Forty Centuries of Ink / Or, A chronological narrative concerning ink and its backgrounds, introducing incidental observations and deductions, parallels of time and color phenomena, bibliography, chemistry, poetical effusions, citations, anecdotes and curiosa together with some evidence respecting the evanescent character of most inks of to-day and an epitome of chemico-legal ink.

by David Nunes Carvalho

ALL inks when first placed on paper are of course in a fluid state. Gradual evaporation of moisture causes a change not only in color but in the case of the iron and gall inks, in their chemical constitution, being immediately affected by their environment, whether due to the character of the paper on which they rest, the kind or condition of the pen used, or most important of all, the elements. Those who use the black inks and chemical writing fluids will have noticed these characteristics. The pale brown, blue or green as first written, and the gradual change after a short period to an approaching blackness, are reactions due largely to atmospheric conditions, the oxygen uniting with that for which it has affinity and instantly beginning with TIME to make its march, producing natural phenomena, which can be only superficially imitated but never exactly reproduced. When we further take into consideration that the forger cannot always know of the circumstances which surround the placing of original ink on paper and that be cannot manufacture the TIME which has already elapsed, it is not strange that attempted fraud can often be made evident and complete demonstrations given of the methods employed.

With the passage of time, the particles in some inks which are held together on the paper by gummy vehicles, commence to disintegrate and change from intense black to the brown color of iron rust, the "added" color which of itself is fugitive in character, soon departs; the vegetable astringent separating from the iron salt decays gradually and disappears and finally terminates in a mere stain or dust mark which can be blown off the paper. Sometimes, the written surface of such paper can be treated by carefully moistening it with a decoction of nut-galls or its equivalent in the presence of a weak acid, then if any iron be present, a measurable degree of restoration of color will ensue and remain for a short period.

Again, the discoloration of an iron ink may be due to the character of the paper; if of the cheaper grades and the bleaching compounds employed in their manufacture are not thoroughly washed out, then the ink not only begins to absorb oxygen from the atmosphere but the chlorine in the paper attacks it and the process of destruction is thereby hastened.

The introduction of acid into ink has two purposes, one to secure more limpidity, and the other to cause it to penetrate the paper and in this way bind together the constituent particles of both ink and paper. Most of the chemical writing fluids of this decade carry a superabundance of acid in their composition, which in time will burn through the paper and ultimately destroy it.

All tanno-gallate of iron inks require some vehicle to hold their particles in a state of suspension, otherwise there would be precipitation and such an ink could not be used. To meet this requirement a variety of gums are employed by manufacturers, gum acacia being the principal one. Its purpose is threefold—as before stated, to hold the ink particles in suspension—to prevent the ink from flowing too rapidly, and after drying WITHOUT blotting, to act as an envelope to encase the now fixed ink and prevent or interfere with its absorption of an excess of oxygen. The longer these latter conditions obtain the longer will the ink retain its pristineness, its durability and permanence. The "time proved" ink-written specimens of five hundred years or more ago which continue to retain their original intense black color and "glossy" appearance, do not, however, yield any evidence of the use of vegetable gums in their composition. Where such instances have been noticed the gloss is invariably missing. But, where ANY gloss is present, it was and is because of the employment of isinglass (fish-glue) as the vehicle to hold the ancient ink particles.

Hence the variations of color seen in ancient paper writings, as already stated, were due not only to possible imperfect admixtures of the component parts of the inks, but to the use of vegetable gums in their preparation. In the course of time these have been absorbed by moisture which hastened disintegration, causing a gradual disappearance of their original blackness and gloss and finally a return to the rusty color of oxidized iron.

It therefore follows, my observations and deductions being correct, the older a writing made with tanno-gallate of iron ink, where isinglass is the binder, and which has not been "blotted," the harder and more impervious and irresponsive it becomes to the action of the natural elements or of chemical reagents.

The truths demonstrated in this proposition cannot be denied. They fortify as certain that a properly proportioned mixture in water of an infusion of nut- galls or gallo-tannic acid and sulphate of iron, with isinglass as the vehicle to bold the particles in a state of suspension, if written with on good paper and allowed to dry without blotting, in a short time becomes encased or enveloped in such vehicle, which is thereby rendered substantially insoluble and absolutely prevents any extensive oxidation. Also, as a further consequent result, there is chemically created an unchangeable and continuing black color more permanent and durable than the substance on which it appears.

With a sample of standard commercial chemical writing fluid, write on "linen" paper without blotting it; in thirty hours, if exposed to the air and from three to five days if kept from it, the writing should have assumed a color bordering on black; it becomes black at the end of a month under any conditions, and so continues for a period of about five or six years, when if examined under a lens of the magnification of ten diameters, there will be a noticeable discoloration of the sides or pen tracks which slowly spreads during a continuing period of from ten to fifteen years, until the entire pen marks are of a rusty brown tint. A species of disintegration and decay is now progressing and when approximately forty years of age, has destroyed all ink qualities.

If, however, "chemical writing fluid" is first treated by exposure to the fumes of an ammoniacal gas, a "browning" of the ink occurs, not only of the pen tracks but of the entire ink mark. If examined now with a lens, the ink is found to be thin enough to permit the fibre of the paper to be seen through it, thus indicating artificial age. Furthermore, if a 20 per cent strength of hydrochloric acid be applied, the "added" color (usually a blue one) is restored to ITS original hue; alike experiment on "time" aged ink gives only the yellow brown tint of pure gall and iron combinations, the "added" color having departed caused by its fugitive characteristics. Again, if a solution of chlorinate of lime or soda be applied, the ink mark is instantly bleached, where in the case of honest old ink marks, it takes considerable time to even approximate a like result.