finer in proportion as the sand is crushed by the process of polishing and also according as less fresh sand has been used.
When the marks of the sand have vanished completely, it is fairly certain that the stones are polished sufficiently. To make sure, the straightedge can be applied again. It must not be imagined, however, that it is necessary or possible to polish a plate so perfectly that there will be absolutely no spaces between any part of its surface and the straightedge. A perfect and mathematically level plane surface is hardly likely ever to be produced. If the stone is almost level, and the unevennesses do not exceed the thickness of letter-paper, it is quite sufficient.
Although this sort of polishing, with two plates at once, is not used in all lithographies, some preferring to polish with small pieces of sandstone, I give it here as the best, because it demands little skill and is quicker, so that one can grind off four stones in the time required for one under other methods.
In this matter of smoothness of the stone it is impossible to be too careful. The beauty of the imprint depends upon it. Errors in the polishing cause great trouble afterward. Therefore the manager of a lithography must pay close attention to this work. In the Lithographic Institute in Berlin the rule has been adopted that no engraver shall accept a plate that he has not found thoroughly good, under penalty of reimbursing the printers for all extra trouble and work.
This first polishing, however, is only the general preparation of the stone. Afterward they must be polished and prepared especially for each particular method, as will be explained in the proper place.
III
SORTING AND STORING
When the plates have been polished, they are cleansed with water and sorted for their various uses. Now it is easier to see just what quality the stones have, their defects, and consequently, what work they are best for. Those not uniform are best for coarse pen work. Those of uneven coloring, but hard and thick mass, can be used for the finer pen drawings, for etching and engraving, or for transfer work. For crayon work the clearest and most evenly colored stones of extreme hardness are to be selected.
They can be stored anywhere that is not too damp and not too much exposed to winter cold. Dry cold does not hurt them; but if they are wet through and through and then freeze, they will crack. In constant dampness, too, saltpetre and other salts enter them and they crumble. In clean water they do not undergo any changes.
I will describe the storage of etched and designed stones later.
If the stones are to be used after being stored in any damp place, they should be kept for several days in a temperate and dry place till they have dried thoroughly, as otherwise they are not easy to work in any style. This is not necessary if their place of storage has been perfectly dry.
[CHAPTER II]
OF INK, CRAYON, ETCHING, AND COLOR
I
CHEMICAL INK
The first and most necessary material in a stone printery is the so-called chemical ink, which would better be named fatty or alkaline ink, since it is a mixture of fatty and resinous materials with alkali. It is used partly to write or draw directly on the stone, partly to cover the stone as with an etching surface, and partly to transfer to the stone from paper.
The purpose of this ink is, first, to cause a mass of oily, fatty substances to soak into the pores of the stone and also make certain portions of its surface fatty; and secondly, to resist acids according to requirement in such degree that the stone shall remain fat where needed, that thus the design, applied with this ink, shall be left untouched by acid.
I have remarked before that countless different mixtures can be made, most of which fulfill the purpose. But there enters the consideration that it must be an ink easy to use, that handsome work may be done by the artists with perfect ease.
Various mixtures answer this purpose very well, and I have found sometimes that men could work better with mixtures made by themselves than they could with those that I used for my own work. Perhaps this was a matter of imagination, or the real reason lay in the pen-cutting, it being well known that one man can use a pen that is absolutely worthless for another.
I myself have tested the values of some mixtures so thoroughly that I can declare almost positively that it will not be easy to find better ones for any purposes. I will describe these fully.
First of all, stone-ink is divided into two great classes. One is thicker, being used for drawing on stone. The other is more fluid, being used for transfers.
The following mixtures of the first kind are the best:—
| (1) | White Wax | 8 | parts |
| Soap | 2 | parts | |
| Lampblack | 1 | part |
This ink does not really serve for writing or drawing on the stone, but is used mostly for coating those places that are to be protected from the etching fluid. If this ink is needed in a thickened form, the wax should be heated in an iron pan till it burns and the combustion should continue till one half of it is consumed. The longer it burns, the harder will be the remnant.
| (2) | White Wax | 12 | parts |
| Tallow (Ox Fats) | 4 | parts | |
| Soap | 4 | parts | |
| Lampblack | 1 | part | |
| (3) | Wax | 12 | parts |
| Shellac | 4 | parts | |
| Soap | 4 | parts | |
| Lampblack | 1 | part | |
| (4) | Tallow | 8 | parts |
| Shellac | 8 | parts | |
| Soap | 4 | parts | |
| Lampblack | 1 | part | |
| (5) | Wax | 8 | parts |
| Shellac | 4 | parts | |
| Mastic | 4 | parts | |
| Soap | 4 | parts | |
| Lampblack | 1 | part | |
| (6) | Wax | 8 | parts |
| Tallow | 4 | parts | |
| Shellac | 4 | parts | |
| Soap | 4 | parts | |
| Lampblack | 1 | part | |
| (7) | Wax and Gum quajak | 12 | parts |
| Tallow | 4 | parts | |
| Soap | 4 | parts | |
| Lampbblack | 1 | part |
The wax and gum are melted in equal proportions, the undissolved portion is discarded and of the mixture twelve parts is used as above.
| (8) | Wax | 6 | parts |
| Shellac | 4 | parts | |
| Tallow | 2 | parts | |
| Mastic | 3 | parts | |
| Venetian turpentine | 1 | part | |
| Soap | 4 | parts | |
| Lampblack | 1 | part |
There is no important difference between the inks in the seven last formulas. Those that contain shellac remain fluid a little longer but are harder to prepare. It is not necessary to be painfully minute about the proportions of the various materials, providing the proportions of soap and lampblack be correct. The soap is about one fifth and the lampblack about one twentieth part of the whole. If too much soap is used, the ink will dissolve more readily, but the solution will become slimy more quickly. Too much lampblack would make the ink run.
MAKING THE CHEMICAL INK
In making any of the inks mentioned, first divide the required quantity of soap into two equal parts. Put one part into an iron pan with the other substances, and heat till the mass begins to burn. Let it burn till almost one half is consumed. Then cover the pan with an iron lid, or place it very carefully into a basin of water to extinguish and cool the mixture.
One part of the soap is mixed in at once, that the combustion may make it mix well with the other substances. But it loses some of its strength and sates itself with carbonic acid, so that it is not quite so powerful as before to attack the fats. Therefore a second part is added after the combustion. Then the complete mixture is heated again, but only to a degree sufficient to melt the soap.
Now take up a bit of the mass with a clean knife and see if it is easily soluble in river or rain water. If the soap was good (something not always the case), the quantity named in the formulas always suffices. If it does not contain enough alkali, little pieces of soap must be added till the mass is soluble. Then the lampblack is added while the mass is being stirred without cessation.
The lampblack must be of the finest sort, and should be roasted and burned in a closed vessel until it ceases to give off any yellow smoke.
When everything has been stirred till the mass is nearly cold, it is kneaded into any desired shape, sticks being the best, and so saved for use.
The following remarks are to be noted especially:—
(1) The soap is to be the ordinary soap made from ox fat and lye. In the formulas its weight is calculated in fresh form, which, of course, includes considerable water. If the soap is very dry, less must be used.
Venetian or vegetable oil soap is not so good because the ink easily becomes slimy afterward when dissolved in water. It does not resist acids so well, either. If, however, the other kind is not to be had, or to be had only in poor quality, the Venetian soap will do. It will be necessary merely to make frequent fresh solutions in water of the ink.
(2) Lampblack is not the only substance available for giving color to the ink. Vermilion, red chalk, indigo, blue lake of logwood, and several other colors can be used, so long as they do not consist of acids or other salts, and thus have properties that could alter the nature of the soap. The finer kinds of ordinary lampblack can be used without burning, but then a part of the soap always is rendered inactive, because the lampblack usually contains a considerable quantity of inflammable wood acid which unites with the alkali, neutralizes it, and thus destroys its effectiveness against fats. Therefore, if it is not roasted beforehand, it may be necessary to mix more soap with the ink after it is made, and this does not completely remedy the trouble. Lampblack can be purified by rubbing down with strong lye and then boiling in sufficient water till no trace of alkali remains, if roasting and burning be undesirable for any reason.
Better even than this purified lampblack is one that one makes for himself from ox or other animal fat, from wax, or better still, from a mixture of ox fat and resin. The fat is melted and poured into an earthen lamp similar to those used for city lighting, with a cotton wick. The lamp is lit and placed under a plate of iron or brass, so that the smoke must settle on it. The plate must be close to the flame. The soot is scraped off from time to time and dropped into a glass, which is kept covered. This process continues, the lamp being refilled till one has the desired quantity. This soot is very fine and bland, and so good that one can do more with an ounce of it than with three ounces of the ordinary kind. The ink made from it is extraordinarily fine and good.
It is to be noted in conclusion that the more soot is used, the blacker will be the ink, but the coarser will be the work, because the ink will have the tendency to spread. The less soot is used, the finer will be the work; but it is not easy then to see what one is doing or to judge if the design is strong enough. The quantities given in the formulas appear to me to be the best, especially if the self-manufactured soot is used.
(3) To dissolve the ink, rain water or pure soft river water is best. The rain water must not be very old or stale, otherwise the solution will get slimy.
(4) The severe combustion is not vital for making the ink, but helps very much in making it easy to use.
(5) When shellac is part of the mixture, it is vital to burn the mass well, as only thus will shellac dissolve properly.
Shellac, which is made in China and East India from an insect belonging to the bee family, will melt under moderate heat, but will not dissolve in any animal fat or oil unless it has previously lost its inherent acid, which occurs only under combustion. If shellac is melted with oil or fat, it covers the bottom of the vessel in the beginning. With heat increased till it causes combustion, it begins to swell, rises to the surface, and at last covers the surface in the form of a spongy mass. If the heat still increases, it begins to dissolve into foam. Then it is time to remove the mass from the fire and to cover it with a tight lid, that the flame may be extinguished.
If shellac has been once melted and has hardened, it dissolves only slowly even under severe combustion. It is better, therefore, to bring the other substances to combustion first, and then to mix the shellac in small portions, which will dissolve much more readily because they will be attacked by the great heat in the moment of melting and will not have time to swell first and get hard.
As soon as the mass has cooled a little, the second part of soap is added, and the whole heated, without burning, merely enough to melt the soap.
(6) None of these mixtures can be kept well any length of time in fluid form, that is, dissolved in water, because it becomes slimy after a very few days, sometimes sooner. It can be liquefied again by mixing with water, but not without affecting its durability. Therefore the ink must be stored dry, in which form it lasts for years without change. When required, a small quantity, about the size of two peas, is rubbed down in a very clean small earthen or porcelain vessel, such as a saucer. Those mixtures that contain tallow rub the easiest. The others, containing harder substances, require more pressure. The ink should be spread evenly over the bottom of the vessel. Then a coffee-spoonful of rain or other soft water is poured in, and the mixture is rubbed with the finger till the solution is perfect. Then it is put into a small, very clean pot of glass or porcelain and is ready for use.
(7) A great deal depends on the proper quantity of water. A good ink must be completely dissolved, with no solid particles left. It should be about as fluid as a good, fat milk or vegetable oil. If it is too thick, it makes the work difficult. If it is too thin, it will not withstand the etching fluid. A few experiments will teach the proper proportions. Even a good ink will make poor lines if it is laid on too thinly and not firmly enough. This, however, is due to the artist's lack of skill or to defective pens, of which I will treat hereafter.
With this quantity of ink it is possible to work for a whole day. Thus each day fresh ink can be mixed; and it is to be noted that the vessels must be cleansed scrupulously that no trace of the previous day's ink be left in them. The ink will dry during the work, and as soon as this begins to interfere with its use, one or two drops of water will thin it again sufficiently.
This is about all that need be said about the chemical fatty or alkaline stone-ink in general. Particular remarks will be found in the description of its use for particular methods.
II
HARD BORAX INK
Besides the inks described, it is well to make the following and keep it in stock for uses whose great value will be explained later.
| Shellac | 4 | parts | |
| Borax | 1 | part | |
| Water | 16 | parts |
Borax and shellac must be put into a clean pot filled two thirds with water and boiled for an hour. As the water boils away it must be replaced. When the shellac has been mostly dissolved, the mass is removed from the fire, cooled, and filtered through a clean cloth to separate the undissolved portions of the shellac.
This solution can be kept for years in a tightly closed glass. To color it, a portion is to be cooked in a copper or iron ladle till it is thick as honey. Fine lampblack or vermilion is stirred in till the mass is thoroughly united. Then water is added, and the composition boiled again till it is a perfect solution. This black or red ink is first-class and can be kept well in tightly closed glass.
III
FLUID INK
Herr Andre, in Offenbach, uses an ink which has the useful property of remaining good for years in fluid form. I do not find it so good for the very finest work as those I have described, but for music and script it is excellent. It consists of:—
| 12 | parts shellac |
| 4 | parts mastic |
| 1 | part pure ox-fat soap |
| 1 | part purified crystallized soda |
| 1 | part lampblack |
This is mixed with water and boiled in a clean vessel, being constantly stirred till it is dissolved. Then the boiling is continued till the water has disappeared almost entirely. Fresh water is added and the boiling continued till everything has dissolved anew. Then the mixture is filtered through a cloth and kept in a vessel where it is secure against dust. If it is seen on cooling that it is too thick it can be thinned easily with water. Also, when it dries during use it can be liquefied by adding water, unless dust has entered it.
IV
TRANSFER INK
All the above-named inks are intended for use directly on stone. If it is desired to write on paper and transfer this writing to the stone, those inks mostly prove too hard, unless one would use warmed stones, as described later. This, however, makes added work: therefore, I give here the recipe for an ink excellent for cold transfers.
| Shellac | 3 parts |
| Wax | 1 part |
| Tallow | 6 parts |
| Mastic | 5 parts |
| Soap | 4 parts |
| Lampblack | 1 part |
The mode of preparation is exactly like that of the rest. The mass can be kept only in dried form, not mixed with water. The evidence that this ink is good for transfer work is that, after it has stood for some days, it still manifests stickiness when touched with the finger. If the ink does not transfer well to the stone under moderate pressure, it is too hard, and can be improved by mixing in a little butter or vegetable oil, but it is necessary to dissolve the whole mass again over the fire. If the design squashes under pressure, the ink is too soft. It is necessary to consider the temperature of the place where it is kept, and even the time of year, in order to produce the proper consistency of ink for the best transfer work.
V
HARD ETCHING GROUND
Certain methods of stone-printing demand, besides the ink, a fatty, acid-resisting mass to coat the plates. It is either the same as the material used by copper-plate etchers, or, at least, is very similar to it.
Etching Ground for stone is as follows:—
| Wax | 12 | parts |
| Mastic | 6 | parts |
| Asphalt | 4 | parts |
| Resin | 2 | parts |
| Tallow | 1 | part |
This is melted in an iron pan over a fire hot enough to melt the asphalt perfectly. Combustion is allowed to ensue till a third of the mixture has been consumed. When thoroughly cooled, it may be shaped in any desired form and saved for use.
A good surface is made also by common wax, boiled and burned till almost five parts of it have been consumed.
VI
SOFT ETCHING GROUND
For some processes there is needed an etching ground which has the property of not coating the entire surface, permitting the etching fluid to penetrate at many spots uniformly, or, if it resists the etching fluid, still so easily affected by manipulation that it will admit the acid according to such manipulation. There are two ways to make it.
| (1) | Thick linseed oil varnish | 1 | part |
| Tallow | 2 | parts | |
| (2) | Wax | 1 | part |
| Tallow | 5 | parts | |
| Linseed oil varnish | 3 | parts |
The application will be described in the instructions about aquatints, etc.
VII
ACID PROOF INK
So I name a color which has the property of resisting acid when the stone is inked with it. It is useful in many cases, and even necessary. It is well, therefore, to make a supply of it.
| 2 | parts thick linseed oil varnish |
| 4 | parts tallow |
| 1 | part Venetian turpentine |
| 1 | part wax |
All must be well melted, mixed with four parts lampblack, well rubbed down and kept in a closed tin vessel.
VIII
CRAYON
Chemical or fatty crayon is a composition intended to be used on the stone plate in dry form like Spanish or Parisian chalk. The inks described previously have the property of soaking into the stone and making it greasy where applied. The same happens if they are applied dry, the degree of their penetration and adherence merely being less.
The mixtures that may be used to make crayons are countless. Wax and soaps, however, are better than resinous materials. Therefore it is likely that the compositions here named will be pretty nearly the best.
| (1) | Wax | 4 | parts |
| Soap | 6 | parts | |
| Lampblack | 2 | parts, roasted, or better still, made as explained before. |
The wax and soap are melted together. The lampblack is added then. All is rubbed down fine on a hot plate, and then placed on the fire again till it is fluid once more. Then it is poured on a stone plate coated with a little oil, so that it forms a cake of about one eighth inch thickness. When this has cooled a little, it is cut into thin pieces and put away till needed.
| (2) | Wax | 8 | parts |
| Soap | 4 | parts | |
| Lampblack | 2 | parts |
Burn the wax till one half is consumed, then melt the soap with it, and treat the mixture as before.
| (3) | Wax | 4 | parts |
| Spermaceti | 4 | parts | |
| Soap | 4 | parts | |
| Lampblack | 2 | parts |
The first three materials are melted together, the lampblack is added, and then the whole is treated as before.
| (4) | Wax | 8 | parts |
| Spermaceti | 4 | parts | |
| Soap | 4 | parts | |
| Lampblack | 2 | parts |
The wax is to be half burned away, then the spermaceti and soap are to be melted into it, and the whole treated as the other formulas.
| (5) | Shellac | 4 | parts |
| Wax | 8 | parts | |
| Soap | 5 | parts | |
| Lampblack | 3 | parts |
The shellac is to be completely dissolved with the wax by means of combustion after which the rest of the treatment is the same as before.
| (6) | Shellac | 4 | parts |
| Wax | 8 | parts | |
| Tallow | 2 | parts | |
| Soap | 5 | parts | |
| Lampblack | 3 | parts |
The same treatment, except that the tallow is to be mixed in after the shellac has dissolved. This crayon is a little softer than the others. The same is true of the following two.
| (7) | Wax | 8 | parts |
| Tallow | 4 | parts | |
| Soap | 6 | parts | |
| Lampblack | 3 | parts |
Wax, tallow, and soap are melted together and burned till one third of the mass has been consumed. Then the lampblack is added and the rest of the process is as before.
| (8) | Wax | 2 | parts |
| Tallow | 6 | parts | |
| Mennig | 2 | parts | |
| Lampblack | 2 | parts |
Wax, mennig, and lampblack are heated and constantly stirred till the mennig dissolves in froth and changes from red to brown. Then the lampblack is rubbed in thoroughly, the whole warmed again properly and shaped into sticks.
These are the best compositions, thoroughly tested by me, and it is very good to make a stock of all or most of them. In the case of the recipes for chemical ink, the differences are not great, and it is largely a matter of taste as to which kind one may use. But in the case of the crayons, each of them produces a different grain which creates a particular effect; so that by using various kinds of crayon one will gain greater perfection of work, or, at least, find execution easier than with only one crayon. Also, they are in proportion to the greater or lesser roughness of the stones; and the darker shadings are easier to produce with soft crayons than with hard ones, while the hard ones are best for fine shading and outlines.
The lampblack used for crayons must be burned out first, else it will develop blisters, which is the case also if the composition is poured on the plates too hot.
Crayon that contains much shellac is likely to soften in damp air; therefore it should be kept in tightly closed vessels.
IX
CONCERNING COLOR FOR PRINTING
The manufacture of printing-ink or color is very difficult and dangerous on a large scale. I counsel all to take lessons from a book printer when he makes it.
The varnish must be prepared in the open, far from buildings, because of its combustibility. The best utensils and skilled workmen are required, because otherwise terrible accidents may occur, and even life be lost through explosion of the copper receptacle. Whoever does not require as much as one or more hundredweight of varnish in a year, would better buy it from printers or make only a small quantity, one or two pounds, and in an open vessel. For this purpose I will describe the process.
One, or at most two pounds of good old but not rancid linseed oil are poured into a clean iron pan which has a long, strong handle and is so large that the oil takes up only one half or, better, one third of the space. This is heated over a good fire till it burns, which is facilitated by applying flame to it. Oil that is too new has much water and other impurities that make it froth and run over. In that case the oil must be poured into the pan only in small quantities, when one must take great care to avoid spattering. As soon as the oil burns, the pan is removed from the fire and placed in a safe spot. If it is hot enough, it will continue to burn. It must now be stirred from time to time with an iron rod. Usually the flame increases under this stirring, but sinks again immediately at its cessation. So long as it does this, there is no danger that the flame cannot be easily extinguished if need be. But when it begins to continue burning with a great flame after the stirring stops, and at the same time to bubble and froth, it is high time to cover the pan with a close lid and leave it covered till the oil no longer takes fire when exposed again to the air. Then a dry knife is introduced and as much oil removed as will adhere to its point. If it does not permit itself to be pulled into long threads when cool, but is too thin, it must be heated again until it gets the required consistency.
A good varnish dries very readily of itself, and it is not only unnecessary but inadvisable to mix a drier with it, as varnish so treated is too likely to off-set on the stone.
Several strengths of printing-varnish are needed for the various methods of lithography. Therefore a stock of thin, medium, and thick varnish is needed.
In making the thin, the oil has been reduced to about two thirds through combustion. It is somewhat like fluid honey and does not pull into threads.
Only a little more than half the oil is left in the case of medium varnish. It is thick as old honey and can be pulled into threads a foot long.
In the thick varnish the mass is not much less, but it can be pulled into threads of a yard in length; and further boiling makes it thick and tough like gum elastic. In the latter case it can be used with advantage when rubbed down with oil and properly thinned. But as soon as it has obtained the last-mentioned degree of thickness and toughness, it must be cooled quickly, for then it is not far from hardening completely and becoming worthless. In the beginning it requires a long while for the oil to reach the first degree of thickness, an hour or more for a pound. But after that period the thickening progresses rapidly, so that a quarter of the time will bring it to the point of total toughness.
To make printing color of the varnish, the proper amount of lampblack must be mixed in. The roasted or burned-out is best in this also, because the ordinary lampblack delays the drying and turns yellow with time.
The more lampblack is mixed in, and the more thoroughly they are combined by rubbing down, the better will be the color. But lampblack must not be added in such quantities that the color becomes dough-like.
In describing the various styles of printing I will describe the best printing-inks also. I will merely make the general note here that designs on stone take the ink best when it is thin and fluid, but that there is less danger of off-set on the parts of the stone that are to remain white, if the ink is tougher or contains more lampblack.
Too much lampblack and too tough a varnish endanger the finer strokes and dots, however, so that they will not take ink, being, as lithographers say, rubbed out. The rubbing or grinding effect of too tough an ink is like that of pumice or other grinding material. With tougher varnish, clearer imprints can be made and they do not become yellow easily. But the inking is more difficult and demands greater skill, as well as heavier pressure in the press.
The varnish can be mixed not only with lampblack but with many other colors, which will be described when I reach color printing in this essay. Sometimes black lacquer is used with advantage instead of lampblack; and Frankfurter black is successful in the intaglio and aquatint methods.
X
RUBBING-UP INK
It happens often that weak parts of a design cannot withstand the etching fluid and are cut away; also, that fine lines are rubbed away through unskilled treatment during printing. Then frequently a very simple remedy is to ink the plate with the so-called rubbing-up ink.
This color consists of a thin varnish in which a portion of litharge of silver or mennig or white lead has been dissolved thoroughly over the fire, and a proper amount of lampblack added. Often it is good to add some finely powdered sand or powdered pumice stone.
