A Treatise on Etching

by Maxime Lalanne

3. Grounding the Plate.—Having procured all these requisites, the first thing to do will be to clean the plate so as to remove any oil or other impurities that may have been left on it by the plate-maker. Wash and rub it well on both sides with a soft cotton rag and benzine, and then rub with whiting, as you would do if you were to clean a door-plate. Take care to remove all the whiting with a clean rag. Now take hold of your plate by one of its corners with the hand-vice, wrench, or pincers, between the jaws of which you have put a bit of card-board or stout paper, so as not to mark the plate. Hold it over the stove, spirit lamp, or ignited alcohol, and see to it that it is heated evenly throughout. Hold the plate in your left hand while heating it, and with the other press against it the ball of ground wrapped up in silk. As soon as you see the ground melting through the silk, distribute it over the plate by rubbing the ball all over its surface (the polished surface, as a matter of course), taking care the while that the plate remains just hot enough to melt the ground. If it is too hot, the ground will commence to boil and will finally burn. The bubbles caused by boiling are liable to leave air-holes in the ground through which the acid may bite little holes in the plate; burning ruins the ground altogether, so that it loses its power of withstanding the acid. After you have distributed the ground tolerably evenly, and in a thin layer, lay the plate down on the table (keeping hold of it, however, by the corner), and finish the distribution of the ground by dabbing with the dabber. Strike the plate quickly and with some force at first, and treat it more gently as the ground begins to cool. If it should have cooled too much, before the distribution is accomplished to your satisfaction, in which case the dabber will draw threads, heat the plate gently. The dabber not only equalizes the distribution of the varnish, but also removes what is superfluous. An extremely thin layer of ground is sufficient.

4. Smoking the Plate.—While the plate is yet hot, and the ground soft, it must be smoked. Light your tapers or your oil torch, and turn the plate upside down. Allow the flame just to touch the plate, and keep moving it about rapidly, so that it may touch all points of the plate, without remaining long at any one of them. If this precaution is ignored, the ground will be burned, with the result before stated. The smoking is finished as soon as the plate is uniformly blackened all over, and the glimmer of the metal can no longer be seen through the ground. Now allow the plate to cool so that the ground may harden. Avoid dust as much as possible while grounding and smoking the plate. Particles of dust embedded in the ground may cause holes which will admit the acid where you do not wish it to act.

5. Points or Needles.—The plate is now ready for drawing upon it, but before you can proceed to draw you must prepare your points or needles. Two will do for this first experiment, a fine one and a coarse one. For the fine one you may use a sewing-needle, for the coarser one a medium embroidery needle, both set in wood so that the points project about a quarter of an inch. If you are going to use rat-tail files, grind the handle-ends on your oil-stone until they attain the requisite fineness. Hold the file flat on the stone, so as to get a gradually tapering point, and turn continually. See to it that even the point of your finest needle is not too sharp. If it scratches when you draw it lightly over a piece of card-board, describe circles with it on the board until it simply makes a mark without scratching. The coarse needle must be evenly rounded, as otherwise it may have a cutting point somewhere.

Pl. A.

6. Drawing on the Plate.—As the purpose of your experiment is simply to familiarize yourself with the technicalities of etching, that is to say, with the preparation of the plate, the management of the points, and the action of the acid, it will be well to confine yourself to the drawing of lines something like those on [Pl. A.] It is the office of the point simply to remove the ground, and lay bare the copper. But this it must do thoroughly, for the slightest covering left on the plate will prevent the acid from attacking the copper. You must therefore use sufficient pressure to accomplish this end, but at the same time you must avoid cutting into the copper by using too much pressure. Wherever the point has cut the copper the acid acts more rapidly, as the polished coating of the surface of the plate has been removed. It is evident from this that an even pressure is necessary to produce an evenly bitten line. Do not touch the ground with your hands while drawing. Rest your hand on three or four thicknesses of soft blotting-paper. When you desire to shift the paper, lift it, and never draw it over the ground. Hold the point, not slantingly like a pencil, but as near as possible perpendicularly. The point is a hard instrument, with which you cannot produce a swelling line, as with a pencil or a pen. Therefore your only aim must be an even line, produced by even pressure. The minute threads of ground thrown up by the point you must remove with your largest camel's-hair brush; otherwise they may clog your lines. Before commencing to draw read the description of Pl. A given under the heading “[Description of Plates].”

