Water will answer for common purposes, but white wine formed a blacker ink than water, and vinegar formed one still blacker than wine. The addition of spirit injured the color, and occasioned a precipitation of coloring matter—a decoction of logwood, instead of water, improved both the beauty and deepness of the black. The ingredients are to be put in a glass or other convenient vessel, not metallic, and the mixture shaken four or five times a day. In ten or twelve days it will be fit for use, and sooner if in a warm situation; but it continues for a long time to improve if left without decantation. When it is separated from the powdery residue, it will be kept in a good state with greater certainty, if some broken galls freed from the powder and some pieces of iron are put into it. Iron, however, is the only metal which it is safe to retain in contact with the ink.
Dr. Lewis gave the preference to distilled or rain water in {306} the manufacture of ink, but it seems probable that a water containing a certain proportion of carbonate of lime is more suitable. In dyeing a black color by means of galls or sumach and copperas, hard spring water is preferred by some dyers. To produce in a liquid a given depth of color, distilled water requires more dyestuff than common spring water. This is illustrated in the following experiment, devised by Mr. Phillips: into two glass jars of the same size, each half-filled with distilled water, introduce equal quantities of infusion or tincture of galls or sumach, and an equal number of drops (only three or four) of a solution of copperas; a faint purplish color will be developed in both jars, but if one is filled with spring water, the color in that rapidly becomes dark reddish-black, and one-half more water is required to reduce it to the same shade of color as the other. The water which is found by experience to be best adapted for dyeing with galls and sulphate of iron, differs from distilled water in containing sulphate of lime, carbonate of lime held in solution by free carbonic acid, and chloride of calcium. The beneficial ingredient seems to be the carbonate of lime, which possesses slight alkaline properties, for if the smallest quantity of ammonia or of bicarbonate of potash is added to the distilled water in the above experiments, the purple color is struck as rapidly and as deeply as in the spring water; chloride of calcium and sulphate of lime, on the contrary, produce no sensible change either in the depth of color or the tint. The effect is no doubt referable to the action of the alkali or lime on the proto-sulphate of iron, by which the sulphuric acid of the latter is withdrawn, and hydrated protoxide of iron set free, for protoxide of iron is much more easily peroxidized and acted upon by tannic and gallic acids (the dyeing principles of galls) when in the free and hydrated state, than when in combination with sulphuric acid. Neither the caustic fixed alkalies (potash and soda) nor their carbonates can be well introduced in the above experiments, as the slightest excess reacts on the purple color, converting it into a reddish-brown. Ammonia, lime-water, and the alkaline {307} bicarbonates also produce a reddening, and if applied in considerable quantity a brownish tinge. It is very probable that the above-mentioned principle is applicable to the preparation of writing ink.
RIBANCOURT’S WRITING INK.—M. Ribancourt, who paid much attention to the preparation of inks, stated that none of the ingredients should be in excess. “If there be a want of the matter of galls, part of the vitriol will not be decomposed; if, on the contrary, there be too much, the vitriol will take as much as it can decompose, and the remainder will be nearly in the state of the decoction of galls, subject to change by becoming mouldy, or to undergo an alteration after writing which destroys its legibility much more completely than the change undergone by ink containing too small a portion of the galls.
“It is doubtful whether the principles of the galls are well extracted by cold maceration, and it is certain that inks made in this way flow pale from the pen, and are not of so deep a black as those wherein strong boiling is recurred to.”
From all the foregoing considertions, M. Ribancourt gives the following directions for the composition of good ink:—
“Take 8 oz. of Aleppo galls (in coarse powder); 4 oz. of logwood (in thin chips); 4 oz. of vitriol of iron; 3 oz. of gum arabic (in powder); 1 oz. of vitriol of copper; and 1 oz. of sugar-candy. Boil the galls and logwood together in 12 lb of water for one hour, or till half the liquid has evaporated. Strain the decoction through a hair sieve or linen cloth, and then add the other ingredients. Stir the mixture till the whole is dissolved (more especially the gum), after which leave it to subside for twenty-four hours. Then decant the ink, and preserve it in bottles of glass or stoneware well corked.” The sulphate of copper must be omitted in the preparation of an ink required for steel pens.
DR. BOSTOCK’S INSTRUCTIONS FOR THE MANUFACTURE OF INK.—A few years since, Dr. Bostock presented to the Society of Arts the following, valuable communication “On the Properties of Writing Inks,” which will be read with interest. {308}
“When the sulphate of iron and the infusion of galls are added together, for the purpose of forming ink, we may presume that the metallic salt or oxide enters into combination with at least four proximate vegetable principles, viz: gallic acid, tan, mucilage, and extractive matter, all of which appear to enter into the composition of the soluble part of the gall-nut. It has been generally supposed that two of these, the gallic acid and the tan, are more especially necessary to the constitution of ink; and hence it is considered, by our best systematic writers, to be essentially a tannogallate of iron. It has been also supposed that the peroxide of iron alone possesses the property of forming the black compound which constitutes ink, and that the substance of ink is rather mechanically suspended in the fluid than dissolved in it.
“Ink, as it is usually prepared, is disposed to undergo certain changes, which considerably impair its value; of these, the three following are the most important:—Its tendency to moulding; the liability of the black matter to separate from the fluid, the ink then becoming what is termed ropy; and loss of color, the black first changing to brown, and at length almost entirely disappearing.
“Besides these, there are objects of minor importance to be attended to in the formation of ink. Its consistence should be such as to enable it to flow easily from the pen, without, on the one hand, its being so liquid as to blur the paper, or on the other, so adhesive as to clog the pen and be long in drying. The shade of color is not to be disregarded; a black approaching to blue is more agreeable to the eye than browner ink; and a degree of lustre or glossiness, if compatible with due consistence of the fluid, tends to render the characters more legible and beautiful.