To prepare this, a portion of the thinnest varnish is heated in a pan till it burns. Then about an ounce of finely powdered mennig (or another lead oxide) is stirred in to each sixteen ounces of varnish till all is thoroughly mixed.
A rubbing-up ink can be made also by mixing common printer's ink with vegetable oil, tallow, and a very little soap.
Each of these colors adheres to all those places that have a trace of fat and thus gradually makes faint places in a design receptive again.
Later I will describe how to use care in applying this color, so that the entire stone shall not be smutted and spoiled.
[CHAPTER III]
CONCERNING ACIDS AND OTHER MATERIALS
I
GENERAL PROPERTIES OF ACIDS
Probably most lithographers still believe, as I did once, that the etching with acids prepares the stone, and that the succeeding application of gum merely increases this preparation. Countless experiments have taught me that the exact reverse is true. Gum arabic and a few other similar bodies are the true factors in preparation, and the acids simply make the stone more receptive for them. Only sulphuric acid, which changes the surface of the stone into gypsum, prepares it without gum; but this is available only for a few intaglio methods.
The stone used for lithography consists mostly of limestone sated with carbonic acid. Most acids, and even the salts, possess more affinity for limestone than the carbonic acid, which latter is freed and escapes in gaseous form as soon as another acid touches the stone. If aquafortis, muriatic acid, vinegar, etc., is poured on the stone, there rise a number of air blisters, which are nothing except the escaping carbonic acid, and the applied fluid seems to boil, in degree according to its strength. The boiling and bubbling last till the fluid has sated itself with lime, after which it becomes still, and is impotent for further etching.
The direct effect is the solution and destruction of parts of the surface of the stone. If it has been coated in parts with a fatty substance that resists the etching fluid, the places so coated are left untouched, so that, when the stone is cleaned, all the fat-coated lines and dots are in relief.
If the stone is coated with fatty matter, but not so thickly that the acid is entirely resisted, it will pierce the covering and eat away more or less of the stone. If the etching is continued or if the acid is strong, the fatty coat will be destroyed entirely, the surface of the stone will be clean, and ready for the ensuing preparation. The preparation of the stone for pen drawings with oil or soap-water and several aquatint methods, is based on this principle, that a very thin coating of grease can be etched away partly or wholly, at will.
After eating away the surface of the stone the acids have the property of giving it a fine polish.
Therefore if the stone has been covered with a design, and then etched with an acid, it could be inked and printed many times, as long as it is kept properly dampened and not too much pressure is used in applying the ink. However, this could be done also with a thoroughly clean stone, using only water, though the polish obtained from etching makes it much easier. But this apparent preparation is not by any means sufficient to print with certainty; and it becomes perfect only if the stone is coated with a solution of gum arabic in water after being etched. If a plate that has been merely etched and not treated with gum becomes dry during printing, or even if too much pressure be used in applying ink or in cleaning with the more or less smutty cleaning rags, it generally takes color and smut which are extremely hard to remove.
We may assume, therefore, that the acids have the following effects on the stone:—
(1) They will not attack the parts coated with grease.
(2) They will penetrate more or less if the fatty coating is only thin.
(3) Where they touch the stone they dissolve it and eat it away.
(4) They give it a polish that facilitates printing. This polish disappears after a time on account of the cleaning with sponge or rag, but is replaced by a new polish produced by this very means.
(5) They do not prevent the adherence of fatty material later, as soon as the stone is dry, for which reason the parts prepared in the beginning with acid and gum arabic must be prepared again by renewed etching, to take the ink.
(6) Finally the acids have the property of giving to prepared stones that have been used for impressions, a rough surface instead of a polish when they are applied again, because they attack some parts more than others, producing little pores with sharp edges which catch the ink. This fact, as I will show more clearly later, makes necessary extraordinary care if one wishes to clean prepared plates or correct defects with new etching, because unskilled handling will often make them worse.
II
THE ACIDS SPECIFICALLY
Nitric acid or aquafortis, muriatic acid, vinegar, tartaric acid, and acid of wood sorrel, all have nearly similar effects, but aquafortis and muriatic acid are used because of their greater cheapness.
Oil of vitriol or sulphuric acid, very much diluted with water, is available for light but not for extensive etching, because it transforms the surface of the stone into gypsum and deposits it again, so that after that the acid cannot penetrate at all, or only partially. If a part of vitriol, say diluted with twelve parts of water, is poured on a cleanly ground stone, there ensues a violent action which, however, is only brief. It might be supposed that the acid is sated with lime when it ceases to act, but if it is moved to another part of the stone it etches anew.
If the acid is washed from the stone and a woolen rag be used to rub it after it is dry, it takes on a mirror-like polish. In this dry condition it can be cleansed of color as easily as a copper plate, and if a stone thus polished is engraved with a steel tool, it is possible to make several impressions from it just as from copper. The polish is not lasting, however, because the skin of gypsum is very thin. But it is a useful method if it is desired to engrave the stone and ink it frequently to see the effect.
All the acids named have the property, previously mentioned, of etching the stone rough if it has been prepared before or used for impressions. It seems that the gum unites more strongly with some parts of the stone than with others, admitting the acid in these latter places. Possibly, also, the bubbles caused by etching may help to produce this roughness by hindering the uniform action of the acid. This seems to be confirmed by the fact that an etched stone, prepared with gum, does not get nearly so rough when etched again with very weak acid as it does when stronger fluid is used.
In still greater degree does this appear when using citric acid or a solution of alum in water. Take a finely ground stone, pour diluted aquafortis over it, prepare it with the gum solution, and then dry it thoroughly with a clean rag. Now pour a little citric acid or alum solution on parts of it and let it dry. Then paint the parts so treated with a fat or printing-ink. If the color is rubbed off with a wet rag, it will be seen that the stone has become white again in all places except those where the citric acid or alum are. Those parts will have taken the color exactly as if they had been painted with chemical ink. The same occurs when applying other acids, but in a lesser degree. This effect will be mentioned in future for many methods. Here I will remark only:—
It happens often that the stone takes color on places where it should remain clean. This is caused by clumsy handling, unclean rags, etc., and occurs particularly at the ends, because they dry first and are more exposed to careless manipulation. These smutted places usually can be cleansed with a clean woolen rag and gum solution or even with a wetted clean finger. But sometimes the defect will not yield so easily, especially if the printing-color is soft. Then the only remedy is to prepare the stone over again, and that is the time when one must have regard to the roughening that ensues, if the stone is not to be rendered worse instead of better.
Therefore it is best in such cases to polish the ends of the stone with pumice stone till all dirt is gone, and then to etch with diluted acid and prepare anew with gum arabic.
To be sure, it is possible to dip a clean woolen rag in strong, even pure acid, and thus etch dirt away from the ends; but great care is necessary that no drop may touch the design, as the ink that adheres to the latter is not strong enough to resist the acid. In thus cleansing the plate, the roughening is etched away by the violent action, and a new polish is obtained.
Still, in either method of cleaning dirty places, great care must be taken not to touch roughly, press, or rub with dirty fatty rags or with dirty, fatty fingers before the gum arabic is on it. The acid eats away all the previous material used in preparation, and leaves the plate practically in its clean, natural state. Consequently it will take on grease readily, and the application of gum is essential.
It is feasible to mix the gum directly with the acid solution, but this mixture must be made fresh again each day, as otherwise it loses much of its value.
The following points are important:—
First: If the grease remain long on a stone that, though prepared, has lost its coating of gum, it will penetrate the surface, and according to its amount and fluidity, will sink more or less into the stone, which will retain its polish on the surface but become more inclined to take dirt. It is better, therefore, to leave a small amount of gum coating on the stone in such cases.
Second: As only the extreme outer surface of the stone is prepared by the gum, and this is rubbed away gradually by wiping during the printing, so in the same proportion of wear and tear the original preparation would become lost, if it were not renewed from time to time, that is, if the stone were not again coated with gum. Twice a day, however, is enough.
Third: Because of this susceptibility of the surface to injury, a prepared stone must not be rubbed strongly with fatty material, because this damages the surface and the stone would readily soak up the fat.
Fourth: If a prepared plate is totally denuded of gum, and has been dry for a time, especially if it has already lost a part of the preparation through printing, it will incline very much to take color and smut. Therefore, when it is necessary to stop printing, it is well to coat the plate at once with gum, but only with a very thin coat. If this has not been done, and it is desired to use the plate again, great care must be taken to wet it with the very purest water, or, better still, with diluted etching fluid, for instance one part aquafortis to five hundred parts of water; and then to coat it with gum. To neglect this precaution may cause the total ruin of the plate. For safe-keeping of the plates, if they are to be used again for printing, the coating with gum is, therefore, absolutely necessary.
Fifth: Gum can prepare only a thoroughly clean stone or one properly etched. Therefore, if the surface of the stone has even the least trace of grease, it will take color, no matter how thickly it may be coated with gum. On this fact is based the method of transferring copper-plate impressions and other printed subjects, as will be described later.
Sixth: If the stone has had fat on its surface, and this fat has been etched away again, the power of the gum asserts itself, and the stone will be thoroughly prepared even if the fat has soaked considerably into the body of the stone.
Seventh: Mere grinding of the stone is not sufficient to attain a complete preparation through gum alone. Therefore, if an otherwise clean stone has some places after grinding where the fat has soaked in deeply, and one coats it with gum, the stone will take color after a time on these fatty places, as soon as the inked rag has been rubbed over the stone many times. However, this taking-on of color is only slight if the gum solution is thick, and long-continued cleaning will transform it into complete preparation.
Eighth: From both preceding observations we learn:—
Printing forces the color to sink considerably into the stone. If such a stone is required for new designs, it is not practicable to grind it so much that all the fatty places can be ground away. Therefore it is ground only till it is thoroughly even again. Then it must be well etched; otherwise it may happen that in printing the surface will rub away and the entire previous writing or design will appear again, a trouble hardly to be remedied.
If the stone is dirty in the middle, it can be cleaned in many cases by pouring on a few drops of oil of turpentine and the same quantity of gum solution, and rubbing it clean with a woolen rag. Then it must be washed with a wet sponge, after which it is inked. If it has not lost the smut, the only remedy is new preparation. As this must be done differently for each different lithographic style, it will be described in its place.
If fat has soaked well into the stone in places where it is not desired, it is always very difficult to remove it without injuring adjoining parts. Correction of crayon work, if it has been etched and used for printing, is especially difficult. It is true that the defective parts can be cut out easily with a sharp instrument, but then these places must be prepared again. If weak etching fluid is used, it will not suffice. If strong fluid is used, the fine parts are easily attacked, and at the same time the surface will become roughened so that the stone often blackens entirely in the corrected parts. To avoid this trouble, and to facilitate corrections, I made many experiments to discover an acid composition that should prepare a stone anew and perfectly and yet not roughen the surface. I found the best material in phosphoric acid, especially when mixed with finely crushed nutgall.
Water in which phosphorus has been kept a long time becomes acid and etches the stone. The acid can be obtained more quickly by burning the phosphorus and catching the smoke. This method is somewhat expensive, but one does not need much, as it is used only for correcting defects.
If a few drops of aquafortis or other acid are poured on a clean ground stone, it will be etched. Now wipe the etching fluid off clean and coat the plate with soap-water or chemical ink. As soon as it is dry, clean it of the fatty coating with a few drops of oil of turpentine. If it is dampened then with water and inked, it will take color everywhere, even at the etched places. If gum is mixed with the acid, the same result occurs, though the stone has been thoroughly prepared where this mixture touched it. From this it appears that soap-water (and the alkalis in general) can destroy the preparation given to the stone and make it receptive again to fats. It is different if phosphoric acid is used. This makes a preparation that can be destroyed only by very frequent coating of soapy water.
Still more durable and resistant to soap is the preparation if fine nutgall is mixed with the phosphoric acid and water solution. Nutgall gives even the other acids the property of resisting soap more than ordinarily. The study of this effect led me to invent the method of transforming a relief design into intaglio. Also, it is only by the use of phosphoric acid that one can do thoroughly that style of lithographic work which resembles the scraped style in copper, or the so-called black art.
III
GUM AS THE REAL PREPARATION
If a cleanly polished plate is sprinkled with a few drops of gum arabic dissolved in water, the sprinkled places will take no color so long as they are wet. When they dry, color will adhere, but can be washed away easily with a wet sponge. This shows that the gum alone will prepare the stone. The preparation will become more durable, however, if the stone is etched first.
In both cases, however, the preparation extends only over the outermost surface of the stone, penetrating only slightly, so that the least injury will make it take color as soon as it is dry. On this fact is founded the intaglio style of lithography. Therefore, if a clean ground stone is etched, then prepared with gum and dried clean, it can be coated with printing-ink or other fat substance (excepting soap and all alkaline compositions), and there will be no danger that it will lose its preparation. The thicker the gum coating, the less can the fat penetrate.
In printing, during which the stone must be kept wet, only the original coating of gum is necessary; but as the surface thus prepared soon diminishes under the frequent wiping, it is necessary in some forms of work to mix gum with the printing-color or with the water used to dampen the stone. More of this will be explained in the proper place.
Here I will add only that the domestic gum of cherry and plum trees is good for preparing stones some years and worthless in others, when it cannot be dissolved in water. In possessing the properties for preparing stone, the juice of many plants and fruits, sugar, and most mucous materials of the vegetable and animal kingdom, such as white of egg, approach gum arabic more or less. The latter, however, is to be preferred because of its reliability.
IV
CONCERNING PARTIAL PREPARATION
Here I impart my experiences in regard to an astonishing phenomenon that occurs often in lithography and gives much trouble, especially to beginners. It is the so-called imperfect or semi-preparation, wherein the stone betrays a strong inclination to take color, and still will not do it or will do it only partially.
(a) If a cleanly ground stone is marked with chemical ink, etched, and prepared, the marked places will take the printing-color and produce impressions. If, after the stone is inked, one rubs strongly with the wetted finger, the color can be wiped from the design, especially if it has not been on the stone long and has been standing in a damp place. A place whence the color thus has been removed does not take it readily when the inking-roller is applied again; and the reluctance is the greater in proportion to the length and violence of the rubbing and the toughness of the printing-color. The stone shows clearly the traces of the penetrating fat; indeed, if the stone is rubbed with a wet linen rag that is inky from previous use, the design will reappear in black. But as soon as the roller is used, instead of inking these places, it takes the color off; and whatever means may be tried to make the defective places receptive again to color, it remains difficult, often impossible.
What has happened is that the wet rubbing has cleansed the surface of the stone of all its fat and at the same time has polished it and made it slippery. It is a sort of preparation; and though the fat of the ink has penetrated into the interior of the stone, the accidental preparation still offers an obstacle which prevents the printing-ink from adhering to the fat in those places. As I will show, these places can be prepared again thoroughly.
(b) Another case is when the design is too weak, and has been attacked by the etching-fluid too powerfully, though without being destroyed. Here the printing-color usually is removed by the ink-roller, even though it adheres pretty well when being wiped.
(c) A third kind of imperfect preparation is when a stone inclines to take color or smut on prepared places. This happens sometimes in part, sometimes over the whole surface, which latter effect is described by saying that the stone has acquired a tone.
The cause of this phenomenon may be one of many. It is either due to the appearance of a fat that has been in the stone, or to the fact that unskilled manipulation has destroyed the preparation partially.
Thence follow several observations again:—
(1) Mere wiping with clean water will give the stone a sort of preparation if the material used for wiping is suitable. This preparation is incomplete, but can be transformed very easily into a complete one. This incomplete preparation is according to the strength with which the rubbing material affects the stone. Linen and cotton stuffs have the least effect. More potent are animal wools and hair, silk or wet leather. The printing-color itself has a preparing property if it is made of very tough varnish or contains much lampblack. This effect is increased if Frankfurter black or powdered charcoal is mixed with the color, and the stone is kept very wet.
(2) The partial preparation is produced more quickly and made more durable if the water contains gum or gummy stuffs.
(3) The operation is still quicker if a weak etching fluid is used. A stronger fluid would make the preparation a complete one, but would also injure the good spots. Then again one must remember that the second etching produces the roughness discussed already.
(4) Grinding with sand, pumice, and other grinding materials also produces partial preparation, which is transformed easily into complete preparation by applying gum. Here, however, the circumstance is noteworthy that a plate that has been blemished by rubbing can be made to do the reverse, namely, to take color, by means of light grinding with water. Assume, for instance, that a plate designed and prepared in relief style has been spoiled by handling so that the design refuses to take color. It is necessary merely to rub it all over with water and fine sand or to clean it with oil of turpentine so that all printing-color is removed from the surface. Then place it in a receptacle containing a great deal of very clean water. If it is ground delicately then with a very clean pumice stone, without destroying the traces of the fatty material that has soaked in, it can be brought to take color again as well as ever. Take a little of the before-mentioned acid-proof ink, smear it on the color-stone, and apply a clean linen or cotton rag. Wipe the stone that is lying in the water very gently with this rag, and the color will fix itself bit by bit on all parts of the design, even if the entire relief produced by the etching should have been ground away. It is necessary only that the fat shall have soaked in sufficiently; and this usually is produced soon enough by the printing. After the plate has accepted color completely, it is to be completely prepared by light etching and with gum, and then it will take the color properly from the ink-roller.
If this experiment is to succeed, it is to be noted that in grinding there must be no trace of fat on the stone or the pumice, because the rubbing during grinding might transfer this greasiness to those parts of the stone that are to remain white. Care must be taken, also, not to press too hard in applying the etching color, because the places that have been cleansed of all gum by the water, and thus are inclined to accept color, will smut easily. Finally, the stone must not be permitted to dry before it is fully prepared again by etching and gum coating, for it might easily become entirely smutted and useless.
This experiment leads to the conclusion, which has been proved correct in many ways, that a soft rubbing in clean water with printing-color, especially if it contains tallow, is very well adapted for transforming the incomplete preparation into a condition of accepting fat perfectly, and of giving injured places new potency. Also, that the contrary effect can be produced by violent rubbing, especially with wool, leather, or tough colors, because this prepares the wet stone and makes it useless for accepting fat. The first method may be used with advantage, therefore, for reëstablishing a vanished design. The second method is good for getting rid of smut. If the smut has occurred in previously clean and thoroughly prepared places, it can be destroyed entirely. But if it is only that the deeper fat has lost its superficial polish, and has appeared again, the stone will be only partially prepared by this last method and must be newly prepared on the desired places with weak etching-fluid and gum, for durability's sake. It is easy to see how important this circumstance is. With the one and the same process in various degrees of manipulation, opposite results can be produced; and I may declare that only he is to be termed a perfect lithographer who has exact knowledge of this especial matter.
(5) It has been mentioned already that every sort of preparation can be destroyed by a renewed etching, and particularly with alum and citric acid. The same is caused by soap and alkaline compositions; therefore also by chemical ink if it contains a sufficient amount of alkali.
(6) Simply letting the stone plate rest produces important, often contradictory, phenomena. If smeared parts refuse color, clean water poured over these places runs from them as quickly as it does from the fatty parts. This is the surest sign that they still have fat, though it is not sufficient to attract the color. If such a stone is permitted to lie idle a few days, even if coated with gum, it will often take the color thereafter. On the contrary, if a stone plate has taken on color at the well-prepared places (usually readily removable by wiping with oil of turpentine and gum solution, but generally reappearing), it need merely be inked after such cleansing, coated with gum and left idle, and in a few days it loses the readiness to take dirt.
The cause of both phenomena is that in the first case the fats that lie deep gradually work upward into the partly prepared surface and practically reëstablish their interrupted communication with the printing-color. In the second case, the small quantity of fat that has adhered merely to the surface has penetrated into the stone, so that it loses its effectiveness. Added to this, in the latter case, is the fact that the linseed oil, and the varnish prepared from it, acquire the property of losing their fats when they are dried in the air, and thus will take color poorly or not at all. This observation led to the invention of an artificial stone or stone-paper.
(7) In contrast with preparation by wet wiping there is the wiping with dry and fatty bodies, which produces full acceptance of color on the partially prepared plate, while in the case of the fully prepared plate there occurs at least partial color acceptance or semi-preparation. As every property of the stone can be used for good impressions just as well as it serves in unskilled hands to ruin a design, so in this case; the lost parts can be restored through proper use of rubbing with a dry, fatty substance, and the clean, prepared portions of the plate can be smutted. There will be more about this.
V
SHORT REVIEW OF THE PRECEDING
As the entire art of stone-printing depends on proper preparation, it will not be out of place to express my views as to the nature of the process. This will serve also as recapitulation.
(1) Limestone has countless little pores. These can soak up fatty as well as watery substances.
(2) These can adhere easily to the limestone particles, but are easily separated again, as long as the nature of the stone is not altered. This alteration is produced most readily by sulphuric acid, tartaric acid and phosphoric acid.
(3) Water evaporates from the pores as the stone dries. Gum and other slimy substances do not.
(4) Fats soak into the stone more and more. There is no means of destroying them except to remove the limestone itself by grinding or etching.
(5) Printing-color cannot adhere to the stone so long as a proper amount of moisture forms a wall between it and the stone. Under any circumstances it adheres only poorly to the lime particles, and assumes great power of adherence only when the pores of the stone are filled with fat, which are pinched in them, so to speak, and with which the printing-color strives to unite because of mutual affinity.
(6) This stronger adherence (or complete color reception) thus happens only when the outer color can reach and touch the inner fat. If the latter is deep in the stone, so that the communication is broken, it becomes difficult and the communication must be restored.
(7) This interruption occurs either if the color is rubbed away by force and with help of moisture, or if a substance that closes the pores unites with the stone.
(8) The rougher, sharper, and more angular the pores are, the more readily does the color find adhering points. It adheres at first to the surface by virtue of merely mechanical conditions. But when the moisture which hinders a complete union and greater penetration has dried, the color begins to penetrate deeper into the stone and to fill its pores. The most color will always adhere to rough spots. Therefore, it happens often, in some styles of work, that a stone too highly polished will seem perfectly black when inked, and still fail to yield a strong impression. For the same reason the impressions from soft stones usually are the stronger, especially if the mode of printing demands the use of thin printing-color.
(9) The effect of the etching fluid is in part a greater polishing of the surface, in part a filling of pores. Both make the stone reluctant to take color.
(10) If the stone has been prepared and polished already, it can be made rough again and receptive to color by being reëtched. At the same time the prepared surface can be destroyed by etching, and a communication established with the fat lying in the interior. The result is according to the manipulation.
So much in general. In describing the various styles I will make everything clearer.
[CHAPTER IV]
THE NECESSARY TOOLS AND APPLIANCES
In lithography there is use for many various tools and utensils. I will mention here merely those that are made primarily and exclusively for the art.
I
CONCERNING STEEL PENS
One of the most necessary tools of lithography is the steel pen for writing and drawing on the stone. Simple as its manufacture is in principle, it demands much care and skill. The beauty of the work depends largely on a good and well-cut pen. The best artist, using the best chemical ink on a perfectly prepared plate, cannot do good work unless the pen is good and cut to suit his hand. Therefore it is necessary to learn how to make these pens, because, apart from their costliness, it is difficult to get a suitable one from a worker in steel. The ordinary steel pens that can be bought ready-made from stationers are fairly available for coarser writing and drawing; but for better work one must have much finer pens.
Following is the way to make them:—
Take the spring of a pocket watch, not too small nor too broad; one and a half to two lines in breadth is best. Clean off all fat by polishing with sand or chalk. Lay it in a glass or porcelain vessel, and cover it with a solution of aquafortis and water in equal parts. Let the acid etch the steel till it has lost about three fourths of its thickness, and has become as pliable as a similar strip of letter-paper. From time to time the steel must be removed from the fluid and dried with tissue paper. This produces uniformity of etching. The steel rarely is quite uniform, and it has happened to me often that it is attacked unequally and that holes are eaten into it before it has been etched away sufficiently. That this, however, is due mainly to the quality of the acid, I learned because I found that the same steel would be attacked clean and uniformly as soon as I obtained aquafortis from some other source.
