Inks, are fluid compositions designed for writing, drawing, and printing As there are a great variety of sorts, we shall treat them consecutively, according to the following arrangement of the subject.
For Writing. 1. On black writing inks generally 2. On common black writing ink. 3. On best, or Japan ink. 4.. Copying ink. 5. Indelible, or indestructible ink. 6. Red ink. 7. Indestructible red ink. 8. Blue ink. 9. Yellow ink. 10. Green, and other coloured inks. 11. Cloth-marking ink. 12. Sympathetic, invisible, or secret inks. 13. Lithographic ink.
1. Black Writing Inks generally. - When any vegetable matter, containing the gallic acid, is infused with a solution of iron in water, the gallic acid unites with the iron, and a black liquor results, from which the colour, in the form of an impalpable powder, is gradually precipitated. To prevent the latter effect, it becomes necessary to render the liquor viscid, or of greater specific gravity; and this is best effected by the addition of a gum which is perfectly soluble in water, as this gum, besides keeping the black feculę; suspended in the liquor, serves also to prevent the ink from sinking or spreading on the paper, and likewise to defend it, in the manner of a varnish, from the action of the air. Ink may therefore be regarded as merely a gallate of iron, combined with a little mucilage. It follows, from this view of the matter, that the same, or very nearly the same, kind of black liquid may be produced from a great variety of substances, and, therefore, to make
2. Common Black Writing Ink. - It becomes the business of the manufacturer to select such materials as will produce the required quality at the least cost to himself. It is commonly supposed that nut-galls are employed on a large scale for this purpose, but the low price at which common ink is sometimes sold per gallon, renders this improbable; and that such an expensive material (however good) is not necessary, the reader has only to consider that the dyer makes a variety of good blacks without it. Of all known vegetable matters, sumach approaches nearest to galls, and forms a very cheap substitute; combined with the sulphate of iron (green copperas) it makes a very rich black ink, but it requires some peculiar management to prevent its becoming thick. Logwood, from the great affinity of its colouring matter to the oxide of iron, renders it a most desirable substitute for galls. It is well known to be partially used with galls in making ink; but very good common ink may be made from it without any other astringent matter.
Valonia, the barks of the oak, chestnut, and many other trees, may be very advantageously applied as useful substitutes for galls in making common ink, and are well deserving of the attention of the manufacturer who may not be acquainted with their properties.
A good common ink is made in the following manner: Take 8 ounces of Aleppo galls, in coarse powder, and 8 ounces of logwood, in thin chips; boil these in six quarts of soft water for an hour, and supply the waste from evaporation by the addition of fresh water; strain the decoction through a hair sieve, and then add 5 ounces of sulphate of iron, and 3 ounces of gum Senegal, of ordinary quality. Stir the mixture until the latter is dissolved, then let it subside for twenty-four hours, after which, decant the ink, and preserve it in bottles of glass or stone ware for use. This recipe, it is evident from the preceding remarks, may be considerably varied without material prejudice to the quality of the article; but it should be borne in mind that galls possess more intrinsic value (without reference to their prime cost) than their substitutes, as a given weight of them yields a greater quantity of black precipitate than any of the others; the current price, as well as the quality of the galls, will therefore have to be duly estimated, and in apportioning the substitute a greater quantity must be used.
3. Best, or Japan Ink. - M. Ribaucourt, who has paid particular attention to the process of making black ink, has drawn the following inferences from his experiments. That logwood, from its disposition to unite with the solutions of iron, is a valuable ingredient in the making of ink, rendering it not only of a very dark colour, but less capable of change from the action of acids or of the air. That sulphate of copper, in a certain proportion, gives depth and firmness to the colour of the ink. That gum has all the advantages we have before named. That sugar (although it has some bad qualities) is of use in giving a degree of fluidity to the ink, which permits the dose of gum to be enlarged beyond what the ink would bear without it. That water is the best solvent. From these considerations M. Ribaucourt has given the following directions for the composition of good ink, namely, 8 ounces Aleppo galls, 4 ounces logwood, 4 ounces sulphate of iron, 3 ounces gum arabic, 1 ounce sulphate of copper, and 1 ounce of sugar candy The galls and logwood to be boiled in 12 lbs of water, till reduced to 6 lbs. and after straining, the other ingredients are to be added.
This ink flows from the pen of a jet black, and from the gum being in greater proportion to the liquid than in the previous recipe, the writing dries with a gloss upon it; hence it has been called Japan ink. If it is desired to give it more gloss, the gum may be increased, to which some more sugar must be added to give it equal fluidity; but an excess in the latter ingredient renders papers written upon with it liable to stick together, upon contracting the least dampness.
M. Desormeaux, jun. an ink manufacturer of Spitalfields, gave an excellent recipe for making ink some time since in the Philosophical Magazine; but as his process does not differ essentially from those we have given, and as his observations are confirmatory, as far as they extend, of our own, we shall only notice the points of difference in his communication. He directs the sulphate of iron to be calcined to a whiteness, and employs coarse brown sugar instead of sugar-candy, the acetate of copper instead of the sulphate, and only in one-fourth the quantity; and recommends the ink to be agitated twice a day for a fortnight before it is poured from the dregs and corked up for use. These variations appear to be judicious and deserving of imitation.