7. Preparing the Plate for the Bath.—If you were to put the plate into the acid bath in the state in which it is at present, the acid would corrode the unprotected parts. To prevent this paint the back, and the corner by which you held the plate while grounding it, and the edges with stopping-out varnish. If you are not in a hurry (and it is always best not to be in a hurry), let the varnish dry over night; if you cannot wait so long an hour will be sufficient for drying. While the plate is drying you may lay it, face downward, on a little pile of soft paper, made up of pieces smaller than the plate, so that the paper may not touch the varnished edges.

8. The Bath.—The preparation of the bath is next in order. Ascertain the capacity of the dish or tray you are going to use by pouring water into it to fill it to half its height, and then measuring the water. Pour one half of this quantity of water back into the tray, and add to it the same quantity of nitric acid, stirring the mixture well with a glass rod, or a bit of glass, or a bird's feather, if you happen to have one, or in default of all these with a bit of stick. The mixing of water and acid induces chemical action, and this produces heat. The bath must therefore be allowed to cool half an hour or so, before the plate is put into it. Nitric acid being a corrosive and poisonous fluid, it is well to use some care in handling it. Otherwise it may bite holes into your clothing, and disfigure your hands, as before noted. By the side of your bath have a large vessel filled with clean water, in which to wash the plate when it is withdrawn from the bath, and your fingers in case you should soil them with acid.

9. Biting and Stopping Out.—The bath having been prepared, and the varnish on the back and edges of the plate having dried sufficiently, lay the plate on the plate-lifter, face upward, and lift it into the bath. In a few minutes, in hot weather in a few seconds, the acid will begin to act on the copper. This is made evident to the eye by the bubbles which collect in the lines, and to the nose by the fumes of nitrous acid which the bath exhales. The bubbles must be removed by gently brushing them out of the lines with a brush or the vane of a feather; the fumes it is best not to inhale, as they irritate the throat. After the biting has gone on for three minutes in warm, or for five minutes in cold weather, lift the plate out of the bath into the vessel filled with water. Having washed it well, so as to remove all traces of the acid, lay it on a piece of blotting-paper, and take up the moisture from the face by gently pressing another piece of the same paper against it. Then fan the plate for some minutes to make sure that it is absolutely dry. If you have a pair of bellows you may dispense with the blotting-paper as well as with the fanning. The lines on the plate, having all bitten for the same length of time, are now all of about the same depth, and if the plate were cleaned and an impression taken from it, they would all appear of about the same strength, the only difference being that produced by difference in spacing and in the size of the needles. This is the point where the stopping-out varnish comes in. With a fine camel's-hair brush stop out, that is to say, paint over with stopping-out varnish, those lines or parts of lines which are to remain as they are. If the varnish should be too thick to flow easily from the brush, mix a small quantity of it in a paint saucer, or on a porcelain slab, or a piece of glass, with a few drops of benzine. The varnish, however, must not be too thin, as in that case it will run in the lines, and will fill them where you do not wish them to be filled. If it is of the right consistency, you can draw a clean and sharp line across the etched lines without danger of running. When you have laid on your stopping-out varnish, fan it for some minutes until it has dried sufficiently not to adhere to the finger when lightly touched. Then introduce the plate into the bath again, and let the biting continue another five minutes. Remove again, stop out as before, and continue these operations as often as you wish. But it would be useless to let your accumulated bitings on this experimental plate exceed more than thirty minutes. Having finished your last biting, clean the plate with benzine. Then apply the same process to your hands, and follow it up with a vigorous application of soap and nail-brush. This will leave your hands as beautiful as they were before.