A pen is poorly etched if it has many elevated points or pits and holes. The former appears to result from insufficient cleansing, the latter is due to the quality of the acid.
Oil of vitriol diluted with water, or nitric acid can be used.
Those who have a very light touch may etch their pens to great thinness, and will be enabled to do very delicate work. For a heavy touch they must be firmer, otherwise fine strokes will look shaky.
When the steel is thin enough, it is removed and cleansed with fine sand that it may not become rusty in future. Then it is cut into pieces two inches long with good English shears. Now these must be shaped half-round. To do this, lay them on a flat stone and beat them lengthwise till they bend, using a small watchmaker's hammer, whose faces are pretty thin but well rounded. Two or three sheets of paper laid under the steel facilitate the work.
Another way to give it the half-round form is to file a groove into a stone, giving it the exact shape the pen is to have. Into this groove lay the piece of steel, put in a drop of vegetable oil, and polish with a steel instrument whose end resembles a broken but well-rounded nail. Use sufficient pressure, and the steel will gradually assume the desired shape.
Either of these methods may be used, according to preference. It is to be noted that the degree of roundness depends on the artist's need, one finding a well-rounded pen better, another preferring one not so well-rounded. The less the pen is rounded, the more it will resemble a brush when used, but the points will not spread so well without considerable pressure. The more they are hollowed, the stiffer are the pens and the more easily will the points spread when pressed.
After the pen is curved, it must be cut. With small, well-sharpened scissors cut a slit about one line in length into one end. Then cut away from the two sides as much as necessary till the point is sufficiently fine. Do not cut away too much at once, as the pen bends easily and then must be straightened out again, which demands especial skill. It is well to do the cutting from the point toward the sides.
A good pen must have both points very uniform, so that they touch perfectly and lie on the stone evenly in the position given them by the hand when working. The cutting alone will do this, but a small, very fine whetstone may be used to aid.
A newly cut pen is somewhat rough at times and cuts into the stone, thus gathering powder that hinders the work. This defect generally cures itself after a few strokes on the stone. Beginners generally spoil their pens by bending them every few moments. Then they must be straightened out, which demands practice and judgment. It cannot be described, because the bending may assume a thousand shapes. It may be mentioned, however, that the points must always touch, but must under no circumstances interfere, one being forced behind the other. It is good, sometimes, if one can see through the slit when looking backward from the point. Some even cut a tiny bit out of the middle for this purpose, but that demands great skill and extremely good scissors, as otherwise the opening will be too large, which will spoil the pen entirely.
The ordinary drawing-pens, which can be loosened or tightened with screws, can be used very readily for drawing lines, if their points are made from very good steel that can be ground very fine and thin. However, for much line-work, for instance the background of a picture which consists of lines hatched crosswise, it is better to use the other pens. The ordinary drawing-pens are too likely to catch a little dust or dirt between their points, and then will spoil the lines.
Of all work of the pen style in lithography, the most difficult is to draw very fine and even lines with a ruler. I have succeeded best by using a pen previously so cut or ground that both points touched in the position in which I was accustomed to hold the pen when guiding it with the ruler. It is evident that the pen must be held to the ruler on its side, so that the groove that contains the ink does not point in the direction of the ruler, but away from it. It is well if there is a tiny space in the slit, as it helps the free supply of ink.
II
CONCERNING BRUSHES
Brushes are used for various purposes, as to prepare the plates, cleanse, etch, etc. Here, however, we speak chiefly of the small brushes required for writing and designing. For this are used the very smallest and best miniature brushes, and they must be especially treated.
If it is desired that the brush make thicker strokes under pressure, the ordinary condition of it, in which all the bristles come to a point, is quite sufficient. But it is very difficult to lay on strokes of uniform thickness with them. Press the brush on the table, spread the bristles fanwise with a knife and cut away from each side about a half-line deep. Turn the pencil to the other side, stroke it again to spread it, and cut the same amount as before from each side. Continue this till there remain only ten or twelve bristles of the original length in the brush. Then cut these even at the ends. These should not be altogether the middle ones if the pencil is to be first-class. Neither should they be too far apart. They should hang together well when the brush is dipped into the ink, but not so closely that they will not let the ink pass well. With a brush successfully trimmed thus, the handsomest drawings, resembling copper plate, can be done with ease.
For coarser strokes, coarser brushes are needed. More bristles are permitted to remain in them.
III
CONCERNING ENGRAVING NEEDLES
These serve for the intaglio process, to draw into the stone, and must be of the best and hardest steel. In Munich there are also used the little five-angled watchmakers' borers, which are glued between two pieces of wood planed round in form of a pencil and so cut at the end that only a bit of the tool is visible. In using very thin needles one has the advantage that they are ground and sharpened easily.
For coarser strokes, coarser needles are needed. For fine strokes, especially if they are to go in all directions, the needles are best ground perfectly round.
IV
CONCERNING THE DRAWING-MACHINE
To transfer drawings very accurately and reversed on the stone, which is necessary especially in the case of charts and plans, a pantograph is used in Munich, which is so arranged that the stone is upside down and elevated. The inscribing-needle is just opposite the one that is managed by the hand, and when one follows the lines of the original exactly, there results a perfect but reversed copy on the stone. Such drawing-machines can be obtained from Herr Liebherr and Company in Munich. This skilled mechanician also makes a sort of pantograph of his own invention, with which drawings can be transferred to stone, reversed or otherwise, and in any desired proportion. Pictures of such machines may be obtained from him.
V
CONCERNING OTHER APPLIANCES
These are: a grinding-table, an etching-trough, some rulers, a writing-table, some music-writing pens and rastrums for those who wish to print music, small brush for spatter-work, a wiping-machine for the wiping method, several rollers and balls for inking, and some presses for wetting and pressing the paper.
Any firm table may be used for grinding, but it is better to have one made heavy enough to resist the strain of the powerful friction, and so made that the stones can be fastened on it readily. If this work is done in a room, it must have a depression in the middle and a hole, that the water may run off into a receptacle. Along the sides should be a low rim, that the sand and dust may not drip all over the floor.
The etching-trough is a square, well-pitched box whose bottom is depressed toward the middle, that the etching fluid may gather there and run through a hole into a receptacle, so that it can be poured over the stone again. The trough must be large enough to accommodate the stones easily. These must not, however, touch the bottom, but must rest on little pieces of wood or cross-pieces.
Besides the ordinary rulers, a large, broad one is required, about three to four feet long, five inches wide, and so shaped that on one side it is one-half inch thick, on the other only two lines thick. On this latter side a strip of pear wood must be glued and very truly planed off. Thus it can be used for drawing lines, although the real purpose of this ruler is only for supporting the hands when working on stone, that they may not touch the prepared surface.
If the work-table is made with high pieces at the ends so that the ruler can rest on them without touching the stone, no ruler supports are required. Otherwise one must have these two pieces, a little higher than the stone, so that the ruler may rest on them.
A specially made work-table has another advantage. In the middle there can be a turntable on which the stone rests, so that it can be moved easily into any position, something that is very difficult with large stones without this arrangement.
Music-writing pens are brass or silver tubes which have the shape of musical notes underneath, and which take up such a quantity of chemical ink that one can make about twenty notes without re-dipping. That they shall not take up too much ink, a fine wire is fastened in the centre. These instruments must be very exactly ground and their use demands some skill if the notes are to be uniform.
Instead of this instrument a piece of wood may be used, but this must be inked anew for each note. To avoid dipping too deep, it is best to spread some ink on a little stone and ink the instrument from this. It must be wetted in the beginning, that the ink may be sucked up about three lines high. After that the ink on the stone need merely be touched with it, and this makes the work very uniform. Beginners find this easy to use. But one works more swiftly with the other.
Of the rastrums, there is nothing to say except that they are of steel and very even at the ends so that they touch the stone in all places. They serve to draw the five lines for music. For making the broad strokes for notes, one can use coarse drawing-pens, or coarsely cut steel pens; but the best are those adjustable drawing-pens that are made from three blades.
The brush for spatter-work, the wiping-machine, and the dauber will be described in the description of the styles of work for which they are used.
Ink-rollers and balls are for laying on the printing-color. The latter are made from soft leather, stuffed with horsehair, like the ordinary book-printer's balls. The former are wooden cylinders with thin handles, of any requisite length and about four to five inches thick. They are wound with two or three thicknesses of woolen cloth and then covered very firmly and evenly with leather. Usually there is used sheep's leather from which the grease has not been entirely removed. Calfskin, worked white, is good and more durable. Dogskin is considered best. Some printers use soft red calfskin, turning the inner side out. The leather must not be stitched with linen but with silk thread, because linen does not take the ink as well as leather and silk do. The leather must be dampened when being drawn over the cylinder.
A fair stock of these rollers is required, because they are liable to become water-soaked during use, when they lose much elasticity and fail to give good service, so that dry ones must be on hand.
It is not well to have movable handles on the rollers, because then they are likely to roll over the stone too lightly and it is not within one's power to lay on the ink thoroughly. To prevent blistering the hands, thick leather covers may be used. Then it is possible to use any desired pressure.
Paper presses are needed both to obtain a uniform dampening of the paper as also to restore the proper flatness to the printed paper. Models are to be seen at the shops of all book-printers and binders.
[CHAPTER V]
CONCERNING PAPER
Three kinds of paper are used mainly in lithography. They are:—
(a) the transparent, oiled or varnished paper;
(b) underlay or waste paper; and
(c) the printing-paper.
I
TRANSPARENT PAPER, AND THE TRANSFER OF OUTLINES TO THE STONE
Oiled paper is used for tracing a drawing accurately and then transferring it to the stone either by transferring or by re-tracing it on the stone. It must have the following properties:—
(1) It must not smut the original drawing on which it is laid. Consequently it must be absolutely dry.
(2) It must be very transparent, like glass, so that the underlying drawing or painting can be seen perfectly.
(3) The ink or lead crayon used for copying must lie on it easily and plainly.
It is at its best if it is easy to work on it with a fine brush, using Chinese ink, or, (if the drawing is to be transferred directly to the stone), with the soft chemical ink described under the caption "[Transfer Ink]." Generally this can be done without further preparation in the case of most papers made transparent by oiling. Varnished paper, however, which is far more transparent, generally must be well washed with milk and dried again beforehand, that it may take the ink well and permit work with the finest strokes.
(4) Finally, a good tracing-paper must be very fine, pliable, tender and yet not in the least brittle. There is some very transparent varnished paper, but it breaks at the first attempt to bend it, so that it is hard to trace the drawing afterward on stone with the tracing-needle, because nearly every stroke tears the paper and the lines and outlines become coarse.
Very good transparent paper may be made as follows:—
Take the finest writing or vellum paper and soak it with nut or poppy oil, mixed with a little sugar of lead to make it dry more readily. When well soaked with oil, dry it a bit between waste paper and hang it up. Usually it is available in a few days. This paper is cheaper than the paper sold by stationers under the names of straw paper, etc., and about equally transparent. Still more transparent will it be if instead of the oil a varnish cooked from the oils is used. In this also the sugar of lead is an excellent drier. To make the varnish easier to manipulate and more readily penetrative for the paper, it may be thinned down with oil of turpentine. If it is desired to manufacture a greater quantity of this paper, one sheet is laid on another and painted with varnish. Then the whole mass is left for some time covered with a stone plate or a board, that the varnish may soak properly and evenly into all the sheets. Afterward the sheets are hung up singly to dry. The more varnish they have, the more transparent will they be; but too much is not good. Care must be taken that no drops of varnish adhere. It is best to brush the varnish evenly over each sheet before hanging it up.
Silk paper, such as is used in copper-printing to lay between impressions to prevent off-set, is still better for varnishing because it is finer. Only it must be very even and have no holes. The very greatest fineness of paper is desirable, for the reason that then the strokes made by the needle on the stone are fine and not coarse.
Instead of varnish made by boiling down nut or poppy oil, one can use Venetian turpentine, which merely has been thinned down with one half as much oil of turpentine. Such paper generally is dry enough after twenty-four hours. Too large a quantity must not be made at one time, because it becomes tough and brittle after a while.
Even with the most transparent paper it occurs that certain delicate drawings, and especially color pictures, will not show through sufficiently. Then the drawing must be fastened to a window pane to obtain added illumination. This manner of work is very uncomfortable, however, and the arms hurt one soon, so that it is necessary to stop. It is better to have a tracing-board made with a strong, clear pane of glass in the centre. Under it is a mirror so adjusted that it reflects light upward through the drawing.
It is understood, of course, that in tracing only the outlines are copied and not every stroke of shading, etc. Although the final work is greatly facilitated by the observation of the utmost care in tracing, the tracing of every little detail will merely make the work involved and perplexing. Practice must show the proper degree of exactness. A very good and skillful artist often needs only a few main outlines, to reproduce the original picture with the greatest accuracy.
Once the drawing has been traced sufficiently, the transfer paper must be coated very lightly and evenly with red chalk. Then it is fastened to the stone with wax and all the lines are traced under moderate pressure with a well-polished needle whose point is not sharp but rounded. Where the needle presses the tracing-paper, the color that is on the other side will take hold of the stone and thus transfer the drawing to it. If the needle is too sharp, it will injure the paper, and often the stone and the etching surface. The color on the paper must be rubbed off very carefully with a soft rag. If it is too thick, it will transfer itself coarsely to the stone. The red chalk may be put on the side of the paper that has the drawing on it, or on the reverse. This is decided according as the picture is to be on the stone in the same position as the original or reversed. If the impression is to be like the original, the drawing on the stone must be reversed; therefore in that case the tracing-paper is coated on the same side as the drawing. This side is laid on the stone, and the picture, which shows through, is traced.
In some cases it is good to transfer the drawing from the tracing immediately to the stone without tracing it with the needle. In this case, the paper is not coated with red chalk. The paper is merely laid on the prepared stone, drawing face down, and put through the press. If the drawing has been made with the chemical transfer ink, blackened with lampblack or colored with vermilion according to need, it will transfer itself to the stone. This will occur also in the case of a clean stone prepared for pen drawing if the drawing is made with lead pencil or with red chalk, wet or dry. Even the ordinary ink made from nutgall and vitriol of iron will transfer if it contains a little sugar or gum, but the paper must be well dampened and good pressure must be applied to the press.
In the pen-drawing process, the stone must be cleansed of possible surplus of color after the transfer. This is done by light rubbing with sand. It is not necessary in other processes. Any surplus of color that may have fixed itself to the stone is removed by gentle dusting with a soft brush.
II
WASTE PAPER
This is used partly for cleansing plates, partly and chiefly as underlay in printing.
If sheets are to be printed on both sides, usually a little of the first impression off-sets on the underlay paper, and if it were used again at once, it would off-set on the next impression. Therefore a fresh underlay paper must be used for each impression of the second side.
This must not be coarse, for fear of causing unevenness or holes in the leather in the printing-frame or in the so-called scraper-wood that makes the impression. A good quantity of this must be on hand, that fresh paper may always be available while the used paper is drying again. Each sheet that has been used should be hung up at once, and not more than three or four sheets should be hung over each other, to facilitate the drying. A special appliance is needed for this as well as for drying the impressions. A number of slats are fastened to the ceiling, leaving a space under it of about two feet, and about one foot distant from each other; and the sheets are hung on these with a pole made for the purpose, such as may be seen in any printery.
III
PRINTING-PAPER
Not all kinds of paper are equally good for lithography. On the whole, however, it may be assumed that this form of printing is very similar to copper-printing and book-printing, and that the paper that is good for these branches is suitable also for the stone, if only it does not contain too many impurities, grains of sand and other substances that make any considerable roughnesses. Such roughnesses, if considerable, have an ill effect not only on the impression, but chiefly on the leather in the printing frame. If the scraper is of wood, the leather will suffer less, but there will be caused grooves in the scraper that must be planed out again, because otherwise each following impression will show a more or less plain streak. If the scraper is of metal, the leather may tear or the stone itself may be injured if the foreign substance in the paper is very hard. Therefore it is well to hold the paper to the light before dampening or printing and to remove any apparent defect of magnitude with a little knife.
Usually the paper considered most excellent for copper-plate work is thick, tender, uniform paper, half-sized or not sized at all. It may be the same for lithography. However, it must not be supposed that good impressions cannot be obtained with sized paper. I have seen some that were as good as, and even better than, impressions made at the same time on unsized paper. Much depends on the dampening of the paper, on its make, and chiefly on the manner of sizing it. On the best sized English vellum paper, I have made blacker impressions than I could make on the best Swiss copper-plate printing-paper, so that I had to use fifty per cent less printing-color. On the contrary, in using an indubitably genuine English vellum paper with a bluish tinge, which had been sized only too well, I could not get good impressions despite all efforts. It was very hard to dampen also. Every sheet must be dampened singly, turned frequently and manipulated to smooth out the thousand irregularities that are caused by the moisture. Equally difficult to use were some sorts of genuine Holland paper, because they took color reluctantly. If, however, the correct degree of moisture is attained, if the paper takes it well, and, finally, if the color is right for it, it can be used with thorough success.
I must mention a circumstance that may defeat all efforts of a beginner should he try to use a certain kind of paper which is very handsome, durable, very white, well sized, but a little rough and possessing an odor somewhat resembling honey as well as urine. Sometimes it is called Kühnel, and comes from a French factory. This paper has the property of depriving the stone of its preparation, and consequently to smut it. This paper can be used only for dry printing, where it does not require any dampening at all.
It is said that this property of smutting the stone is due to the chemical bleaching. Others ascribe it to a peculiar kind of size. Perhaps it is both. The same defect is found in many sorts of colored papers if there is much alum in the coloring-matter, or if the tints are made from alkaline colors or those that contain soapy matter, or if it has been smoothed with soap. This, however, is readily understood after my explanation of the chemistry of the stone.
IV
DAMPENING THE PAPER
Dry paper may be used for printing. In certain work it is necessary, in order not to spoil the paper. As a rule, however, paper is moistened in lithography as well as in other forms of printing, to make it softer and more receptive to the printing-color.
After what I have said of chemical printing, it would seem that, as dampness is antagonistic to the reception of color, the moisture of the paper would hinder, rather than aid, printing. But experience proves the opposite. A damp paper takes color better than a dry one.
But this is not because damp paper is an exception to the rule. On close study, we see that here, too, it only proves all that I said about the stone.
Perfectly clean, and especially unsized paper, refuses color like the prepared stone, when it has been wetted thoroughly so that it is saturated. But here, too, mere water is not a complete preparation. Under strong pressure it is forced away readily from the paper, the printed places are dried and the color adheres. If the pressure is not sufficient to force all the water away, the impression will be imperfect. The tougher the printing-color is, the more will it resist the dampness and the greater must be the pressure.
Experience has taught me the following:—
(1) Every paper not spoiled with fat will permit itself to be prepared, like the stone, with water so that it will take no color. In the case of entirely clean, unsized paper, water alone is sufficient. Mucous, gummy, and acid substances increase its power. Unsized printed paper need merely be dipped in water, laid on a stone, and coated with oily color, and the printed parts will all take the color while the rest of the paper remains white.
(2) Any great pressure will remove this preparation and the whole paper will take color.
(3) The oil color must be very thin and fluid, because a tougher one will take hold of the fibres of the paper and tear them off.
The foregoing experiences applied to the theory of the print itself lead to the following conclusions:—
(a) The paper to be used for printing must never be too wet, because the most powerful pressure could not remove the water sufficiently.
(b) Paper that is too wet is prone to adhere to the stone with its printed parts, which are likely then to tear away easily, thus damaging or ruining the work. This happens the more readily if the pressure be not sufficient. If the scraper or the stone is not uniform and even, it is very prone indeed to tear at the places subjected to the least pressure, because there, where the water has not been sufficiently squeezed away, the paper remains soft and fragile, while the pressure still is great enough to grip the fibres of the paper.
(c) Therefore the paper must be only slightly dampened if the color is very tough, partly to prevent tearing, partly to oppose no undue obstacle to the reception of the color.
(d) Paper dampened too much stretches in printing and produces uneven and dirty impressions.
(e) The quality of the water is not important so long as it is not dirty or putrid, in which latter case it may infect the paper and rot it.
(f) Just how much the paper must be dampened can be learned only from experience, because papers vary very much and in the case of sized papers it depends chiefly on the kind of sizing. On the average, we may calculate one wet sheet to eight dry ones in sized papers and one wet one to ten or twelve dry ones in unsized papers.
The following is the best way to dampen paper: Lay two or three dry sheets on a straight board. Then dip a sheet into water. Let the water drip off a little and lay the damp sheet carefully on the others. Now lay eight or ten dry sheets on top of this. Then put on another wet one and then eight or ten dry ones and so on till all the sheets destined for printing have been so piled up. Put over all a board weighted with a medium heavy stone plate. After half an hour increase the weight to several hundredweight or squeeze the paper in a press. Leave it thus at least twelve hours. Then it is generally ready for print. In aquatint it must be dampened more, about six dry sheets coming to one wet one.
Very thoroughly sized paper is easier to moisten if each sheet, or at least each second one, is wetted with a sponge.
Sometimes it is necessary to turn the dampened paper in order to remove the creases. Separate the sheets into two piles and lay a few sheets from one to the other so that the altered positions will press the sheets flat again.
With many papers, especially the unsized, it is possible to use the method of book-printers, who immerse a whole book in water and then lay the sheets in two equal parts. This would be best studied at a printer's. It requires much practice.
If dampened paper is permitted to lie some hours without being weighted down, the margins will become too dry, and then there will be creases during printing, which can be remedied only by a second dampening. The reason is that dry paper is not so large as wet paper, so that the dry margins form a kind of frame which is too small for the inner wet portion.
In printing-processes that require many plates, and especially if the sheets are large, only dry paper can be used, as otherwise the register will be imperfect. To be sure, it can be done by using great care, but too much practice and attentiveness is needed.
With the exception of the aquatint processes, good printing can be done with dry but unsized paper. But the press must have twice or thrice the pressure. This makes the printing more difficult and endangers the stone if it is not thick.
[CHAPTER VI]
PRESSES
An exact description of all presses used hitherto for lithography would demand a book that would nearly equal the present one in magnitude. Many drawings would be necessary, which would increase the cost of this text-book without adequate benefit, as I have learned that one rarely can find a mechanician skillful enough to make a machine even when he has the very best description and a perfect illustration before him. I advise all who intend to enter lithography to send for a model to Munich or some other place where the art is being practiced with success. I myself am willing to furnish exact models for the price of one louis d'or, which must be remitted with the order.
There is no press as yet that is so perfect for lithography that it leaves nothing to be desired. The press whose plan I laid before the Royal Academy of Sciences in Bavaria, which does its own inking-in and which can be worked by water-power, has not yet been built on a large scale, so that its value cannot be stated exactly.
I am only too well aware, however, of a grave defect in lithography, which is that the beauty and even the number of impressions depend mainly on the skill and the industry of the printers. A good press is necessary, to be sure; but even with the best a poor workman will produce nothing but trash, because in this respect lithography is far more difficult than any other printing-process. I shall not admit that lithography has made a great step toward the utmost perfection until the erring work of the human hand has been dispensed with as much as possible and the printing is done almost entirely by machinery. Therefore I am determined to realize the ideas I have in this direction and I shall inform the friends of the art of my success at once.
I
PROPERTIES OF A GOOD PRESS
It has been observed that inscriptions, and particularly drawings, look better on the stone than on the impression afterward made from the stone. Partly this may be due to the color of the stone which softens the picture, because an impression made on yellow paper resembling the stone color looks very much like the drawing on the stone. But the great cause of the difference is that the color does not transfer itself to the paper with the degree of strength and clearness that it possesses on the stone. That this perfect degree can be attained, none the less, there are many successful impressions to prove.
If the plate is well designed and well prepared, it will take the color well and clearly, but the printer may apply too much or too little, the color may be too hard or too soft, or, even if the stone is properly inked, the paper may accept color poorly or be too damp or dry. Chiefly, however, it is the press, according to my experience, that most affects the quality of an impression.
In most lithographic presses the printing is done by the so-called scraper. This is a thin slat of hard wood, mostly maple, pear, or boxwood. It is one line thick on the side intended to do the printing, and the mechanism of the press forces it on the paper, which is on the stone and covered with an overlay of waste paper and tensely stretched leather. This pressure forces the color against the paper along the whole length of the slat, and only one line broad. The scraper is forced bit by bit over the entire plate, or it remains motionless and the plate is drawn underneath it.
It will be observed that this kind of press does not produce the entire impression vertically and at once as in book-printing, but that it is successive, as in copper-plate printing, with the difference that the copper-plate press uses a roller instead of a scraper.
As the scraper must be pressed down with great force (often as much as sixty and more hundredweight) and must pass over the leather with this immense pressure, there is a tremendous friction, and despite the fact that the leather is tensely stretched and lubricated with fat, it is considerably pulled and strained by the scraper. This pulling and straining communicates itself to the paper under the leather. Thus all the lines of the design become a little bit squashed in the direction described by the scraper. If, however, the leather is very good and very tensely stretched in the frame, if it is well lubricated, and if the printing-paper with its underlay is not too wet, the pulling is inconsiderable so that scripts and drawings in broad effects are not affected noticeably. Drawings in detail, however, and crayon work wherein there is hardly a perceptible space between the dots, are so affected by the slightest displacement that they produce a smeared, sooty impression.
The scraper has a second fault. If the paper has impurities, it injures the scraper readily. A groove scratched into the scraper will prevent any further good impression if the injury is considerable, because it will leave a streak. The only remedy is to take the scraper off and plane it, fashioning it accurately to the surface of the stone. I have tried to remedy this by making a scraper of metal. As this causes even more friction than wood, I laid a strip of strong paper over the scraper, which generally was good for three hundred impressions before it was worn out. Then I merely needed to move it forward a bit; so that a strip of paper as long as the scraper and six inches wide was available for some thousands of impressions. The pressure attained with a metal scraper is greater than with wood; but it has the disadvantage that it is hard to print a stone whose surface is not absolutely level, whereas a wooden scraper can be planed to suit any irregularity in the stone.
The foregoing shows that a good lithographic press must have these two properties:—
(1) It must not pull or shift the paper in the least.
(2) It must produce a uniform impression without weak spots or streaks.
The other properties it needs in common with other presses, such as:—
(3) It must be powerful enough to produce the necessary pressure.
(4) It must combine the greatest possible speed with this power.
(5) It must be easily operated, to save the workman.
All these qualities combined are not to be found in any press hitherto applied to lithography.
II
APPLICATION OF BOOK- AND COPPER-PLATE PRESSES TO LITHOGRAPHY
If we consider the peculiarities of book and copper print, we find a decided difference between them that affects printing importantly.
The letters of book-type are raised, the engraving in copper is depressed. It is evident that the former requires no such power for making impressions as the latter. Therefore the presses are so different that copper plates cannot be printed on a book-press and vice versa. Now, as the stone combines both the elevated and the depressed principles, the natural idea would be to combine the fundamental principles of both presses as nearly as possible for stone-printing. In book-print, only the types are exposed to the pressure, and in the average printed sheet these are only one fourth part of the entire surface. The remaining white space is not affected at all by the press. In the stone, however, the elevation of any part of a design is so slight that the entire surface is affected, and consequently a stone plate offers four times as much resistance. A book-press therefore would print a stone only if it were arranged for a pressure four times greater. Now, for a stone of the size of a letter-sheet the power required to print with one vertical pressure would be five or six hundred hundredweight, a pressure that could be supported only by a thick stone laid very exactly on a perfect foundation.
An ordinary copper-plate press increases the pulling of the paper so much in the case of a stone plate that the impression would be worthless. This pulling is not caused, as in the case of the scraper, during the impression itself, as already described, but it is caused before the impression through the endeavor of the cylinder to force the plate along under it. Once the stone is under the cylinder, the paper is not pulled noticeably, because the cylinder glides over the leather much more gently and with much less friction than the scraper.
This defect might be corrected:—
(a) By supporting the cylinder so that it would come down on the stone only at the point where the print is to begin. But as the stone must be drawn pretty well forward for convenience in inking, this would demand that the cylinder be revolved forward and backward again as far as is needed for the impression, which means a great demand on the strength of the printers, not to count the loss of time.
(b) A second way would be to plane off a piece two inches wide from the cylinder at the point where the impression is to begin. The stone could be forced under this space readily, and when the cylinder revolves, it presses forcibly at once without pulling the paper very much.
(c) The press might be fitted with iron wheels with cog teeth to engage similar cogs on the cylinder. This would prevent pulling, but the mechanical work would need to be very accurate.
(d) The best arrangement will be the following: Set the upper cylinder so high that the stone can be brought under it without touching. Then bring it down with a screw, or better still, with a lever that can be operated by the foot.
The first figure in the [plate] showing presses represents about how a copper-plate press is to be fitted for this work. On the whole, this is an ordinary copper-plate press, but the upper roller is set with its two axles or spindles in two iron levers, each of which is fastened to a piece of wood with iron screws one inch thick. Each of these pieces of wood is covered with strong sheet iron and can be adjusted higher or lower with two screws or with underlay of pasteboard. This is necessary that the press may be adjusted to varying pressures. The two other ends of the two levers, in which the cylinder sits, can be raised or lowered, so that the cylinder also can rise or sink. Now two springs or two weights are so adjusted that the cylinder with the levers always remains elevated. To force it down on the stone, an iron beam enters both sides of the press with two pegs so adjusted that when the beam is turned ninety degrees the levers are depressed at least two inches. As the cylinder is about in the middle of the two levers, it will thus be depressed one inch, which suffices to permit the stone to pass under it freely while it is elevated and gives the greatest pressure when it is depressed. However, the upper cylinder must not be one inch distant from the stone, but at the most only one fourth inch, for the remaining space of three fourths inch is required to provide margin for the elasticity of the various materials, and also to give margin for increased pressure whenever demanded.
On one end of the iron beam with the two pegs is an arm or lever which is joined to a thin stick with a treadle. This tread is so arranged that it remains elevated of itself. If the pressure is to reach sixty or more hundredweight, it must not be fastened directly to the treadle, but a second lever is required which is affixed to the side of the press.
Without going into tedious detail I cannot further describe this press. Mechanicians will understand me readily and perhaps be able to add many improvements. My belief is that a copper press so arranged would diminish all danger of squashing and pulling the impression, furnish powerful pressure, permit overlays of felt or fine cloth, and make possible considerable facility and celerity, which is a great advantage, because impressions always are better if too much time is not lost between inking and printing.
To safeguard the stone against cracking in such a press, the following points are to be noted:—
(1) The stone must be ground very true on the under side as well as the upper.
(2) Both cylinders must be perfectly true, and care is to be taken particularly that one cylinder is not thin toward the middle and the other thick, as this would easily crack the stone lengthwise.
The board on which the stone rests must be equally true and uniformly thick. At the same time it must be very thin, only one half inch thick at most. It will get very heavily squeezed during the printing, and the more the impression approaches the centre, the more concave will it become. The parts farthest from the point of pressure then resist unduly if the board is thick, and thus become the chief cause of cracking the stone. If the rollers are very true and the stone is very uniform, it is almost impossible to crack it if it is passed between the two rollers without a board underneath. If the board is thin, it is as if it were not there.
I believe that competent mechanicians can improve the present presses greatly.
III
LITHOGRAPHIC PRESSES USED HITHERTO
Most owners of lithographic printeries have tried their hands at inventing presses, but in the end it has always been something based on the scraper or the cylinder principle. I myself have made more than twenty designs. Some were very useful and had advantages either in power or convenience, but generally were handicapped by some defect, so that I cannot even say with certainty which was the best of them all. So much depends on the mechanic's execution of one's plans, and a perfect design can be so spoiled by a workman that it is worthless.
I will, however, recount the best that has been done so far for lithography.
In Munich two kinds of stone presses are mostly used. They are:—
(1) The lever press, or, as the workmen generally call it because of its form, the Gallows Press.
(2) The Cylinder or so-called Star Press, the latter term being used because a star-shaped lever is commonly used instead of a crank to turn the rollers.
I have tried and found good the following:—
(3) A press with double levers.
(4) A gyrating or sliding press.
(5) The roller press used by Herr Andre.
(6) And the press of Herr Steiner in Vienna.
Herr Müller in Karlsruhe and Herr Ackermann in London have a press with paper cylinders the construction of which is unknown to me.
IV
THE LEVER PRESS
This was the first press that I used with advantage, and it is used still in Munich in all important establishments for work that demands speed particularly. It would be an excellent printing-machine in all respects if it did not have the defect that its power cannot be increased much more than six hundredweight without forcing the workmen to undue exertions. Therefore it is no longer available for large plates or for works that require immense power. It is very good for pen designs not larger than a letter-sheet, and two workmen, one to ink-in and the other to print, can produce twelve hundred impressions in a day without hardship.
The pressure is produced by a lever six to twelve feet long, fastened to the scraper below and to a spring (an elastic board) above. It is connected with a tread, and when forced down, presses with the desired force on the scraper and so on the plate. The board holding the lever overhead must be partially movable like a spring because the lever describes a part of a circle on the plate below. Hence the pressure at the beginning and end of the impression is not so great as in the middle, and great care in choice of wood and manufacture is demanded to give the spring board the necessary elasticity and power combined. I have found a board of young dried pine the best, the dimensions being six feet long, eight inches wide, and two inches thick, provided that the fibres all ran lengthwise. It is not always possible to find a good board at once. Often I have found that the difference between two boards made a great difference in the effectiveness of two presses otherwise exactly the same.
The scraper arm consists of two parts, of which the shorter one, to which the scraper is fastened with a screw, is only one and one quarter feet long. The other part is as long as the height of the press permits. The higher a lever press is, the better is it, because then the circular motion described by the scraper wood approaches a straight line more and more, so that the press exercises a more uniform pressure during all stages of the impression and is easier to handle. The second illustration shows this kind of press in the moment when the impression has been finished, the printing-frame opened, and the scraper arm swung back again.
The printing-frame is much like a book-printing frame, and is furnished inside with a second small frame which holds the paper, being furnished with small springs or strings. When the frame has been turned over the stone, the paper must be at least half an inch from the stone to avoid smutting, which will occur if it touches. The paper must not touch the stone till pressure is applied, and then only on the spot pressed downward by the scraper.
As soon as both parts of the scraper arm are in a straight line, so that they form practically one piece, the scraper wood is pulled down and the printer draws it toward himself over the printing-frame and the stone plate. At this time the following is to be observed:—
(1) Both parts of the arm must be so fastened to each other that they may be bent like a knee, but once they are straight in line, they must stay in that position. It is well, therefore, so to adjust the parts that they will not be directly over each other, but rather exceed a straight line under pressure, and bend a little inward. The position of the scraper must be considered also. On the whole the following rule holds good: the point where both parts are united with a nail or a screw must not be in a perfectly straight line between the point where the scraper rests and the point where the arm is fastened above, but should be at least two and a half inches forward of that point. Otherwise the arm may spring outwards toward the workman and injure him severely. The third illustration shows the construction of the scraper arm and the scraper.
(2) The arm must be grasped as low as possible when being drawn toward one's self, in order to diminish the danger of springing outward.
(3) The workman must press his body tightly to the table of the press to get proper leverage. Standing free, a man of moderate strength could not move the scraper at all when the pressure is on, but a man standing in correct position can do it without difficulty.
(4) Under very heavy pressure the inker-in, who stands on the other side of the press, can help by pushing.
The scraper is a piece of pear wood as long as the size of the plate demands. Its height is about four inches, its thickness one inch. The end that rests on the leather is trimmed down so that it has a thickness of only one line. This end must be especially true and planed to fit the stone, also neatly rounded off. It should be so fastened to the arm that it may be adjusted to the position of the stone. The stone does not always lie truly horizontal in the press, sometimes because it is not uniformly thick, sometimes because the underlay is not quite even, and sometimes because the press itself has been a little strained. If the scraper has been made properly, it will adjust itself to the stone, even if the scraper arm is not quite plumb on the stone, a condition that often occurs with small work, such as titles and other things that are at the end of a stone.
(5) For every press a number of scrapers of different dimensions must be in stock. Generally a lever press is so made that the printing-frame can be raised or lowered according to the thickness of the stone. Then the scraper must be changed accordingly.
(6) The connection of the upper board with the tread is made by a thin stick that is fastened to a lever below, by means of a small iron piece which contains several holes that serve to adjust the height of the tread according to need.
(7) The leather in the printing-frame is strong calfskin. It must be stretched very evenly and tensely and must be smeared from time to time very thoroughly with tallow.
(8) On the outer side of the frame there are four wooden strips that can be adjusted as desired. One serves to show the point where the impression is to begin. Another shows where it is to end. Both must be so strong that they can resist the scraper. The other two are adjusted at the sides and guide the scraper.
V
THE CYLINDER PRESSES
When Herr Professor Mitterer installed a lithographic institution for the Feyertags-Schule, the lever press appeared to him to demand too much labor, especially when powerful pressures were desired. He invented the so-called Cylinder or Star Press, which has its place in most establishments, especially those in other countries. It has had minor changes made in it by many persons, but on the whole, nobody has succeeded in improving it notably, except for a considerable improvement made by Herr Mitterer himself. My description will include this improvement.
The cylinder press might almost be called a reversed lever press. Herr Mitterer borrowed from it the idea of effecting the impression with a scraper, but he did not let it move over the plate, as in the lever press. He gave the scraper a fixed, immovable position while the stone was drawn through underneath, thus making his press resemble a copper-plate printing-press somewhat.
Illustration number 4 shows this machine in the moment when the impression has been made. In the middle of the machine is a cylinder ten to twelve inches thick and as long as the breadth of the press. It has strong iron spindles that revolve in well-lubricated brass bearings. Above the cylinder is a board on which is fastened the stone with the printing-frame. The scraper is on a strong lever that is held up by a counterpoise. When everything is ready for printing, the scraper is forced down. By means of a strong iron hook it engages the treadle and thus can be pulled down with the utmost tension. Then the cylinder is turned by means of two levers affixed to the crank, and this draws the stone and printing-frame through under the scraper. One workman alone can do this under ordinary pressure, but an appliance at the other end of the press enables a second workman to help.
VI
GYRATING SCRAPER AND DOUBLE LEVER PRESSES
I have already mentioned the gyrating scraper press. I have improved it considerably. It has the form of the ordinary lever press, but all the parts can be much lighter. For instance, the lever is only one and a half inches thick. The spring (the elastic board) is very elastic and need exert a pressure of only one hundred pounds. The little scraper is only an inch long and presses on the plate with a force of fifty pounds. The press is useful for very thin stones that might crack under greater pressure. The pressure, nevertheless, is great, because it is all exerted on such a small area. The press has two defects. It is easy to miss many parts of the design with the small scraper, and the paper is likely to stick to the leather, producing poor register. I have obviated these faults with the following invention: A large scraper is fastened to the lever to press on the plate with a force of one hundred pounds. A small one is fastened to this in such a manner that it can be moved to and fro easily. While one workman rubs to and fro with the small scraper, another draws the entire stone and printing-frame slowly along under the large one. If good underlays are used in addition, this process will produce beautiful work that cannot be produced so well with any other machine. However, a large field is left in this form for improvement.
The fact that the concentric motion produced by a single lever can be transformed into an almost straight motion by use of a second lever, led me to design a double lever press, which has turned out very successful, giving great force with speed. As its description would demand much space, and since on the whole it ranks equally with the improved cylinder press, I offer to send models to those who desire to have everything useful for the art.
VII
THE OTHER STONE PRINTING-PRESSES
The cylinder press of the Chemical Printery in Vienna would, without question, be of excellent service for the art if it were more powerful. Its construction is as follows: The stone is fastened to a table with the printing-frame which has fine felt instead of leather. To make the impression a brass cylinder eight inches thick is rolled over it. As this cylinder would not produce enough pressure from itself, despite its massive make, two iron beams are fastened to the axles. They pass through the table and are fastened to a box that contains iron or leaden weights. Unfortunately the space prevents the use of more than five or six hundredweights, and this is too little for the large surface of the cylinder, thus forbidding any sharp, clear impressions.
This kind of press could be greatly improved if it were built higher to give more room below for weights, or the beams could be lengthened and passed through the floor into a lower room, thus giving space enough to add weights up to fifty and more hundredweight.
The press of Herr Andre is much like this, except that its cylinder is only three inches in diameter and that it is forced on the stone not with weights, but with a lower cylinder that presses upwards. It prints fast, like the other, but does not possess enough power.
In conclusion, I must remark that the concentration of ideas caused by writing this chapter has led me to begin experiments toward making a lithographic press which shall leave nothing to be desired. As soon as my affairs permit, I shall execute this on a large scale, and if the result fulfills my hopes, it will be a pleasure to describe it accurately to all friends of my art, or to furnish them models at cost.
[PART II]
CONCERNING THE VARIOUS METHODS
There are two principal methods of stone-printing, Relief and Intaglio.
In the former, the fatty parts of the stone are not attacked by the etching fluid, while the rest of the stone is dissolved more or less. Therefore the fatty places are left in relief.
In the second method, the design is either engraved into the stone with a sharp steel instrument or etched-in with acid.
The relief method has the advantage of greater speed and, generally, a greater number of impressions. It is easy for the artist to apply, especially in crayon work. The intaglio, however, makes possible finer and more powerful work, and again, in many cases, is the easier of the two for the artist. Therefore it is impossible to say in a general way which is the better. It depends on the work to be done.
[CHAPTER I]
RELIEF METHOD
To this method belong principally: (a) Brush and pen designs; (b) the crayon method; (c) the transfer method; (d) the wood-cut method; (e) a sort of scraped style; and (f) spatter-work.
I
BRUSH AND PEN WORK
This is one of the best in lithography, and perhaps the best, because it touches daily needs most directly. It can be used not only for all kinds of writings, but also for illustration that does not demand the supreme perfection of copper plate. The ease of manipulation, the speed and the almost countless number of impressions recommend it especially. It may even be prophesied that in future, when true artists have become better acquainted with it, it will be used for high forms of art.
Much as this method has to recommend it, it has been used mainly for script and music, and it is difficult to gain adherents and followers for it. The reason is an apparently trivial thing, but it has made most artists averse to it. Since stone-printing exists I have found only two persons who could do anything with the steel pen at the first attempt. These were my brother Klemens, and a Herr Porner, who works now in the establishment of Herr Müller in Karlsruhe. All others have had to struggle more or less with this slight trouble, and yet it does not demand more than a few days of patience and study.
For pen work one must not be too particular in selecting stones, as the less perfect ones are more available for this than for any other method. However, the general rule holds good here, too, that the purest and hardest stones are best.
If they have been used previously, so that the fatty inks have penetrated pretty well, they still need not be ground too deeply, but it will suffice to grind them merely till all depressions and elevations of the previous design have vanished. They may be ground with sand or pumice, so long as they are made smooth so that no roughness can be perceived. The smoother and finer the surface is, the easier will it be to work on it with the pen.
To design well on stone with chemical ink, the stone must be prepared after grinding so that the ink shall not flow and spread. Dissolve one part of tallow in three parts of oil of turpentine and coat the dry stone very quickly. With a clean rag or tissue paper wipe it at once so thoroughly that the coating vanishes again almost entirely, leaving only a thin film that can be easily devoured and removed when the etching fluid is applied later. It is well to do this some hours before beginning work on the stone, partly to give the turpentine odor time to evaporate and partly because it is easier to work after a little while than immediately after coating the stone. The stone can be prepared far in advance, even so long as some months before using. In that case it is necessary merely to clean the dust away with a cloth or fine brush. This should be done anyway at intervals during the work, or it will clog the pen.
I prefer another way of preparing the stone for designing, because it is one that insures the stone against containing any hidden preparation, which can easily occur in grinding owing to carelessness or uncleanliness on the part of the workman, especially if many old plates are being reground, when the gum which most of them contain from previous use will mix with water during grinding and thus form a partial preparation of the stone.
I coat the plate with strong soap-water containing many soapy particles, and dry it off as well as possible. Now, there will be too much alkali on the plate, which will not be good for fine work. I pour a few drops of clean water on the stone, make it quite wet with this and dry it again thoroughly. The fat of the soap will then have precipitated itself on the stone and at the same time has lost all alkali. The soap-water must not be too thin, as in that case it will precipitate too much fat on the plate at once and the etching fluid will not be able later to destroy it properly. This would mean the total destruction of the design. To make quite sure, I advise beginners, after applying soap-water and drying it, to coat the stone with the tallow and turpentine solution, clean it quickly, and thus be absolutely assured that the plate is thoroughly prepared for the design.
It must not be imagined that this preparation for work is not very important. I am convinced that less depends on the quality of the ink than on a surface freed from all acid and mucous substances and provided with a sufficient amount of fat.
On the stone thus prepared the rough design may be done with lead crayon or red chalk or by tracings or transfers. Any surplus of lead or red chalk would make trouble during the succeeding completion of the design with chemical ink, and must be removed carefully. If the design has been laid on by transfer, the resultant fattiness must be lightly rubbed away with a fine sand, but not so as to injure the design.
This method, of first drafting the design on paper with soft chemical transfer ink and then transferring to stone, offers such advantages that it pays to practice it. Care must be taken to remove all surplus of color, as otherwise all lines that should not appear will resist the etching fluid and gradually show again. Those who fear destruction of the design by the use of sand can effect the same purpose by printing off on clean waste paper a few times, or the design may be printed off on paper before being transferred, thus cleansing it of surplus fat.
When the design has been laid on the stone clean and strongly with chemical ink, the plate can be etched and prepared, but not till the whole design is perfectly dry, because otherwise it cannot resist the action of the fluid.
The parts finished first usually are dry long before the entire work is finished. A trained eye can recognize the proper degree of dryness from the sheen, which varies with different kinds of ink, but on the whole is always duller when the design is dry than while it still is wet. It is highly necessary that the design be thoroughly dry. It is possible to keep a designed plate for years without etching it, so long as it is protected against injury.
Etching is done in two ways, painting the fluid on and pouring it on.
The former method is less circumstantial, but is used only in coarser work, because there is always danger of damaging delicate parts of the design. It has the advantage, however, that any dirt caused by corrections will be removed. A mixture of three or four parts of water with one part of aquafortis is painted over the stone with a soft brush of fox- or badger-hair. The brush must be dipped continually because the fluid loses its power.
For the second method the stone is placed in a large wooden trough or box, provided with cross-pieces to keep the stone from the bottom. The acid, thinned down with thirty or forty parts of water, is poured over it. It is rather immaterial how much one may dilute the acid. Very weak solutions simply mean that the pouring must be repeated oftener. The fluid acts on stones according to their degree of hardness. Regard must be had, too, to the delicacy of the design, very fine lines being unable to resist etching that does not affect coarse lines.
Only slight experience is needed to recognize the effect of the acid. By looking at the stone sidewise and against the light, the growing elevation of the design can be perceived easily. When the fatty coating caused by the soap or turpentine wash has been etched away completely, and the water adheres equally everywhere, the stone generally is sufficiently etched to be ready for preparation and printing.
For the sake of easier printing, and also so that future grinding and any desired improvement may be done on the stone, there should be a little more etching, if the design is not too delicate. But if the design is very fine, the etching absolutely must not be more than strictly necessary, because the fine lines might easily be eaten away. Coarser designs can bear strong etching which often may reach the depth of a thick paper. But an inordinate amount of etching is not to be recommended, even if the design can bear it, because the edges of a deeply etched line are rough and take the color so strongly that it works into the cavities and is very hard to get out.
When the stone has been properly etched, clean water is poured over it to wash away the free acid. Then the work of preparing the plate with a solution of gum arabic in four or five parts of water can begin at once, or the stone may be set aside to dry, thus giving the finer parts of the design, that may have been most affected by the acid, time to adhere again to the stone and soak in, which can occur only in the dry state. This is entirely unnecessary with most pen drawings, but with brush and especially with crayon work it is of great value.
When the stone has been prepared with gum, it is set aside to rest for a few minutes. Then pour a few drops of water and exactly the same quantity of oil of turpentine on it, spread it in all directions uniformly and wipe the entire design off clean with a woolen rag. Hard ink, especially if it has been on the stone for some time, is more difficult to remove and a little more turpentine is required.
The stone should now be inked-in at once, because the turpentine, and with it all the fattiness, is liable to extensive evaporation, and then the stone will not take color well.
Inking-in of the pen designs is done as follows: A clean linen or woolen rag is soaked in clean water and wrung out till it is damp rather than wet. This is passed over the whole stone so that it becomes a little wet everywhere. Immediately after this dampening, the well-inked printing-roller is passed to and fro over the plate several times. The roller must be lifted frequently during this work so that the points of contact change. To lay the color on well and quickly, the roller should be held rather firmly in the beginning, well pressed down and used with a certain rubbing motion that will tend to lay color on the design sideways, so to speak. Then the roller must be allowed to roll to and fro a few times without much pressure, to spread the color and take away any surplus. Do not roll too long, till the stone dries, because then it will take dirt immediately. Should this occur, it must be wiped instantly with the damp cloth till it is clean again. If dirt is left too long, it will be extremely hard to remove.
Beginners usually wet their plates excessively to counteract this trouble of drying during the inking-in. This results in wiping away fine strokes, and the roller gets so wet that no good impression can be made till it has been dried sufficiently again. For this reason beginners should not use bath-sponge, because, though it is excellent, it leaves too much water on the stone unless one knows exactly how to use it.
Some printers put a little gum, others a little aquafortis into the water to wet the stone. Others use stale beer, or even urine. I consider all this unnecessary, if the stone has been prepared correctly and the color is good.
I have described the ink-rollers. I repeat that they must be uniform, soft, and elastic.
As to the inking-in color, I am not able yet to lay down a strict rule. All that I can say, as a result of my experiments and experiences, is:—
(1) The firmer the varnish in a color is, the cleaner is the work of inking-in.
(2) The same is true the more lampblack it contains.
But in both cases the finer parts of the work are easily rubbed away, and too much lampblack makes the lines squash the impression.
(3) The toughness or fluidity of the color must bear correct proportion to the power of the press. The harder the varnish, the more power is required in the press.
(4) Tough varnish is not so liable to squash under pressure, but if it has once been pressed into the spaces between the lines of the design it is not readily removed by the mere action of the inking-roller, and this causes more and more smutting and, finally, total ruin to the stone. Generally when a tough color has adhered too much, there is no other remedy than to clean the stone well with gum and oil of turpentine; and this, if done too often, damages the preparation and makes the impressions continuously poorer.
(5) Soft color spreads more readily under pressure, but is removable after each impression by merely dampening the plate.
(6) In using soft color, the paper may be kept damper than with hard colors.
(7) Soft as well as hard printing-color, if not mixed with the proper amount of varnish, has the property of producing poor, sooty impressions because of a defect called shading. Shading is caused as follows: If a drop of oil falls into a basin of clean water, a part of the oil will spread immediately. Now, a stone is wetted before inking-in. After the inking a considerable portion of dampness remains. If the ink is very fluid, it will happen often that a part of it will spread away from the design to the surrounding moisture, producing something that looks like a shadow around every part of the design. This does not occur instantly, as in the case of the pure oil, but gradually, so that it is not as noticeable when the swifter lever press is used as with the slower cylinder press or if the workmen are slow. If a stone can be dampened so exactly that with the last touch of the ink-roller the last vestige of dampness is removed, this is not likely to happen. But it is difficult to arrive at such accuracy. It is better to add enough lampblack gradually to the varnish to make it lose its elasticity, when the shading effect will cease.
(8) While shading is obviated largely through enough intermixture of lampblack or other coloring substances to take away the fluidity of the printing-color, this intermixture will cause other troubles. The finer places will not take the harder color so well, whereas at other places too much will be taken. Also an impression made with much lampblack will off-set more than one made with color in which varnish predominates. Neither will the impressions be so black. Experience teaches that a printing-color that has less lampblack will be blacker, because the sheen of the varnish will make the color strong and lacquer-like. I have tried to invent a kind of varnish that would not be so liable to shading and thus would permit a greater fluidity with safety, but lack of time has prevented me from exhausting the possibilities. I am sure, however, that it can be done, for I have found that the common linseed oil varnish can be made to lose its property of shading by admixture of fatty and resinous bodies. For instance, the addition of a slight amount of Venetian turpentine permits a greater fluidity. Very good is the following composition: Six parts linseed oil, two parts tallow, one part wax, melted together and thickened by boiling down and burning like the ordinary linseed oil varnish.
(9) The inner composition of the stone and the temperature have a considerable effect on the print and also react on the color. A stone, especially a porous one, has much less internal moisture on very warm, dry days. Then the dampening done before each impression often evaporates instantly and unequally, so that it is difficult to ink-in uniformly with a soft color or one lacking varnish, unless one wets the stone unduly, which, again, injures the impressions. In that case one must use a color that is firmer than should be used according to ordinary rule. It is also well, before printing from the stone, to lay it in clean water for a few hours, or overnight, so that it may soak in enough moisture to make it easier to dampen.
(10) If the drying of the printing-color is to be hastened, as is necessary with some work, a little finely powdered mennig may be mixed in. Finely powdered litharge of silver dries still better, but only a small amount of printing-color must be mixed with it, because it toughens within an hour. It will not keep for another day, because the mennig will dissolve after a while.
In printing from the pen design, the following must be observed:—
Even if the stone has been inked-in uniformly and well with a good color, the impression can be spoiled in various ways: if the paper has not been dampened as required by the nature of the color and the power of the press; if the pressure is not in proportion to the consistency of the color; if the scraper is not even, and if the leather is not properly stretched.
Therefore care must be taken in printing pen designs:—
(1) The paper must not touch the inked design till the scraper forces it down. It is not advisable to lay the paper directly on the stone. It should be in the printing-frame, which, as already described, should be so arranged that it will keep the paper at least one fourth inch away from the stone.
(2) The proper dampening of the paper is not a matter of the greatest importance in pen designs, so long as it is not too wet, in which case it causes squashed impressions, does not take color uniformly, and, if the printing-color is tough, will stick to the stone. In general, the rule holds good that the degree of dampening must be in proportion to the firmness of the varnish, and that a softer varnish permits increased dampening. Dampening is done chiefly to soften the paper, and the qualities of the paper dictate the amount necessary to a large extent.
(3) The tension of the press must be more powerful with hard printing-color and carefully graduated with soft color. Besides this, it depends—
(4) On the structure of the scraper. If it is not absolutely uniform and well fitted to the stone, more power is needed. Thus the defect often is corrected; but this may make the color squash and spread in other spots, therefore it always is better to correct any defects in the scraper. The sharper the scraper is, the clearer are the impressions, because then the whole force of the pressure concentrates on the smallest area. But usually the scraper soon becomes dull, and then the press must have more power.
(5) Insufficient tension of the leather also may produce poor impressions, especially if the color is soft and the paper very wet. Therefore as soon as impressions appear blurred and squashed, the leather should be tautened and well lubricated with tallow.
Now we come to an important matter, namely, the correction of errors. It does not happen often that a drawing or inscription can be made entirely without error, and it would be a great imperfection in lithography if these mistakes could not be corrected at once.
Errors may be observed before etching or afterward. Different ways of making corrections are required.
It is very easy to make corrections before etching. If the error is observed as soon as it is made, while the ink still is wet, it may be corrected by merely wiping out the defect with the finger. If the ink is dry, oil of turpentine is required. In each case the ink must be well removed so that it will not resist the etching fluid later. If only tiny spots are defective they can be corrected by delicate use of a sharp eraser. Defects that need merely to be destroyed without drawing anything else in their place may be scraped off with a knife or with pumice stone.
After the plate is etched, errors demand treatments that differ according to whether a defect or blemish is merely to be removed, whether something else is to be drawn in place of the removed part, or if something has been forgotten and is to be added. The area of the correction also makes a difference.
If it is only a matter of removing small defects or places, delicate erasure will do. The same, or polishing with pumice, is done if the area is larger. Then the corrected spots must be coated with a mixture of gum and aquafortis, using a soft brush very carefully that it may not touch any of the sound places.
If something new is to be drawn in, the process is different. Ink-in the stone very clean, and coat it with gum and water that is very thin and delicate. Let it dry. Then scrape the defective places away very carefully or grind them away by rubbing with pumice stone. Coat the spots cautiously with soap-water or oil of turpentine and clean off again as thoroughly as possible. (This coating is not necessary in the case of a few isolated small lines or points.) Now draw in your new design with chemical ink, and as soon as this is dry, etch the corrections carefully with a small brush and then prepare with gum.
The third case, where something has been forgotten, is treated almost the same way. If it is only a very small thing, the stone need merely be scraped carefully. Then the drawing may be put in, preferably with a thicker ink. If the area is large, the stone must be ground where the design is to be added, coated with soap-water or oil of turpentine, and then treated as explained before.
When the stone has been corrected and prepared for printing, it can be used at once or set aside for some length of time. In the latter case it should be inked with a firm color and coated delicately with gum solution. Then it can be held as long as desired. Coating with gum solution is advisable not merely for storing away, but for every interruption of printing that lasts more than five minutes.
If a stone has stood longer than a day without being freshly inked, it must be wiped off first of all with gum solution and oil of turpentine, that it may take the color well, so that the very first impression may be perfect. During the progress of printing, the following points are important: Uniform distribution of water, the same of printing-color, frequent inking of the inking-roller, and the very greatest speed possible.
In the main points the brush process is like that of the pen. The chief difference is that it is not possible to make the brush strokes as strong as those with the pen. Therefore, brush work does not resist etching so well and must not be treated too powerfully. Much depends on the treatment of the brush and the consistency of the ink. The brush does not permit such a flow of ink as does the pen, and generally requires one that is more fluid. A good brush ink is made as follows:—
Mix two parts of pure white wax and one part of good tallow soap into a mass not larger than a hazel nut. The ink loses its good properties quickly and should be made fresh day by day. Mix the two materials with a thick knife on a lukewarm (but positively not warm) stone, separate into small parts and moisten with rain water. As soon as the water has softened the mass a trifle, add as much lampblack as will lie on two knife points and mix the whole mass together once more till it is thoroughly mixed and quite firm. When required, a bit of this is rubbed down in a clean saucer with rain water.
As a better flow of ink is needed for brush work than for pen work, it is evident that it would not be requisite to treat the stone with soap-water and oil of turpentine, as for pen work. However, it often pays to make certain fine lines with the pen, and therefore it is better to combine both processes and prepare the stone as for pen work. It is well, however, after drying the coating, to rub it very gently with dry sand, which will not make the pen strokes flow to any extent and still will prepare the stone so that it will take the brush strokes well and not make necessary such strong etching.
If a brush design is to be etched in high relief, for ease in printing or for durability, it must be etched only to the extent absolutely required at first. Then it must be prepared with gum and inked-in with good acid-proof color. Set it aside for a while, that the color may concentrate so that it will resist the acid well, and then etch the stone to the desired degree. After etching, wash with water, coat with gum and put aside to dry. Owing to this latter procedure any fine parts that may have been unduly affected by the acid will adhere to the plate anew and it can be printed then like a pen design.
If pen and brush work are to be combined on a stone, and absolute certainty is desired, that even the very finest lines shall not suffer from etching, the following process will serve:—
Over the cleanly ground plate pour a solution of weakened but pure aquafortis, about forty parts of water to one part of aquafortis. Repeat this several times. Then pour a great deal of water over the stone, to wash off all acid, and let it dry. Pen as well as brush work is easy on such a stone, by using the proper ink for each method. When the work is finished and dry, the stone is merely coated with gum solution. After a few minutes it can be inked-in with acid-proof ink and treated as described before.
II
THE CRAYON METHOD
The fat of the chemical ink penetrates the stone in dry form as well as in fluid form, and makes the plate receptive to printing-color. If the dry ink is cut into long pieces and sharpened, it can be used much like lead or black crayon. If the stone is ground very smooth, the work can be made quite fine and resembles that done with fluid ink. The crayon, however, wears away too quickly. If the stone is ground rough, so that instead of a polished surface it has one resembling rough paper, the crayon work appears as a mass of dots that are coarser or finer according to pressure with the crayon, and produce an effect similar to crayon designs on paper. As almost every artist and painter knows how to use crayon, no particular practice is required for working on stone, and there are no obstacles such as the difficulty of using the steel pen.
That crayon work on stone is capable of high perfection, and that it can represent the essentials of a painting in a manner scarcely to be excelled by the best copper-plate engraver, has been demonstrated by many successful productions. Add to this that in no other style can one work equally fast, either on copper or stone, and we see that the crayon method is a genuine advantage for the art.
For crayon work the stones must be uniform and hard. They must either be new, or, if they have been used, they must be ground so thoroughly that all traces of fat are destroyed and removed absolutely to a degree where it is certain that they will not appear again and take color, even if the stone is etched only lightly. As soon as the plates have been ground true, they must be grained by strewing some fine sand or powdered sandstone on them and rubbing in all directions with a small piece of limestone. The work can be done dry or wet. Soap-water is best. It gives the stone a handsome grain. Practice is demanded to get good results without scratching the stone. The artist must decide for himself what grain he needs. I think that it would be good if the artist himself were to grain the stone in varying degrees according to the need of his design. For instance, a coarser grain might be good for foregrounds.
As soon as the stone has been grained, it must be cleansed perfectly from dust and dirt. It is best to pour clean water over it and wash it with a clean rag. The dust and sand must all be removed, otherwise they will not let the crayon reach the stone where it is used delicately.
When the design is finished, it should be set aside for a day, that it may take good hold of the stone. It does no harm to let plates rest for years before etching. Etching must be done by pouring. Painting the etching fluid on is dangerous because of the danger of taking away fine spots. About one hundred parts of water are used to one part of aquafortis. Everything depends on not etching a bit more than necessary. It is best to etch the coarser parts specially with a small brush and stronger etching solution, and it is very good to wash the stone with clean water after etching and let it dry completely before coating with gum.
When the stone has been prepared, it should not be cleansed at once with oil of turpentine, but should be inked-in first with a light printing-color. Only after it has taken this well should it be cleansed of the crayon and treated to a firmer color. In the first inking-in there should be very little pressure with the sponge or wet cloth when dampening it, as the lightest parts of the design are easily rubbed away before they have taken color. If such parts should vanish, the easiest way to restore them is as follows:—
Coat the plate with gum solution and wipe with a clean dry cloth till it is perfectly dry. Then take a flat, knife-like instrument of steel, which is cleanly ground so that it has no nicks or other defects that might injure the stone. Scrape with moderate pressure to and fro over the defective places, but only so that it touches the elevated points and not the surface of the stone itself. Smear a little fat, such as linseed oil varnish, over it and wash this away again instantly with gum solution. Generally the parts all reappear very nicely when the stone is inked-in again.
A second kind of correction is as follows: Ink the stone with firm color, wash it well with plenty of pure water and let it dry. Now redraw the lost places with crayon.
Printing crayon work is the most difficult of all lithography, but can be done perfectly if all necessary precautions are taken. These are mainly: (a) proper dampening of the paper; (b) perfect dampening of the stone;—too much meaning that the fine points will not take color well, too little making the stone smut easily; (c) good stretching of the leather, industrious lubrication, and an underlay of taffeta; (d) a good, finely mixed inking-color that will not shade off in printing and yet does not contain too much lampblack; (e) soft and well-dried ink-rollers; (f) proper tension of the press; (g) utmost possible speed in printing. The latter aids enormously, because the stone does not get so much time to dry out.
Aside from the spreading and running-together of the darker parts, one of the commonest faults of crayon work is that it is very liable to get a tone, which spreads over the whole design like a veil; or that the designs lose their firmness and appear "monotonic" because the shadings spread and thicken. The first fault comes from weak etching or from oil that was rancid when it was used to prepare the varnish. The latter fault makes the color adhere and smut the stone. The same fault is developed if the printing-color contains soap, which some printers mix into it for better adherence. It can occur also if the stone has lost its preparation owing to frequent cleansing and strong rubbing with a dry rag that is inky. Even strong rubbing with clean water can cause it if the rag contains fats.
As to the "monotonic" effect, it is frequent, and I have learned that it can be caused in two ways, namely, if the color is squashed continually during the print, which makes the stone sooty; or if the color spreads, as, for instance, during the night or during the noonday rest. The stone is prepared only on the surface. In the pen style, all lines are prepared on the sides also, so that they cannot spread because they are considerably more elevated than the crayon designs.
If a crayon design dries after printing and is not coated properly with gum, the color is liable to spread away from the design and give the plate the before-mentioned tone. Even if it is coated with gum, the color will spread, at least in the inner parts of the stone; and as soon as the very thin surface has been at all wiped away by rough usage, the underlying fattiness will appear gradually, and begin to take color.
Both faults of crayon work, namely, the taking of tone and the development of a "monotonic" condition, can be remedied by inking the plate for a while with a firmer color. If this does not help, the following must be resorted to: Ink-in the plate as well as possible, lay it in the etching-trough and pour over it very weak aquafortis once or twice. Then wash it with pure water and paint the gum solution over it. The etching must be done with great caution, with a solution so weak that the acid is scarcely perceptible. If the plate is to be saved at all without extensive corrections and re-drawing, this is the best way. If it is done correctly, it harms the design so little that I advise it even when the plate looks quite well, but has been standing very long after the first printing.
I have etched several crayon designs over again, and rather extensively, to make them more durable and facilitate printing, and with good success. This gives the further advantage that corrections can be made at the same time.
The correction of crayon designs, that have been etched already and used for printing, always has been so difficult a task that few have succeeded. This has led me to give the matter my best attention; and I hope that the following rules, based on many experiments, will show the way, at least, even if they do not produce absolute results.
When a copper-plate engraver has partially finished his plate, he can have a proof pulled to enable him to study his work. Then he can make corrections as he pleases,—an advantage that the stone worker has lacked hitherto.
To produce an impression that shall be faithful to all the beauties of a crayon design is a matter dependent on so many trivial details that of the many hundred crayon designs that have been produced by lithographers since the origin of the art, hardly one has realized the designer's hopes and ambitions. The commonest fault is that the more delicate parts of the design print too light and the heavier ones too dark, thus destroying the balance of tones. The lightening occurs because the finest parts of the design have lost their power of taking printing-color. The darkening occurs because the closely shaded parts flow together, either because the etching has not made enough white space between the points and lines or because they are squashed in the pressure of printing.
From this, two other faults may arise, that become visible after inking-in the plate: The first is the appearance of white dots, sometimes pretty large. The second is that black dots and smut-marks appear.
The white dots are caused by speaking during the work, and thus dropping spittle on the plate. If the spittle is mucous, the plate covers itself there with a fine crust that resists the chemical crayon so that it does not soak into the stone and is wiped away by the inking-in. If the spittle is fatty,—for instance, if one has eaten anything greasy,—the dots that appear will be black. The same results from touching the plate with fatty hands. Sometimes a whole picture of the fingers and skin will appear on the impression.
Let us suppose that after inking-in, a plate shows all these faults: the finest shadings vanished entirely, the darker places run together, white and black dots and smut-marks so that the plate has become useless in every respect. Can this be remedied? If so, how?
I answer that it can be remedied in every point; but that the artist himself must decide if it will not pay better to do the whole design anew.
The second question I answer as follows:—
Before everything else, it is necessary to remove all that should not be on the stone, all smut-marks and black dots; and where the design has darkened, white points or lights must be graved-in. To accomplish this, the stone is inked-in first with a firm acid-proof color, and over this with a lighter one. Then erase or grind away the dirt that is outside of the design and that would dirty the margin of the printing-paper. No erasing or grinding must be done within the design itself because then the grain would be destroyed and the necessary drawing could not be done as it should be. Therefore the faulty parts must be removed by engraving, with a more or less sharp needle of good steel, so that what remains looks quite like a good grain. A little practice will show that this work is not at all difficult and can be done quickly. Places that have run together can be cleared and made transparent and clean in a few minutes. If certain points have become too large, they can be corrected by engraving a white point in their centre or by engraving a line through them.
Here I must note that parts of crayon designs thicken sometimes because the crayon has slipped in drawing, without leaving traces perceptible at the time. If the etching is weak, it may happen easily that this place takes printing-color. Skillful engraving may not only correct the defect, but actually gives the design a beautiful tone and power such as cannot be easily produced by the crayon itself.
When the plate has been cleansed thus of all surplus and blemishes, weak aquafortis is poured over it several times and then it is coated with gum. After a few minutes it is inked-in with fairly firm color. Then it will be seen that the design is clean, but that all the parts that were too light are not darker, but perhaps even lighter, having been affected by the etching. To remedy this, coat the stone with gum solution and then wipe it off with a dry clean rag so thoroughly that only a thin film of gum remains behind. To judge this better, it is well to mix a little red chalk with the gum. When the plate is wholly dry, take a knife-like tool of steel as described before, and scrape the defective parts under moderate pressure, without injuring the elevated points of the design. Great care must be taken during this process to let no moisture, not even the breath, touch the stone, because that would produce the very opposite of what is aimed at. When all faulty places have been treated, a little tallow or linseed oil is smeared over the plate and then washed away well but gently with thin gum and water. If this manipulation has been done accurately, the lost parts of the design will appear when the plate is inked with a somewhat softer color.
Those who fear that they do not possess the skill necessary for this rubbing-up of the defective parts may attain the object by re-drawing them. The stone must be washed off first with a great deal of very pure water and the crayon must contain much soap. This kind of correction must be finished as quickly as possible and the stone should not be set aside for any length of time without a gum coating. If the corrections are extensive, it is better first to ink the stone well with acid-proof color and then to wash it in pure water and let it dry. Then if it is inked-in after the design is finished, and if weak aquafortis is poured over it and it is prepared with gum, it will keep for several months.
Slight blemishes, white specks, etc., can best be corrected by gentle touching-up with crayon during the proof-printing on the wet plate. It is understood, of course, that one can also work with pen or brush in a crayon design that has been already etched. Parts that are too dark can be made lighter by passing over them a few times with a brush dipped in weak aquafortis and then re-coating with gum.
These are about the best ways for correcting a crayon design that proves after etching to be imperfect.
I close with the following:—
(1) The tanners of Munich manufacture an inking-ball, made especially for printing, of sheepskin, such as I could not obtain in other places, like London, Offenbach, and Vienna. It is not white like alum-dressed leather, but yellowish, and the oil has not been completely washed out. I have had dogskin and thin calfskin worked in the same way and have found them even better, because of their greater durability. If a roller is covered with this leather, so that the side that was hairy comes outermost (not innermost as many do), it develops a decided property of taking-on color, probably because of its smoothness and elasticity. This aids much in spreading the color uniformly over the stone. The property is increased if the roller is dampened slightly before being inked; but on the contrary, if the stone is kept too wet, the constant moisture will gradually prepare the roller, so to speak, and it will take less color and let it go quickly, thus inking the stone badly.
If a roller has been used a long time, it loses its elasticity and softness and becomes useless for fine work. Still worse is a roller that has hardened from the drying of the ink. It is surprising to see what a difference it makes if one has worked for a time with a poor roller and then replaces it with a good one. It is almost impossible to believe that the new impressions come from the same stone. I am inclined, therefore, to believe that the quality of the ink-roller has more effect on good impressions of crayon and fine pen work than even the quality of the printing-color.
As stated, it is well to change rollers frequently, and it is wise to clean them with linseed oil or butter after use to keep them soft and tender. In working on crayon designs of superior value I advise the use of new rollers.
(2) It has been remarked before that the color of the stone often deceives the artist as to the values and proportions of his work and that the designs always look better on the soft-colored stone than they do on the glaring white paper. This observation led to printing on paper tinted like the stone, and the results fulfilled expectations. There were difficulties however. The very best quality of this paper is extremely dear, and other qualities had the property of dirtying the stone, on account of the coloring-matter used for tinting them. Therefore the attempt was made to print the design on white paper and to color it afterwards. Here, too, there arose many inconveniences, so that at last there came the thought of laying a yellow tint over the impression by means of a second printing. This method proved to be not only the most economical and quick, but it had the further advantage that the margins of the paper could be left white, thus enhancing the value of the design. Hardly had it been used with success a few times before Herr Piloty conceived the idea of printing the high lights into the design with white printing-color, so that the impressions would resemble actual drawings. My experiments toward that end did not result satisfactorily, because no white oil color will print well enough; and I proposed that the high lights be engraved into the tint plate and thus permit the original white of the paper to show. So there came that kind of crayon impression with one or more tint plates, which has become so popular that various art connoisseurs hold it to be the triumph of the lithographic art.
To make and print these tone plates, I have thought out many ways; but as I am sure that they will suggest themselves to those who have grasped my text-book, I will describe only the best of them all.
Take a stone of good average quality, the best not being essential, and grind it as for crayon work with a grain not too coarse. When it is clean and dry, cover it uniformly with the following chemical ink, which must be laid on so thickly that it surely will resist the aquafortis sufficiently, yet not so very thickly that it will hinder the drawing-in of the lights later on.
The chemical ink for use on the tone plates is made of four parts wax, one part soap, and two parts vermilion. The two first materials are melted in a clean vessel over a moderate fire and then the vermilion is stirred in.
A piece of ink as large as a hazel nut is rubbed down in a clean coffee cup and then dissolved in rain water till it is just fluid enough to lie evenly and nicely on the plate when applied with a soft brush.
When the stone thus has been painted red, it must be permitted to dry thoroughly. When it is dry, a strong impression of the design is made on sized but well-dampened paper with a printing-color rather soft than firm. Before the paper has a chance to dry and thus to shrink, the red stone is placed in the press and the impression is laid on it face down. Use moderate pressure. The drawing will transfer itself to the red surface, but the paper will stick. Wet it with weak aquafortis till it is completely softened and permits itself to be removed. Care must be taken not to spoil the drawing by violent wiping and rubbing.
This method is easier if a special transfer paper is used. Coat well-sized, very clean paper with a thin paste of starch such as laundresses use for stiffening linen. This paper must not be dampened very much, because then it will not take the impression well. It also is removed from the tone plate by washing with weak aquafortis and it yields very easily, because the paste lets go of the color readily.
When the design has been transferred to the tone plate, take good iron instruments and remove the wax surface wherever the high lights are desired. As the stone is ground rough, the scraping will produce only small specks at first, because the instrument will touch only the relief points. The more the scraping proceeds, the deeper it will go, till at last one reaches the bottom of the coating and thus obtains a white light. Experts can so manipulate the tint plates that the lights will be graduated from the softest to the most glaring.
As soon as the lights are drawn in, the margins of the drawing are scraped the same way. Then the plate is treated to several washings of pretty strong aquafortis, about twenty parts of water to one part of aquafortis. After coating with gum, it is ready for printing.
The most important requisite for this printing is a good arrangement that will insure an exact register of the second impression with the first, that the lights may appear exactly where they belong.
To achieve this, the practice used to be to draw two register marks on the stone holding the original design, which were transferred to the tint plate with the rest of the design. When the first impression was made, the printed paper was cut away exactly at the marked points, and laid accurately, on the tone plate, being guided by the two marks there. This was effective, but it had the fault that the paper had to be trimmed off carefully for each impression and that the slightest inaccuracy spoiled the register. However, it is very useful for printing proofs.
It is far better to have a printing-frame that is so fixed that it will never shift its position in the slightest degree. To this is fastened a little movable frame that has two steel needles whose position is adjustable at will. Lubricate the leather inside with wax and lay a sheet of white paper on it. See that the tint plate is so fastened in the press that it cannot stir out of place. Make an impression and take care especially that the two register marks print off well. Now set the needles in the little frame so that they will be exactly over these two marks. If, then, an impression of the design is laid on so that the two guiding-marks on it come exactly under the two needles, it will, of course, register perfectly. Of course the little frame must be so adjusted that it can be folded back out of the way before each impression, and the printing-frame must hold the sheets of paper so that they cannot move.
To color the tint plate, use a firm varnish tinted with umber, or any other color that will give the desired effect. New rollers are best, insuring a fine, even, unspotted tone.
(3) In rough-grinding the stones, it is difficult to prevent scratches and furrows caused by the coarse sand. No design of value should be made on such a stone, but if one is used, the defects should be touched up with chemical ink and a fine brush, as crayon will hardly do it.
(4) As the delicate places in crayon work are not durable, etching having the property of reducing the light portions and darkening the darker ones, I tried the method of drawing the lighter portions on a separate stone in rather stronger manner and printing from it with paler ink. The success was so great that I hope in time to produce true masterpieces with the aid of skilled artists, and here call attention to it in advance.
(5) After learning how to make a second impression over a first one, it is not difficult to pass on to printing with several stones and from that going on to color-printing. In the early days of my invention I tried color-printing with a crayon plate and had the best success by using stencils such as are used by the painters of cards. On oiled stiff paper I made as many impressions of a design as there were to be colors. Then all that was to be red was cut out from one stencil, green from another, and so forth. Then the stone was wetted, the stencil laid on it and the uncovered parts of the stones inked-in with the right color. After all the colors had been applied, I made the impression, which generally looked neat enough, but still resembled a sketchy drawing rather than a painting, because no color except black, zinc red, and dark blue permitted itself to be printed strongly enough. But by using several stones, each of which can be designed and treated according to the necessities of color, impressions can be made that resemble the English colored copper prints very closely, especially if the crayon and pen or brush methods are united.
(6) A stone plate may be etched so that it will have the roughness needed for crayon work. Grind it as clean and smooth as possible with pumice, pour aquafortis over it and coat with gum. Wash it well in water and dry with a clean cloth. Coat it very thinly but uniformly with tallow into which is mixed a little lampblack, so that one can see if the coating is perfectly even. With a small ball or roller covered with fine cloth, roll or pat the stone till it has a very uniform tone. Now pour a little diluted aquafortis on one end as a test to see if it penetrates uniformly through the fatty coating. Practice is needed to hit just the right thickness that the tallow coating must be. It must be thin, and yet sufficiently thick to resist the aquafortis somewhat, so that it yields only at those places where the roughness of the cloth on the roller has removed it more or less.
If the test is satisfactory, make a raised border of wax around the stone and pour the aquafortis solution on it. A solution of forty parts of water to one part of aquafortis is better than a stronger one because the stones are more equally attacked. As soon as the resulting bubbles are as large as the head of a small pin, the etching fluid is poured away quickly and replaced with pure water to get rid of the bubbles. Pour away the water and apply etching fluid again. Repeat this four or five times, according to the grain desired, and in the end wash the stone well with oil of turpentine to remove all fattiness. Then it must be washed with weak but very pure aquafortis, followed by a great deal of very pure water. After cleaning and drying very carefully with a clean rag, it is ready for use; and if the work has been well done, a grain will have been produced that is prettier and much more even than can be produced by rubbing with sand.
(7) The instructions given here teach how to draw on a stone that has been prepared beforehand with aquafortis and gum. This is not in the least inimical to the durability of the design if only the union of the gum with the stone has been destroyed again by washing afterward with diluted but pure aquafortis and every trace of this acid again has been removed by copious washing with pure water. If there is a considerable amount of the soap in the crayon, the good result will be greater than with an entirely clean stone, because, since it has already been etched twice, the etching after the design may be very limited, so that it is not harmful to even the most delicate shadings in the design.
(8) Some attempts made by me to etch crayon designs more powerfully than usual proved that the more delicate places would suffer, but if I rubbed them up with a flat knife as described before, they appeared again and I had the advantage that the whole plate was much better prepared than it is with weak etching.
(9) If a crayon plate is spoiled in printing through carelessness or lack of skill, the rules for remedying the trouble are the same as those named for pen work, and the judgment of the worker must decide which method is the most applicable. In general, it may be assumed that the best remedy for blurred spots is to draw them over again with crayon; and for smutted parts the best is to apply firmer printing-color, or to cleanse with oil of turpentine and gum and afterward ink-in with acid-proof ink, and then use light etching with weak aquafortis followed always by coating with gum and water.
III
TRANSFER AND TRACING
In the pen and crayon method all the lines that are to take printing-color are drawn directly on the stone with a fatty preparation. But lithography has a unique way of transferring to the stone a drawing or inscription that is first put on paper with the fatty substance. This is possible only for lithography, and I incline to the belief that it is the most important of all my inventions. It makes it unnecessary to learn reverse writing. Everybody who can write on paper with ordinary ink can do so with the chemical transfer ink, and this writing can then be transferred to the stone and manifolded indefinitely. In Munich and Petersburg this method has been introduced for government work. The measures adopted in council are written during the session by the secretary, with chemical ink on paper, and sent to the printery. Within an hour impressions are ready to distribute among the members. I am convinced that within ten years every European Government will have a lithographic establishment.
In war the method would have a great value. It would replace the field printery, and it permits greater speed and secrecy. The commander need merely write his orders himself and have them printed in his presence by a man who cannot read, to be sure that his plans will not be betrayed. The engineer officers can draw plans and have them circulated among the officers who need them.
Authors and scientists will find the method to be the means of circulating their works in manuscript very cheaply.
Even artists will respect the method when its gradual perfection enables them to draw their pictures on paper with ink or crayon and reproduce them.
Not from boastfulness, but from conviction of the importance of the method, have I thus recounted its advantages. I could fill a whole book with detailed explanations. I wish to gain friends for the method, that it may be improved to its ultimate degree by skilled artists.
The chemical ink used for the paper may be soft or firm. The paper may be specially prepared or not. The stone may be warm or cold. The design leaves the paper entirely and clings to the stone, or does so only partly. To describe all this would take too much space. I will describe only the method that I consider best, namely, a method under which the work is done with a soft ink, and transferred to an unwarmed stone. This is the quickest and surest, and has the advantage of not spoiling the original.
In a clean coffee cup rub down a piece, as large as a hazel nut, of the chemical ink described under the heading "[Transfer Ink]" in an earlier part of this work. Dissolve with rain water or soft river water. The amount of water is determined according to the need for fine or coarse work. In the latter case, the ink should be thinner, that there may not be too much ink in the design after it dries.
While the writing or design is drying, select a stone that either has not been used before or at least has been thoroughly ground off, and grind it down once more with pure and dry pumice stone without water, until it is certain that all parts of the surface have been rubbed down so thoroughly that the stone may properly be considered a new one. Clean away the dust with clean paper, fasten the stone in the press, examine the scraper to make sure that it is even, adjust the press for the proper pressure; in a word, do all that is necessary for good impressions. From this time on the greatest care must be taken not to touch the polished stone with as much as a finger, not to mention keeping grease and dirt away from it.
As soon as every point in the design on the paper is perfectly dry, wet it on the reverse side with a sponge dipped into weak but pure aquafortis until the paper is quite soft. Lay it between waste paper sheets for a time, to prevent it from pulling out of shape and to remove the excess moisture. It must be soft, but not wet, when the impression is made.
Lay the paper face down on the stone. On it lay two sheets of dry waste paper, then an equally large piece of taffeta, another sheet of waste paper and make the transfer print with a moderately swift motion of the press, which must have more tension than is used for ordinary impressions. The power of a lever press is insufficient for larger stones, and a cylinder press is required.
After a few minutes the stone is withdrawn from the press, the paper is lifted off and the stone permitted to dry for a minute. It is better if one can wait longer. Then put it into the etching-trough, and pour over it, quickly and only once, a clean but weak solution of one hundred parts of water to one part of aquafortis. It is necessary to be skillful enough to cover the whole surface with one application. Then the stone is washed by pouring pure water over it, and, if time permits, set aside to dry. If time is limited, the gum solution to prepare the stone can be put on at once. Now the transfer is on the stone, properly etched and prepared. To make clean impressions, however, the printing-color must first be rubbed on, then the stone must be inked-in with acid-proof color and after that undergo another etching, a trifle stronger.
To rub on the printing-color, rub a little acid-proof color into a piece of clean linen or cotton, so that it is well permeated but not thickly covered. Rub this rag gently to and fro over the transfer while the gum is still on it, till every part of the design is nicely inked. This rubbing-in of color is an important part of many of the processes that will be described later.
Now clean the stone well with water, ink-in with acid-proof ink, and etch it again as has been described several times. Then it is ready for printing. The last etching is not necessary if only a few impressions are desired.
Transfer is applicable not only for pen designs but also for crayon. The crayon used for the purpose should be softened a little with tallow, or, if the harder crayon is used, the stone should be warmed when making the transfer. But it must not be inked-in or have color rubbed on, until it is quite cold again. For crayon transfer the paper used generally is fine drawing-paper. It must be wetted with somewhat stronger aquafortis that it may release the crayon more readily. The rest of the process is the same.
Besides these two methods, the transfer process can be used for all products of the book-printer's art, type as well as wood-cut. A freshly printed sheet can be transferred directly to a stone, especially if the printer has used our before-mentioned acid-proof ink instead of his ordinary printer's ink. To get a perfectly clear transfer it is necessary merely to see that the printer does not use too much overlay, which would stamp the type too deeply into the paper; and that before trying to transfer the printed sheet to the stone it is subjected to gentle pressure in the press to free it from all inequalities. To do this without at the same time risking any loss of ink which might subsequently weaken the transfer, the sheet is well wetted, laid on a clean, wet stone that has been prepared so that it will not have any inclination to take color, and subjected to a very slight pressure, the press being used with almost no tension. This makes the printed sheet beautifully even. Then if it is transferred to a stone properly prepared as described before, the transfer will be perfect.
Even old book pages can be freshened up and transferred. I have spoken already of those that are on unsized paper. With prints on sized paper the method is as follows:—
Make a paint-like mixture of fine chalk and starch paste. Thin it down with water and paint the sheet. Dip a bit of linen rag into a thin color made of thin varnish and tallow tinted with vermilion. Touch-up the wet paper with the rag till every bit of type has taken red color. Pour clean water over it and touch-up the paper everywhere with a ball of fine cloth stuffed with horsehair. This will remove all surplus color. Continue this till the type matter is only faintly red. Then the paper must be washed very thoroughly with many pourings of water and laid between waste paper sheets to remove all surplus moisture. The transfer and so on must be done then as in the other cases.
Good transfers can be made also from a copper-plate engraving if the copper-plate impression is made with our acid-proof ink. The ordinary copper-plate ink is not so good. It will be self-evident that designs on stone can be transferred and reproduced the same way.
The tracing process has the property in common with the transfer process that it transmits only a small amount of fattiness to the stone and requires subsequent rubbing-in of color to give it strength.
Coat a piece of thin and clean vellum paper with tallow and lampblack and wipe it off again as neatly as possible, so that there remains only a thin film, which will not smut the stone when laid face down, unless pressure is exerted. Now draw on this with a clean English lead pencil that contains no sand, or with a composition of lead, zinc, and bismuth, and the pressure will force the design on the stone and transfer its fat, which then penetrates the stone and will give impressions. In preparing a stone thus made, greater care in etching is necessary than even in the transfer process. Very weak aquafortis solution must be used.
The process is something between pen and crayon work. It is quite applicable for sketches and pictures that are to be illuminated.
IV
CONCERNING THE WOOD-CUT STYLE
For this purpose, the stone is coated completely with chemical ink on the places where this style is to be used. As soon as it is dry, the lights are drawn into it with a steel engraving-needle that is ground to a sharp or broad point according to requirement. Those parts that are to be very white, with fine lines and specks, are best drawn in with the pen. Thus the wood-cut style differs from the ordinary pen design chiefly in character and in the treatment of the darker parts. Its practice is much easier on the stone than on wood, and it can be combined with crayon work. Etching, preparation, and printing are the same as with other styles.
V
TWO KINDS OF TOUCHE DRAWING
One of these resembles the wood-cut style in method but in effect approaches copper-plate work. The stone is grained as for crayon, etched, prepared with gum, cleansed with water, coated well with soap-water, wiped, dried, and finally coated with a thin, colored covering of fat, by either coating with acid-proof ink or with hard chemical ink.
This first etching and preparation are required to prevent the fat to be applied afterward from penetrating too deeply into the stone, so that it may adhere only to the surface.
Now the design is made on it with a steel scraper. The manipulation is like that for making tint plates. It demands greater care, however, and better etching.
The completed design is etched (phosphoric acid being best) and coated with gum. A few drops of oil of turpentine are poured on and all the color is wiped away with a woolen rag, but without any rough rubbing. Then the plate can be inked-in with fairly firm acid-proof ink.
The second method would excel crayon work if it were perfected. I have advanced pretty far with it. It is an imitation of the ordinary wash drawing which is done with a brush and dissolved Chinese ink on paper.
The stone, which must be very clean and free from all fat, is grained, coated with soap-water, cleaned with oil of turpentine, and dried. Then a hard chemical ink, which may contain a little more soap than usual, or the ink described for brush work, is dissolved in pure rain water and used on the stone with a brush just as it would be used on paper.
When the design is finished and very well dried, the entire surface of the stone is rubbed gently with a fine cloth, in order to perforate the color with tiny holes everywhere. As it will perforate more readily in the parts where the ink has been laid on thinly, the succeeding aquafortis will eat through there more easily, and thus the etching will correspond nicely with the tones of the design. It is necessary, however, to know the strength of the acid and the resisting power of the ink very accurately. It is well to experiment and write down the best proportions. In any case, the etching fluid must not be too strong and the etching must not be done by pouring or brushing, but in the copper etcher's manner, by framing the stone with wax so that the fluid will lie on the stone. As soon as the resulting bubbles reach the magnitude of a pin's head, the fluid is poured off instantly and then poured on again till the bubbles reappear. How long this must be continued depends on the strength of the ink.
It is understood, of course, that the etched stone must then be coated with gum.
VI
THE SPATTER METHOD
This speedy and easily executed style surely will come into wide use soon. It is done as follows:—
The outlines of a design are laid on a stone prepared for pen work, by tracing. Then they are traced again, say four times, on sheets of paper. On each sheet everything that falls into the category of one of the four chief tones is cut out with a sharp penknife so that the four sheets are like the stencils of card painters. Now the chief lines of the design are made on the stone with chemical ink, using either brush or pen. Lay one of the stencils on it exactly, weight it that it may not move, and perform the operation of spattering.
This is done by dipping a small brush, such as a clean toothbrush, into chemical ink and scraping it with a knife so that the ink is spattered over the stone. Care must be exercised not to have too much ink in the brush, for fear of blots or over-large spattering. After practice it will be possible to produce such fine and uniform dots as cannot possibly be produced by the pen. After the desired grade of shading has been achieved, the stone is permitted to dry. Then the second stencil is laid on and the operation repeated till all have been used. If enough stencils are made, the whole design can be made by spattering. It is not necessary, however, to make many, as the design has to be finished up by hand afterward anyway.
This finishing-up is done first with the engraving-needle, which opens and decreases all dots that are too large, and then with the pen, which brings out the true proportions of the various tones.
VII
TOUCHE WITH SEVERAL PLATES
This really is only a process of using many tint plates. It makes splendid effects possible, equal to any produced by an artist with Chinese ink, and deserves the attention of all artists, especially as it is the easiest and quickest of all methods, even though it is a little circumstantial in the printing.
Draw the outlines of a design on the stone in chemical ink with pen or brush, and then make four, five, or six transfers on stone plates prepared for pen work. Register marks must be on the design. Now draw-in the darkest parts on the first plate, the less dark ones on the second, the lighter ones on the third, and so on till the whole design is finished. The work is best done with a brush. One or more of the stones may be designed with crayon; but the number of stones designed with ink must be greater, in order to make the grain of the crayon designs unnoticeable.
The etching is done as in pen work. For each stone the printing-color is chosen according to the tone of its design. Of course particular accuracy is vital; but the artist should not permit the apparent difficulties to frighten him, as he will see very soon after trial that no other method produces such beautiful results.
VIII
COLOR-PRINTING WITH MANY PLATES
This method, in which the various colors are drawn on several stones, either with pen or crayon, resembles the one just described.
According to treatment the impressions will resemble a painting, a copper-plate engraving in color, or an illuminated copper-plate engraving, if the color stones are used merely to lay colors over a design already printed in its entirety in black.
The whole process is so like the preceding one that I need merely recount the colors that I have found serviceable for the purpose.
Red. Vermilion, red lake of cochineal, fine madder lake, and finally carmine if it is mixed first with Venetian turpentine before being combined with varnish, as otherwise it inclines to separate from the varnish and unite with water, staining the whole printing-paper red.
Blue. Berlin blue and mineral blue. Use only a small amount, sufficient for a few hours. These colors dry quickly, and, besides, make the varnish too tough, so that they must be thinned down from time to time with a little linseed oil. Fine indigo is very good, also a blue lake that is made of logwood and verdigris. This latter is not durable in sunlight.
I have had no success as yet with green or yellow.
Verdigris is difficult to manipulate because it smuts the stone easily and does not tolerate many mixtures. Schweinfurther green, one of the new colors, is much better in all respects, but not dark enough. Mixtures of yellow lake with indigo or mineral blue are not very durable. Golden yellow ochre with mineral blue or indigo does not produce a pretty green, and King's yellow mixed with blue is handsome but not durable. Neapolitan yellow and the newer chrome yellow with blue produce a green that is not dark enough.
I have obtained the handsomest and darkest green by printing the design blue first and then printing over it a yellow plate, so that the yellow lay over the blue. By using Berlin blue and fine ochre a fairly handsome color is produced. On account of its loss of color in water, ochre cannot be used unless Venetian turpentine is first mixed with the varnish.
A handsome and at the same time dark yellow is equally hard to obtain. Till a good color is invented, we must content ourselves with ochre, Terra de Sienna, Neapolitan yellow, mineral yellow or chrome.
This printing with various colors is a process for which the stone is superior; and it is susceptible of such perfection that in future true paintings will be produced by its means. My experience convinces me of this.
IX
GOLD AND SILVER PRINTING
This process is useful for decoration.
Those parts of the design that are to appear in gold or silver are drawn with chemical ink on a stone prepared for pen work. After the drawing is dry, it is etched and prepared in the usual way. The printing is done with a silver gray color of firm varnish, fine crayon and a very little lampblack. The paper must be entirely dry and very smooth. Soon after the impression has been made, the printed parts are covered with silver or gold leaf such as is used by gilders. It is pressed on slightly with cotton, that it may adhere, and then a sheet of paper is laid over it. Then the second impression is made, treated the same way, and so on.
No more impressions must be made than one can cover with silver or gold in two hours. If the ink is on the paper too long, it will draw in and not take the metal well. After gilding or silvering, the sheets must lie for some hours or till the next day, that the ink may take perfect hold of the paper, so that, in the succeeding pressing, it will not penetrate the metal and make it look sooty. The pressing is done by laying six or eight impressions on a clean stone under the press and passing them through as for printing, with the proper tension. This tension must be adjusted according to the firmness of the printing-color; therefore it is best to make test with one sheet. Then, if the metal does not adhere sufficiently, the pressure can be increased.
In the end all surplus gold or silver is removed by gentle wiping with clean cotton. This is easy, as it will have fastened itself only to the printed parts. If the impressions can be set aside for some days without being wiped, it is better, and there is not so much danger of injuring the brilliancy of the metal.
If gold and silver are to be printed on designs where there is other color also, or where there is black, the print on which the metal is to be applied must always be made first. Only when the sheets have been gilded or silvered, pressed, wiped, and cleaned, is the black design to be printed on from the next plate. That all this must be done with the register marks previously described is, of course, self-evident.
So I close my description of the Relief method; and I hope that I have made it all so clear that good results will come to all who follow my directions.
[CHAPTER II]
INTAGLIO METHOD
This differs from the other in that the fat, which is to attract the printing-color, is under the surface of the stone, the design having been either engraved-in or etched, and then filled with fat.
Like the preceding method, it has several branches. The best are these:—
I
THE LINE ENGRAVED STYLE
This is one of the most useful branches of lithography, and if the artist has attained enough skill and the printer knows his trade, it approaches very near to the handsomest copper plates, and at the same time is about three times easier and quicker than work on copper. It is splendidly adapted for writings and charts.
Choose a hard, uniform stone of the best kind. Grind it as finely as possible. Etch with aquafortis and prepare with gum. This, at least, was my early method, and it has remained in use in all printeries. Later, however, I discovered that it is almost better to coat the stone with gum without previous etching, because it can be more easily worked then. Only in that case it must be perfectly clean and contain no concealed fattiness. Immediately after the stone has been coated with gum (not some hours later, as many do) the gum must be removed with water, that it may not penetrate too deeply and thus cause a condition which will prevent the finest lines from taking on color subsequently.
Then coat the plate with a tint made of gum solution and lampblack or red chalk. Use a soft brush to make the coating very thin and uniform. It has the double purpose, first, of giving the stone a color so that the engraver can see his work, and of covering the prepared surface of the stone with a protective coat that later will admit the fatty printing-color only where it has been pierced by the engraving-tool. It is evident that this latter property is increased according to the amount of gum in it, yet only little gum must be used in it, the permissible amount being only just enough to insure that the coating shall not be easily wiped away during the work of engraving.
The stone must be absolutely dry before any work is done on it. Then the design is traced on it, or drafted directly on it with lead. Transfer by printing from paper is not advisable, because the resulting fattiness of the design makes the graver slip.
For the actual work of engraving there is no counsel to be given except to choose good and sharp needles of the very best steel, hard enough to cut glass; and that all lines must be graved clean. There must be no excessive pressure, and in wide strokes there must be no excessive depths. In making very fine lines the stone should merely be touched by the tool. If they appear white, and a little fine dust is observed, one may be certain that they will appear properly in the printing. Broad lines often can be made with one stroke of a flat needle, but generally they are made by continued, gradual scraping. If the stone is to be only lightly wiped during printing, the broad lines must not be deeper than strictly necessary to make them clear, as otherwise they will squash. In true art works, however, which are to be printed with firm color and under more powerful rubbing and wiping, the depths of all lines must be considered carefully, as they will print darker or lighter according to depth.
Of all things the worker must take heed against touching the stone with dirty or greasy hands, for a plate thus blemished is not only difficult to engrave, but the grease finally may penetrate through the slightly gummed coating and enter the stone, making much consequent trouble when the printing begins.
It is more harmful still to wet the stone in any way, because then the coating gum will dissolve, penetrate into the engraved lines and give them a preparation, so that they cannot take color afterward. Therefore, especially in winter, a very cold stone must be warmed before working on it with the design, as otherwise the moisture in the room will precipitate itself on the stone. Even the perspiration of the hands or the moisture of the breath may cause damage. Therefore a good but careful warming is very advisable.
If a plate has become moistened, as, for instance, from a breath, it must be permitted to dry before doing any further work on it, and especially it must not be wiped.
The dust resulting from the engraving is to be removed either with a soft brush or by blowing it away.
Faulty lines that are noticed during the engraving may be scraped flat very carefully so that no furrows are made, or they may be rubbed off with fine pumice, after which those places must be prepared again, and coated with gum applied with a small brush. Then the corrections can be made. If only tiny places are faulty, they need merely be coated with a mixture of weak phosphoric acid, gum, and lampblack or red chalk. This prepares them. Thus they will not take color during the print, and so are practically removed.
When the design is finished, the stone must be very dry that it may take color well. But it must not be warmed, as this would incline it to take smut. A color consisting of thin varnish, a little tallow, and lampblack is now rubbed swiftly into all the depressions, and immediately wiped away again with a woolen rag wetted with gum solution. This removes the original red or black coating also.
Thus the hitherto colored stone becomes perfectly white, while the engraved design, which has appeared white, is now black. The first impression that the eye will gain will be that now the design appears much finer than it did before. That is because every white line on a dark background looks wider than a black line of the same thickness on a white background. Therefore, while engraving, the artist should aim to make his lines a trifle bigger than his eye would suggest.
In printing the stone the usual precautions required in every form of lithographic printing must be observed. Beyond that, the matter of chief importance is the proper composition of the printing-color.
Stone plates made in this way can be inked-in (1) by rubbing-in the color and light wiping, and (2) by harder wiping, and (3) by the ink-roller.
For the first method, a color can be made of thin varnish and burned lampblack, the latter being present in fairly large quantity but very finely rubbed-down. Into this color is mixed a quantity, equivalent to one half the mass, of gum solution that is almost as thick as the color itself. Everything must be mixed perfectly. If the solution is too watery, it is not easy to mix it.
Three clean rags of cotton or linen are needed for inking. The first is used to wet the stone and to clean it again in the end. The second is colored with a small quantity of printing-color and rubbed in by thorough wiping to and fro. The third rag is used to clean away any surplus that may adhere. Then the first clean rag is used to cleanse the stone thoroughly.
All three rags must be wetted with gum solution, and the first and third must be washed several times during the day.
The stone plate is harder to clean at first than after some fifty impressions have been made. Often there will remain little specks of color on the prepared places, which are easy enough to wipe away but are inclined to reappear. To remedy this it may be necessary to use more clean rags in the beginning or more gum solution. If the stone has been polished very well in grinding, this trouble will not be very noticeable if at all. Under any circumstances, it will disappear gradually during the printing, so that at last it will be possible to clean the surface with the very same rag that lays the color on and is permeated with ink.
In the second method, the wiping is harder in order to take more color away from the shallower lines, so that they will be pale compared with the deep ones which then will appear very black and strong.
If the full beauty of a well-made copper plate is to be equaled, care must be taken, as said before, to achieve the proper depth of engraving, and the stone must be wiped harder. Otherwise the method is the same, except that beautiful, shining impressions often can be made by using a firm color, if the stone can bear the necessary tension.
The inking-in with the ink-roller is like the same process in other methods, except that the color must be softer and the roller well filled with it. It is necessary, also, to learn by practice how to work the color into all the deep lines.
The impression must be made immediately after inking, as otherwise the color will sink too deeply into the stone and not give a strong impression without renewed inking.
The paper must be wetted a little more than in the other method.
The tension of the press is according to the size of the plates, but on the whole must be two or three times greater than for the other methods. More pressure still may be needed for very fine work, as the finer lines often are harder to print than the coarse ones.
As soon as the first clean proof is pulled, it must be examined for errors or faults in the design. If there are any, the stone is removed from the press after being delicately coated with gum, and the correction is made as follows: Before anything else, all such faults as are to be removed entirely are either scraped away with a very sharp knife or rubbed away with a very fine stone. The manipulation must be very delicate to avoid grooves and furrows or sharp edges that afterward will hold dirt. Then the parts thus corrected are coated with a mixture of about six parts water, two parts gum, and one part aquafortis to prepare them anew.
If anything new is to be added to the design or drawn in place of an error, the stone is washed with water throughout, or, if the correction is to be made only in a very small part, washed at the desired place. Then it is coated with the red chalk as described in the beginning, but so thinly that the design can be seen plainly through the red coat. Now all that is desired can be engraved, filled again with the rubbing-in color, and turned over to the printer, who cleanses it with gum water and proceeds to print.
Only a few more useful suggestions:—
(1) It happens often that after the first rubbing-in of fat color and the succeeding cleansing with water, the stone gets a "tone" over its whole surface; that is, it takes color at least partly, and thus seems to have lost its original preparation. This may be due to the fact that not enough gum has been used in the original coating, or that the rubbing-in was rough enough to injure the protective coating, or that the rubbing-in-color was left on too long before being washed away with gum solution.
A similar fault may develop with the second rubbing-in, after corrections, and from the following causes: Poor color containing sand; too much pressure with the greasy rags; the use of rags not sufficiently cleansed of any soap used in washing them; rubbing-in of color with too dry a color rag; in brief, from anything that may destroy the stone's preparation wholly or in part.
Sometimes this defect may be remedied by mixing more gum into the printing-color and into the water with which the cleaning-rags are wetted. A firmer color may aid, if it is rubbed away by fairly strong pressure of the rag as soon as it has adhered. This operates as a remedy because the firm color takes hold of the dirt that has set itself into the pores of the stones, and when it is removed, takes the dirt with it. If none of these have results, there is nothing left except to grind off the plate very slightly and carefully with an exceedingly fine stone and gum solution. In the case of very delicate designs, this is not applicable, because the finest lines have practically no depth. Therefore they must be washed instead, a rag being dipped into weak aquafortis or very much diluted phosphoric acid, and passed carefully over the stone till the dirt disappears. It is well to mix in a little gum, and also to rub acid-proof ink into the stone first, that the etching fluid may not attack the design too much.
After this cleansing the tone will disappear, but another fault often appears in place of it. The color, after rubbing-in, will not permit itself to be wiped away readily, because the etching has caused some roughnesses to which the color adheres in the form of little specks. A number of clean rags with gum solution must then be used, or the stone should be lightly rolled a few times with the ink-roller after being rubbed-in. The roller will take the specks. Indeed, the fault hardly ever appears if the inking-in is done with the roller, as suggested in the remarks about the third form of inking-in.
As soon as some few impressions have been made, the roughness of the plate disappears gradually and it can be wiped off without leaving specks behind. Gentle rubbing with pumice finely powdered and mixed with gum solution will remove the defect in the very beginning, but care is needed lest the design be injured.
(2) A line that has so little depth that it is almost level with the surface of the stone can be made as black as a deeply engraved one by continued rubbing with the color rag. In using a firmer color the lines, especially the wider ones, can be so overloaded after a while that the ink will squash under the press. This surplus can be removed again by the use of the ink-roller, but it is merely adding unnecessary work, as proper practice in inking-in and the use of exactly the right consistency of color will prevent the trouble.
(3) The best way to ink-in an intaglio design is to rub it in at first with a somewhat firm color that however, contains enough gum, then to wipe it a bit, and after that to rub gently to and fro over the stone under gentle pressure, with a rag containing a less heavy color. A firmer color does not adhere well to the more delicate lines, or, at least, is hard to print; but by applying it first, the printing of the wider and deeper lines is facilitated, while the succeeding rubbing with softer color brings out the perfection of the finer lines.
The second rag with the lighter color must not be filled with it in mass, but should merely be made sooty with it, so to speak. Otherwise the lighter color would penetrate the deeper lines also and mix there with the heavier color.
In the end the stone must be wiped again with an entirely clean rag, as will be understood, of course, and thoroughly cleansed of all the color.
II
THE ETCHED METHOD
In this the design is not engraved into the stone by pressure of the hand, but with aquafortis or other acid, and only so much pressure is exerted in making the design as is required to cut through the thin coating of varnish with which the stone is covered. Therefore this method permits great freedom of action and is applicable especially for landscape work and for drawings in Rembrandt's style. In treatment as in effect it resembles copper plate, and has its own advantage in that the lines may be strengthened gradually by stronger pressure on the engraving-needle. They may even be engraved a little into the stone so that afterward the lines will become stronger under etching. This cannot be done with copper at all or only with great difficulty.
These considerations and the quicker printing permitted by it recommend the method to artists. In other respects it is not different from working on copper. But it is necessary that a good lithographer should be a master of this form of stone work, as it may be used for excellent work, not only by itself but in combination with the other methods.
The stone must be ground as smoothly as possible, then treated with aquafortis and coated with gum, so that its surface thus is completely prepared. The aquafortis may be as strong as that used for etching pen work. It suffices, also, to wipe the plate merely with a sponge dipped in stronger aquafortis, the chief point being that no roughnesses shall be caused by uneven etching.
A few minutes after this first operation is finished, the stone is rinsed with water, dried and coated with etching-ground. This can be best done as follows:—
(1) Warm the stone till an ordinary copper etcher's etching-ground will become so fluid on it that it can be worked with a leather ball like a varnish, and can be spread very thin and very evenly. Great care must be exercised lest uneven warming crack the stone. If one can put it into a nearby baker's oven, it will obviate the necessity for an especial apparatus, which otherwise is demanded.
After coating the stone with the etching-ground, it is reversed while still warm, and blackened by applying the flame of a tallow or wax candle, as the copper-plate etchers do with their plates. Then the stone is set aside to cool, with great precautions against dust. After it is cool, dust will not harm it, and it can be kept indefinitely before use, so long as the coating is protected against injury.
(2) The method given is the best; but if the warming of the stone is difficult, there is a method applicable to cold stones. The etching-ground is dissolved in oil of turpentine and laid on the stone with a clean ball. A stone so treated must be put away for at least a day in a place safe from dust that the oil of turpentine may evaporate.
To tint this etching-ground, it may be blackened by smoking with a candle, as in the first case; or color, such as lampblack or vermilion, may be mixed-in before it is applied. If one wishes to be very certain that the stone will bear the etching well, it may be coated, very thinly indeed, with a solution of very firm chemical ink after applying the etching-ground.
The design is traced through this coating to the stone. It may be transferred, also, but in that case, as soon as the transfer is on the stone, it must be coated thinly once more with a solution of chemical ink that does not, however, contain any lampblack or other coloring-matter, but is transparent. This is necessary to fill out any little holes and other injuries that may have been caused by the pressure during transfer or by the inequalities in the transfer paper.
The designing with the needle is done as in the engraved manner, except that the design is merely cut into the coating.
When the design is complete, the stone is laid into the etching-trough and diluted aquafortis, muriatic acid, or strong wine vinegar is poured over it repeatedly, according to the depth that the lines are to have.
If it is desired to etch so as to produce various tones,—some strong and some delicate,—after the manner of the copper-plate etchers, the pouring of acid should cease as soon as the very finest lines of the design have been etched sufficiently. Wash away every bit of acid with clean water and let it dry. Then, with a small brush and chemical ink, coat all parts that are not to be etched further. It is well if the chemical ink used for this purpose contains a little more soap than usual, so that it can penetrate well into all the depressions and leave no little holes. The coating must be done very cautiously, and it is better to paint on too much ink rather than too little, as the design will appear very dirty if etching fluid should penetrate here or there through the coated portions.
When the ink is dry, etching is resumed till the second tones have been etched as far as desired. Then the procedure is repeated, these second tones being coated. Thus one continues till all gradations of shading have been reached.
When the stone is fully etched, clean water is poured over it, and then all the parts that have not been coated with chemical ink are treated to a covering. The object of the previous coatings was to prevent access of acid to the parts; but at the same time the ink prepared the parts. Therefore the remaining portions of the design also must be sated with ink before the stone is inked-in for printing.
Let the stone dry and then pour on it as much oil of turpentine as may be necessary to dissolve this whole ground coating, which then is wiped off with a woolen rag wet with gum solution. Then the stone maybe inked-in and printed.
If an error is observed before etching begins, the first question is if the defect is deeply engraved in the stone or if it has been drawn merely through the ground coating without affecting the stone itself materially. In the latter case it is necessary merely to cover the defective place with chemical ink and draw into it the correction. If the error has been graved deeply into the stone, it must be covered for the time being, but nothing new can be drawn there. To do this, one must wait till the plate has been etched and rubbed-in with color. Then the incorrect part is scraped or ground off as evenly as possible, the place prepared anew with aquafortis and gum, and the correction made with the steel needle.
An intaglio design often is greatly beautified by being printed with a tint plate like a crayon design. It can be done with a second stone, but it can be obtained also with the one plate that has the design on it. Wash the designed stone with clean water and then paint a thick coat of chemical ink containing more soap than usual over the whole stone or over only such parts as one desires to improve by adding a tone. If lights are to be worked into this tone, it can be done, after inking-in, with a small brush dipped into weak aquafortis.
In printing a stone thus toned, it must be rubbed-in thoroughly with the black color and then cleaned as well as possible. The tint that shows on the surface then is usually too dark, and the firmer the color the darker it is. Then a second rag must be used with a much softer color, which may even be thinned-down with plain oil or butter. It may also contain another coloring substance. Rub this rag very gently to and fro without much pressure till it is apparent that the dark tone has been replaced by a light one. Then the stone is ready for printing.
Stones to be treated to a tint in this manner must be etched somewhat deeper than others, because the lines do not appear so dark against a tone.
In all intaglio methods there is the advantage that parts that turn out too dark can be modified by fine scraping or grinding. The stone merely must be rubbed with acid-proof ink beforehand, that the necessary preparation of the corrected places with aquafortis or phosphoric acid and gum may not attack the rest of the design. Those who attain skill in scraping or grinding with a small piece of black slate can make the softest gradations of shade in uniformly etched designs, and more easily and quickly than by drawing or coating and etching. If the stone has been rubbed-in with color for the first time only a short time previously, the ground or scraped surfaces do not even need to be etched. It is sufficient to wash them with a rag wetted in gum solution, because the color will not have penetrated the stone so deeply that it is likely to reappear.
III
DESIGN WITH PREPARING INK, COMBINED WITH SPATTERED AQUATINT
If a little dissolved gum is painted on a clean stone that then is inked over its whole surface with printing-ink, none will adhere where the gum is. In other words, the stone will have been prepared there. If the gum is permitted to dry before the ink is applied, those parts will become black, too; but as soon as a few drops of water are poured on and the ink-roller passes over the stone, all the gummed parts will show up white at once. This led me to make a color mixed with gum, with which one can design on stone and that would have the property of preparing it so that, on printing, the design or inscription will print white.
Some drops of gum arabic dissolved in water are mixed with an equal amount of lampblack and rubbed very fine. This makes an ink similar to Chinese ink, and keeps well when dried. It is rubbed down in a saucer with a little water and then is ready for use.
It can be used on a clean stone, but is likely to flow, for which reason the stone must be painted with a little weak aquafortis mixed with a little nutgall, and then well cleaned again. Still better is it to paint a clean stone some days before with oil of turpentine which is cleaned off again immediately. In that case, however, it is well to mix a little phosphoric acid into the drawing-ink, that the designed parts will be prepared the more surely.
When the design is dry, the whole stone is inked with printing-color, care being taken that not a drop of water touches it before it is perfectly black. Then a little water is poured on, after which there must be a little more rolling with the ink-roller till all the design that is drawn with the preparing-ink is very white and clean. Now the stone can be used for printing, being used in the manner used for pen work. To make the design more durable, that it may not in time thicken in its finer parts, the stone may be well inked-in with acid-proof ink and after a few hours, during which it draws together well, the drawing is etched in intaglio with aquafortis. Then it is coated with gum and the printing is not likely to damage the design.
Here we have an intaglio design which is prepared and prints white.
The case may be reversed, and the black plate may be made white again while the design will print black. This is because a stone treated with preparing-ink gives almost the same result, once it is grounded with acid-proof ink and etched as if the design had been engraved into etching-ground. The etched lines need simply be filled with chemical ink as in engraved work, to make them take color instead of coating them with gum. Then there remains only the obstacle that the stone is not prepared over its whole surface and takes color everywhere. However, it is not difficult to clean the plate and prepare it perfectly, especially if the stone is finely polished. It must be rubbed well with color, and wiped clean at once without rubbing too much of it away from the etched design. To make the color easier to wipe out, Frankfurter black and tallow may be mixed in it. Then the rag that has been used for inking-in is dipped into a mixture of twenty parts water, two parts gum, and one part aquafortis, or better still, phosphoric acid, and rubbed back and forth. The rag must not be too dirty and heavy with color, but it must contain some so that the delicate parts of the design shall not be wiped out and thus rendered susceptible to the acid. The next thing is to try with the finger to see whether the color on top can be easily rubbed away or not. In the latter case the wiping must be repeated till the cleansing mixture has so far prepared the surface that the wet hand or a wet piece of leather can cleanse it perfectly and free it from the dark tone. Now the stone is inked-in with firmer color (acid-proof ink is best). This is wiped off again thoroughly. Very weak aquafortis (or phosphoric acid if it has been used for the work) is then poured over it a few times, and this generally prepares it so well that it can be inked and cleaned easily during the printing.
This method is useful for many kinds of art, and it must not be imagined that it is superfluous because the other ways are quicker.
The engraving-needle is very good for drawing the finer parts of the design through the etching-ground, but the coarser ones cause much trouble, while with the pen, these are the very ones that are easiest to produce. By using this method, both advantages can be combined and only that is drawn with the pen which is most readily produced that way.
Thus the whole design, with the exception of the finest parts, is drawn on the white plate with the black preparing ink touche. Then, when it has been covered with acid-proof ink and made white, the finer parts are worked-in with the needle. Or they may be left till the end, when they are engraved-in.
For grounding or blackening the plate, one may use a substitute for the acid-proof ink if the ground is to be firmer. Use the etching-ground (mentioned several times before) of wax, mastic, pitch, and resin, dissolved in oil of turpentine and mixed with fine lampblack. It will then be susceptible of being laid beautifully uniform on the stone with the ink-roller like printing-ink.
The spattered aquatint method resembles this.
The outlines of the design are engraved or etched into the stone very delicately. After rubbing-in with black printing-ink and cleaning again thoroughly, it is rinsed with a great deal of clean water to take away every trace of gum. When it is dry a small brush is dipped into the preparing-ink, and the stone is spattered as described in the article on spatter-work. After drying, the dots that are too large are treated with the needle, and missing ones are drawn in with the pen. Now apply the roller with the dissolved etching-ground, that must, however, have only enough color so that the outlines of the design can show through it. Then the spattered work is brought out by rolling with water. Now coat the lighter parts of the design and etch. Coat again and etch again, in short do as already described for the method of successive etching till the required gradations of shade have been attained. Then proceed as usual with the inking-in and printing.
IV
AQUATINT IN COPPER-PLATE STYLES AND WITH ETCHING-GROUND
Any one who has the necessary appliances of the copper-plate worker for making the aquatint ground used by them, and who has the necessary skill, can do so, although the stone is endangered by the heat, and the process is not advisable. The stone is dusted with fine resin. A flame of spirits is applied below until the stone is so hot that the resin melts and forms the ground.
Better is that copper-plate method in which the resin is dissolved in highly rectified spirits of wine and poured quickly over the whole stone. By breathing on this, the resin is made to separate from the spirits and form tiny pellets, which thus make the required aquatint ground.
Both methods are better for very coarse work than for fine designs. Etching-ground, dissolved in oil of turpentine, or consisting simply of tallow and put on the stone very uniformly with a cotton ball, is much better, and produces an effect similar to wash drawing. However, it is better suited to the lighter parts of a design, because it will bear long and powerful etching only if one hits exactly the proper proportions between ground and etching fluid. Therefore, it is well, after the first tones have been etched and printed, to spatter cautiously with chemical ink all those parts that are to be darker than half-tones. Thus these dots will prepare the design so well at those places that they can withstand the most powerful etching.
V
AQUATINT THROUGH CRAYON GROUND
This is a sort of middle process between aquatint and the scraped style. It has the advantage of great speediness.
A stone that has been grained for crayon work is coated with the black or red gum ground described for the engraved method, but without previous etching, which would not do harm but is unnecessary. The outlines are drawn in with the needle very lightly, because they are to serve only to make the design visible. Those lines, however, that are not to disappear in the aquatint tone, but are to show plainly, must be cut as deeply as necessary for greater or lesser blackness. Then the stone is rubbed with color and washed with water as in the engraved method.
When it is entirely clean and dry, all the design will be black and the stone white. The design must be examined carefully, and the various gradations of shading should be separated in the mind into about eight leading classes, of which four are numbered upwards to the lightest parts, and four numbered downwards to the darkest. Everything in the category of the four dark parts now is worked strongly with chemical crayon. The purpose is to mass a number of evenly separated points over these parts of the design that shall withstand the etching fluid like an aquatint ground, between which the etching fluid may eat the stone and thus form a coarser grain than could be attained merely by rough grinding.
Then the four lighter parts must be coated with chemical ink. The very lightest parts, and all that is to remain white, must be left white on the plate and neither touched with crayon or ink.
Then the stone is etched for the first time. Following this pour clean water over it and let it dry. Then of the four dark parts the lightest are coated with chemical ink, and when it is dry the etching fluid is applied again. After washing and drying, the next lighter portions of the dark sections are coated, and so on till at last the very darkest shadows have been coated. Then a clean brush is dipped into gum solution and everything that should remain white is painted.
If a little oil of turpentine is now poured on the stone, and the crayon and chemical ink are dissolved and wiped off, the stone can be inked with soft inking-color and wiped again with a woolen rag. Then the design will look as if a black veil were over it, because the lightest parts of it and the half-shadows are not worked out at all. Wet a rag with gum solution and a little phosphoric acid, and hold it in one hand while with a fine scraper you scrape in the lights according to their gradation or grind them in with a fine stone, for instance, a slate pencil. As you scrape wipe over the design with the wet rag; and you will see exactly what you are doing as the various gradations will appear bit by bit. The printing in this as in other aquatint methods is done with soft and thin printing-color, and the paper may be more dampened than in other forms of lithography. The press needs considerable tension and the stones must be thick.
VI
INTAGLIO CRAYON AND TRACED DESIGNS
The difficulty of getting impressions from crayon that shall not differ from the original design on the stone led me to consider the use of the grained style of the copper-plate engravers. A crayon-like design in intaglio would have a greater strength in the dark parts and greater delicacy in the lighter; be more durable and more easily corrected. I saw at once that if I could attain some perfection, it would mean a great step forward in color printing, also. Thus there were originated the following two processes, which no doubt will in time interest artists to a high degree.
A stone grained for crayon work is prepared with aquafortis and gum. Then it is cleansed with water and covered with etching-ground when dry, as is prescribed for the etched process. The ground must be laid on so thinly and evenly that the design can be put in easily and that it still will resist the etching.
When the stone is cold and the outlines of the design have been traced on it, a scraper of the best steel is used to scrape in the lights and shadows. The scraper touches only the most elevated points of the grained surface at first, and produces larger points only after continued work, just as chemical crayon does. When the whole stone is finished, it is etched as in the etched process and then cleansed and printed in the same way.
If the stone is etched a little more strongly in all its gradations, it can afterward be ground down gently with very soft pumice, or, better still, with black slate and a gum solution, once it has been rubbed-in with color. This destroys all roughnesses that may remain from the first manipulations. Parts that have turned out too dark can be lightened by this polishing, and the over-light ones can be improved with the needle.
The designs made in this manner possess more delicacy as well as more strength than the ordinary crayon designs, and there remains to be desired only that they might have the advantage of the latter of being worked black on white, as it is so much easier for the artist to judge his work on the stone.
Of trials made in this direction, the two following ones met my views the best.
One way is to grind the stone rough, pour diluted aquafortis and nutgall over it, clean it with water and dry it. Then the design is drawn on it with a black chalk made of oil of vitriol, tartar, and lampblack. The further treatment is the same as that in the case of designs done with preparing-ink.
I have not been able to give enough time to this process to invent a preparing-crayon that shall be very hard without losing its preparing-property. However, the compound mentioned will produce a crayon with which one can work well after a few days. It has the advantage that it may be rubbed on a shading-stump made of rolled paper, which will prove excellent for working the finest shadings into the plate.
The other way is as follows: A colorless chemical ink is made of one part wax, two parts tallow, and one part soap. This I dissolved in water and with it I coated the stone, which had been ground rough and prepared with phosphoric acid, nutgall, and gum, and then washed with water. The coating was applied very lightly, but enough so that it could bear the succeeding etching.
As soon as it was dry, I drew the design on it with a black crayon made of tartar, gum, a little sugar, and a good amount of lampblack, or I used the ordinary black Paris crayon or a fine English lead pencil. Then the design was etched, after which alum water was poured over it, and it was set aside to dry.
As soon as it was absolutely dry, I coated it with fatty color, and then cleaned the stone with oil of turpentine and gum solution. If I wanted an exceedingly smooth surface, I ground the stone gently; but then the design had to be etched deeply.
The good results of these two experiments led me to the following process: By following my instructions exactly the worker can produce striking imitations of wash as well as crayon drawings, and at the same time unite the greatest possible ease of drawing as well as certainty of good impressions, so that this process really deserves to be called one of the very best of all printing-methods.
The outlines of the drawing must be drawn on the finest and thinnest paper that can be obtained. Then a very finely polished stone is prepared with aquafortis and gum, or, better still, with phosphoric acid, nutgall, and gum, cleansed with water and dried. Then it is coated very thinly with tallow, which is patted with a very clean leather ball or with the hand, so that it shall be very uniformly laid over the stone. Everything depends on the thinness and uniformity of this tallow coating. Then the stone must be smoked with a wax torch or a tallow candle. The durability of the ground depends on this smoking, as without it a very thin coating of tallow would be penetrated by the acid.
Now the stone is ready for the design. It must not be touched by so much as a finger. The designed paper is pasted to the stone at the ends, without pulling, as the least motion would injure the stone's surface. The arrangement of elevated supports for the hand (previously described) is needed for the succeeding work. The drawing is then done on the paper with Paris chalk, delicate Spanish chalk, an English lead pencil, or with a small piece of lead. All that is drawn on the paper will impress itself on the stone underneath and remove the ground at those places, thus opening the surface for etching.
When the drawing is finished, it is etched and covered as with the etched process, and afterward is printed as in that process.
When sufficient practice has made one a master of this style, it will be amazing what great perfection, what miniature-like delicacy, and also what strength can be obtained by proper etching.
Besides, this latter process is applicable in combination with the etched process.
VII
TOUCHE DRAWING WITH ETCHING INK
This method is very useful for filling-out etched or engraved designs, also for correcting and completing the various aquatint processes.
Dip a little brush into lemon juice mixed with a little lampblack and draw the design on the finely polished and prepared stone. The acid will eat little holes into it, which will take color if the lemon juice is washed away as soon as it has completed its etching, and the etched part has been dried and rubbed-in with fat color. To produce darker shadings it can be laid on the same place twice, and for lighter shadings the acid either is washed away sooner or diluted with water.
I do not doubt that a skillful chemist could invent an etching ink which would be even more perfect, and then a drawing could be washed on the stone as easily as on paper, which would mean immense advance for the art.
[CHAPTER III]
MIXED METHODS
Stone-printing has the unique property, owned by no other process, that it is possible to print relief and intaglio simultaneously. This property makes possible so many combinations of the two processes that a book might be filled with their description. I assume, however, that the reader will have understood the entire science of the new art from what I have said, and that his own reflection will tell him what methods to use or to combine for each of his purposes. I limit myself, therefore, to a few leading methods, thus giving some fundamental idea of the manipulations.
I
PEN DESIGN COMBINED WITH ENGRAVING
This can be utilized in two ways:—
When the pen drawing is finished and etched, the stone may be coated with red gum covering and the needle used to draw-in the finest lines. The printing is the same as with pen work. The second way is to make the engraved or etched part of the design first, and after the stone has been rubbed-in with acid-proof ink, cleansed and dried, to draw-in the rest with the pen and chemical ink. As soon as the design is properly dried, it is etched a little and prepared, and otherwise handled like an ordinary pen drawing.
Both ways carry the advantage that the pen can be used for those parts best done with the pen, and the engraving-tool for those parts best done with it. The latter is especially excellent for very fine and elegant script, such as title-pages, the finest strokes being made first with the needle and the broader ones with the pen.
II
INTAGLIO DESIGN WITH RELIEF TINT
This has been described thoroughly in our chapter on etched work.
III
INTAGLIO AND RELIEF WITH SEVERAL PLATES
As already shown, intaglio and relief can be printed on one stone. Therefore it is evident that the two methods can be utilized still better for several plates, for instance, printing on an etched design with one or more plates that are tinted in relief, or by printing over a crayon or pen design in relief a tone plate in aquatint in intaglio.
How to do this has been explained in the descriptions of relief and intaglio methods.
IV
TRANSFORMING RELIEF INTO INTAGLIO AND VICE VERSA
This is, so to speak, the test of a good lithographer, as it is the most difficult of all methods, and demands exact knowledge of all manipulations. I will try to explain it with a few examples.
EXAMPLE I
To etch a transfer into intaglio
Prepare a finely ground plate with phosphoric acid and gum, wash very well with water, and let it dry. Now transfer to it a design made with soft ink or crayon, or a fresh copper-plate impression. Let the stone rest for a few hours, that the fatty colors may take hold well. Coat it with clean gum water, and with a rag dipped into acid-proof ink try to rub about as much color on the design as appears to be required to make it withstand some etching. This etching is done with pure aquafortis which in addition has a little alum mixed with it. Etch only enough to eat away the uppermost parts of the prepared surface that have not been permeated with fat. Pour clean water over the whole stone and coat it with strong soap-water that is permitted to dry on it. Finally, clean away the soap with oil of turpentine. Ink-in with acid-proof color which will color the whole stone. Now as soon as it is wiped gently with a rag dipped in gum solution and weak phosphoric acid, the whole design will appear in white as if it had been made with preparing-ink. If the stone is inked now with acid-proof ink and treated exactly as instructed in the article on the use of preparing-ink, the design that was in relief originally will be found in intaglio.
This process is capable of great perfection and can produce true masterpieces especially if the stone is treated finally with the engraving tool.
EXAMPLE II
To etch into intaglio a design made with chemical fatty ink or crayon
Etch and prepare the clean stone with phosphoric acid and gum. Then put on the design with ink or crayon, and perform the succeeding etching and other manipulations exactly as in the preceding case.
EXAMPLE III
To etch into intaglio any design etched into relief
In the two examples given, the plate is etched with phosphoric acid before transfers or designs are made on it. As the weak etching with aquafortis and alum does not penetrate the places where there is fat, these retain their phosphorus-preparation, and thus are not so readily destroyed by the succeeding application of soap, whereas the etched parts immediately drink in the fat as soon as the soap touches them.
In stones designed in the ordinary way, where the design does not lie on the prepared surface, but has really penetrated well into the stone, the transforming is somewhat more difficult, but can always be done after practice by using the following means:—
Wash the stone with water and then coat chemical ink or strong soap-water over it and let it dry. Then clean the stone with oil of turpentine and ink-in well with acid-proof color. Dip a linen rag into gum water and phosphoric acid and endeavor to wipe away the color from the relief design. After wiping to and fro quickly a few times, try with the finger if the design will not whiten, or if the wiping with the acid must be continued. Care must be taken not to injure the ground through too much pressure. When the design gets pretty white, ink the stone with firm acid-proof ink, and then treat as in the preceding cases.
In this way designs in relief that have not turned out as desired can be changed into intaglio, and then, by the use of successive coatings and etchings, as described before, improved by making gradations of tones. But it requires great skill, lacking which one may destroy his plates utterly.
EXAMPLE IV
To change an intaglio design into relief for easier printing
Many kinds of scripts and designs are easier to engrave with a needle than to do in relief with a pen; or one may have workmen who can use the engraving tool better than the pen, as the use of the latter requires more industry and skill than the use of the etching- or engraving-needle.
If one wishes to transform such a design into one in relief, because then it can be printed more quickly and easily and also will give more impressions, the following method will prove useful:—
Ink the stone with good acid-proof ink, and after a few hours etch it like a pen design till it is apparent that the design is showing up. Let it rest again a few hours after etching and become quite dry. Then coat with gum. Otherwise treat it for printing like an ordinary pen design.
Now I believe that I have described faithfully and as clearly as I can all the lithographic methods to which unceasing research and endless experimentation have led me. In the following Appendix I merely make a few useful remarks, which do not pertain exclusively to lithography, yet are intimately connected with it and surely will not be unwelcome to art lovers.
[APPENDIX]
I
PRINTING WITH WATER AND OIL COLORS SIMULTANEOUSLY
When a plate, whether intaglio or relief, has been inked-in with oil color, it may be coated with one water color, or it may be illuminated with several, and then printed-off in one impression. Two parts of gum and one part of sugar are used for this. They can be dissolved with any water color. Care need be taken merely that the colors are well dried before the impression is made.
If, however, it is desired that the colors have shades so that the impressions may resemble English or French colored copper-plate prints, the process is as follows:—
Etch all shades of the color pretty deeply in any of the stippled or aquatint styles. After this, coat the stone with gum solution, that it shall take no color in these depressions. Clean off the chemical ink or the ground with oil of turpentine, and prepare the whole plate if it has not been prepared already on its surface. Then coat it with red gum surface, and into this inscribe all those lines that are to remain black. Then the color is rubbed-in and the stone cleansed so that it will be white everywhere except in the engraved parts. When it is inked-in now, it can take color there only, and the other depressions (namely the various shades of the color) will remain white because they have been prepared. Now it is necessary only to coat each part with the desired water color and it will be denser, and therefore darker, wherever there are more and greater depressions.
II
SIMULTANEOUS CHEMICAL AND MECHANICAL PRINTING
When a pen drawing is so constituted that the various lines are close together and there is no white space on it that is greater than at most one half inch in diameter, it will permit printing in a purely mechanical way without being prepared. It need merely be etched into all the relief possible without under-eating the lines. All that is needed then is a color-board or a so-called dauber, made as follows:—
A thin board of soft wood, about eight inches long and six inches wide, is planed down till it is not more than one line in thickness. Glue on it a piece of fine cloth or felt almost as large as it. Over this glue another board, of the same area as the first, but one quarter inch thick. It must be very well-dried wood, and must be made very true with the plane, or better still, by rubbing on a perfectly level stone with sand. This latter board is provided with a handle; and when all is dry this dauber is ground off true again with fine sand and oil on a stone.
Lay the printing-color on this utensil very gently and uniformly with a leather ball. Tap and pat the stone, which has first been cleaned with oil of turpentine over its whole surface, very carefully with the appliance, holding it as horizontal as possible and taking great pains to distribute the color evenly.
As compared with chemical printing, this process in itself has no advantages, but can be united with it and thus used to print three colors from one plate. This is shown by the following
EXAMPLE
Suppose that a design shall be colored black, blue, and red, and that all these colors shall be put simultaneously on one plate. Take a stone made ready for pen work, and prepare it first of all with phosphoric acid, nutgall, and gum, then wash it with water, and let it dry. Now draw-in all that is to be red with chemical ink, that must, however, contain only just enough soap to permit its solution. When this drawing is dry, etch it into pretty high relief, the higher the better. After this prepare the stone with gum, wash it, and let it dry again. Then coat it with etching-ground that has been dissolved in oil of turpentine, and draw-in all that is to be black, between and over the high etched parts. Then etch this design pretty powerfully into intaglio, after which wash with water, rinse with alum solution, and dry. When the plate is thoroughly dry, rub-in printing-color, and clean with a woolen rag dipped into gum solution and oil of turpentine. Then it will become white everywhere except in the deep lines where it will have taken color. After cleansing again with water and drying, draw-in all parts that are to be blue, using a chemical ink that contains a great deal of soap. Let this dry well, and cleanse the plate with gum and oil of turpentine again. Then it is ready for inking-in.
To lay on the color, proceed as follows:—
First the black is rubbed-in, as prescribed in the article on the intaglio style. In the very deep parts the stone will get very black. In the parts last drawn, that are level with the surface, it will be only gray, if the color permits ready wiping, which can be facilitated by the use of gum and a woolen rag. Then the tone remaining on the level parts drawn with the chemical ink will be so pale that it will not affect the blue color. Now wipe a rag dipped in blue color gently to and fro till everything that is to be blue has taken the color well. Then take the dauber which has been filled with red color, and pat the stone, which should be dry by that time. Then the parts of the design in high relief will take the red color, and thus an impression can be made with the three colors at once. Each inking-in must be done the same way.
III
USE OF THE STONE FOR COTTON-PRINTING THROUGH WIPING. A UNIQUE PRINTING PROCESS
Etched copper plates have been used for some considerable time for cotton-printing, and as the ordinary oil colors were not suitable for this, while the suitable colors were too fluid, so that they were always wiped out of the engravings, another method was devised. The plate was covered with color and then a kind of straight edge was scraped across it, which removed all color from the surface, leaving it only in the depressions.
This same sort of wiping is applicable to stone, and it is necessary merely to see that the stone is very even and highly polished. The color must be one that permits itself to be wiped off clean, and the wiper must be very uniform and sharp.
Starch-paste or gum with some caustic material is easily scraped off.
IV
COLOR PRINT WITH WIPING
This process is also useful for printing papers such as cotton papers, tapestry, etc. Almost all intaglio designs permit good printing in this way, if a handsome color is used.
Fresh cheese, or drops of congealed milk, mixed with soap, potash, linseed oil varnish, and the desired tint, make an excellent composition, with which all intaglio designs, even aquatints, can be printed handsomely if the plate is very smooth.
If the design is made well, the various colors can be laid on quite roughly, care being taken merely that each color shall be laid only where it is desired. Then the stone should be permitted to dry, after which all the surplus colors can be scraped away with one manipulation, without danger that one will mix with the other in the design.
V
OIL-PAINTING PRINT THROUGH TRANSFER
Colored impressions resembling oil paintings can be made by printing with colors and several plates on paper grounded with oil color. But perfect oil paintings are produced only as follows:—
Make a considerable quantity of special paper by coating unsized paper thinly with starch-paste or glue. On this make the separate impressions from each color plate. If the painting itself is to be produced from these separate parts, take a canvas that has been prepared for oil painting and lay on it a wetted impression of one of the colors, let us say, red. Print this off under light tension of the press, and when the paper is pulled away, it will be seen that the color has been transferred to the canvas. Then a wet impression of another color is laid carefully in place so that it will register exactly, and the process is repeated, till all the colors have been transferred to the canvas.
The transferring can be done with the hand or with any other method, as no great power is needed, since the color transfers itself readily.
VI
STONE-PAPER
This is the name already generally adopted for a substitute invented by me for the Solenhofen stones.
I had been trying for a long time to invent some stone-like mixture that would be equally suitable for printing. The ordinary parchment of the writing-tablets would do if its surface were not soluble in water. I made considerable progress with a composition of lime and freshly congealed milk after the mixture had aged enough so that the lime could sate itself with oxygen. Then I made a composition of chalk, gypsum, and glue, which I dipped into a solution of nutgall and alum, and I was able to use this for coarser work, at least, if not too many impressions were required.
I did not get a wholly satisfactory idea, however, until I observed that fat spots that were caused on a stone by oil, and also designs that had been transferred to the stone with mere oil color, refused to take color after a few weeks if they were prepared in only the slightest degree.
I reasoned from this that oil suffered a change from exposure to air, and by combining itself presumably with oxygen acquired a more earthy character. This deduction may be correct or not; but it led me to experiment with oil as a binder for various earthy substances, because I reasoned that such a composition would be insoluble in water. The only question, then, would be if despite the intermixed oil it would permit itself to be prepared, that is, if it could be made resistant to other fats.
The result justified my hopes so thoroughly that I am convinced now that with various compositions of clay, chalk, linseed oil, and metallic oxides a stone-like mass can be made that is excellent for coating paper, linen, wood, metal, etc., and thus for making plates that not only replace the stone for printing, but in many cases are far superior to it.
I shall give the world a book soon about these fortunate attempts of mine, and thus perhaps give expert chemists an opportunity to perfect my invention still more.
VII
CHEMICAL PRINT ON METAL PLATES
All metals have great inclination for fats; but if they are quite clean, being ground with pumice, for instance, or rubbed-down with chalk, they can be prepared like a stone, that is, they acquire the property of resisting oil color, thus becoming available for chemical printing.
Iron and zinc can be prepared like the stone with aquafortis and gum.
To prepare zinc and lead, aquafortis with nutgall and gum will serve, but a slight admixture of blue vitriol will make still a better preparation, and this in a degree that improves according to the amount of copper that the surface acquires from the coating. The most durable preparation for lead and zinc is a mixture of aquafortis, gum, and nitrate of copper.
Brass and copper are best prepared with aquafortis, gum, and nitrate of lime, all mixed in proper proportions.
Lime and gum are a good preparation for all metals; also potash with salt and gum.
This alkaline preparation, however, is applicable only for the intaglio style. For the relief style, the acids are better.
Recently I have applied chemical printing from metal plates to a new form of copying-machines, with which everything written or drawn with chemical ink or crayon on paper can be transferred in a few moments and manifolded several hundred times. His Royal Majesty of Bavaria has had the supreme condescension to grant me a six years' patent on this invention.
Until now I have not been able to give this matter the necessary attention because the work of publishing this book hindered me; but now I shall make such a stock of these simple, convenient, and so widely useful hand-presses that it will be worth while to open a subscription, which would enable me to sell them for a low price. This would please me best, as my highest reward would be the general use of my inventions, to fulfill which desire I have taken the utmost pains in this work.
In the last parts of the book I have gone less into details, merely because I assume that those who have mastered the first parts of this work will not need many words to understand the rest.
If the demand for this perhaps prematurely announced book had not become so vehement lately that I could not possibly delay its publication any longer, I should have tried to produce sample illustrations that combine inner art value with good printing. As it is, I postpone this for a supplementary volume soon to appear, in which I shall occupy myself mainly with processes and methods not yet generally known, representing each by means of a true work of art. With which I now end my text-book, with the hearty wish that it will find many friends and create many good lithographers. This may God grant!
The Riverside Press
PRINTED BY H. O. HOUGHTON & CO.
CAMBRIDGE, MASS.
U.S.A.
Transcriber's Notes:
Punctuation and spelling standardized.
Inconsistent hyphenation retained.
This book had no overall Table of Contents; the one before the start of the book was created by the transcriber.