CHAPTER XIII.
STUDY OF INK. Forty Centuries of Ink | ||
13. CHAPTER XIII.
STUDY OF INK.
INVESTIGATIONS BY STARK OF INK QUALITIES COVERING A PERIOD OF TWENTY-THREE YEARS—ABSTRACT FROM HIS REPORT OF 1855—DR. CHILTON EXPERIMENTS IN NEW YORK CITY 1856—ACTION OF THE PRUSSIAN GOVERNMENT IN 1859 AND EMPLOYMENT OF AN OFFICIAL INK—WATTENBACH'S GERMAN TREATISE ON THE ARCHIVES OF THE MIDDLE AGES—WILLIAM INGLIS CLARK ATTEMPTS TO PLACE THE MANUFACTURE OF INK ON A SCIENTIFIC BASIS—SUBMITS HIS VALUABLE RESEARCHES AND DEDUCTIONS TO THE ENINBURGH UNIVERSITY IN 1879—SCHLUTTIG AND NEUMANN IN 1890 ESTABLISH A STANDARD FORMULA FOR IRON AND GALL INK—NAMES OF SOME INK INVESTIGATORS OF THE NINETEENTH CENTURY.
DR. JAMES STARK, a famous chemist, submitted the results of twenty-three years of investigations of writing inks in a paper read by him in 1855 before the Society of Arts, in Edinburg, Scotland. The following is the abstract as printed by the London Artisan at the time:
Professor Leonhardi, of Dresden, who had given much attention to the subject of inks, introduced in 1855 what he termed a new ink, and named it "alizarine ink," alizarin being a product obtained from the madder root, which he employed for "added" color in a tanno-gallate of iron solution. It possessed some merit due to its fluidity, and for a time was quite popular, but gradually gave place to the so-called chemical writing fluids; it is now obsolete.
Champour and Malepeyre, Paris, 1856, issued a joint manual, "Fabrication des Encres," devoted almost exclusively to the manufacture of inks and compiles many old "gall" and other ink formulas.
In 1856 Dr. Chilton of New York City published the results of ink experiments which he had made. The accompanying extracts are taken from the local press of the month of April of that year:
While the information sought to be conveyed in the last statement may be in some respects correct, it must be remembered that most of the MSS. extant dating before the thirteenth century were written in "Indian" ink, while the great majority of those of the last two hundred years were not; and this fact alone would account to some extent for the differences mentioned.
The German (Prussian) government in 1859, as the result of an investigation, employed what they termed "Official Ink of the First Class," i. e., a straight tanno-gallate of iron ink without added color; and if permanence were required as against removal by chemicals, it was accomplished by writing on paper saturated with chromates and ultramarine.
In 1871 Professor Wattenbach of Germany published a treatise entitled "Archives during the Middle Ages," which has some valuable references to the color phenomena of inks.
William Inglis Clark in 1879 submitted to the Edinburgh University a thesis entitled "An Attempt to Place the Manufacture of Ink on a Scientific Basis," and which very justly received the commendation of the University authorities. His researches and rational deductions are of the greatest possible value judged from a scientific standpoint. The introduction of blue-black ink is a phase of the development towards modern methods which he discusses at much length.
The object of adding a dye in moderation, he asserts, is to give temporary color to the ink and where indigo-paste is used, it has been assumed that it kept the iron gallo-tannate in solution, whereas any virtue of this kind which indigo-paste possesses is more likely due to the sulphuric acid which it contains than to the indigo itself. The essential part of the paste required is the sulpho-indigodate of sodium, now commonly called indigo-carmine. He further remarks that the stability of an ink precipitate depends upon the amount of iron which it contains and which on no account should be less than eight per cent; he adds rightly, if gallic acid be preferably used in substitution for tannin, "no precipitate is obtained under precisely similar conditions." This point followed up explains in a measure why a gall infusion prepared with hot water is not suitable for a blue-black, while a cold water infusion is. In the latter case a comparatively small percentage of tannin is extracted from the galls, while much is extracted with hot water and the consequence is, on adding the indigo blue the
Dr. Clark's investigations seek to demonstrate the superiority of tannin and gallic acid over infusions of the natural galls, and he undertakes to determine the correct ratio of tannin and sulphate of iron to be used as ink. His experiments in this line show that:
- 1. The amount of precipitate increases as the proportion of iron to tannin is increased.
- 2. The composition of the precipitate is so valuable as to preclude the possibility of its being a definite body. Increase of iron in the solution has not at first any effect on the composition of the precipitate, but afterwards iron is found in it in greater but not proportional amount.
- 3. At one point the proportions of iron in the precipitate and in solution are the same, and this is at between 6 and 10 parts of iron to 100 parts of tannin.
- 4. The proportion of iron in the precipitate varies greatly with the length of time the ink has been exposed. At first the precipitate contains 10 per cent of iron, but by and by a new one having only 7.5 per cent is formed, and in from forty to seventy days we find one of 5.7 per cent. Simultaneously iron increases in the ink (proportionate to the tannin).
- 5. The results show, and practice confirms, that
16 parts of iron (80 ferrous sulphate) and 100 parts of tannin are best for ink manufacture.129
The research now travelled in a direction which accumulating experience showed to be obligatory. Blue-black tannin ink lost color, and the reducing nature of the tannin tended to the formation of a highly objectionable precipitate in the ink, which made writing anything but a pleasure. These two faults were doubtless linked together in some way and seemed not to exist when gallic acid was used, for ink so made was found to precipitate only after a long exposure, it required no free acid to keep the precipitate in solution, and retained the indigo blue color for a long time; alkalis did not decompose the ink, and provided blacker and more permanent writing. Determination of the correct proportions of gallic acid and ferrous-sulphate was the subject of prolonged experiments conducted on similar lines to those already detailed. The conclusions as to precipitation were also similar. Thirty parts of iron (150 of ferrous-sulphate) and 100 parts of gallic acid were found to be the most suitable proportions for ink-making. It is advisable, however, not to discard tannin altogether, owing to the slow blackening of the gallic acid ink, and a little tannin gives initial blackening and body, while it is absolutely necessary for copying ink. Initial blackness can also be ensured by oxidizing 21 per cent of the ferrous-sulphate without adding the extra acid necessary to the formation of a ferric salt.
The concluding portion of his research is devoted to the influence of sugar upon the permanence of ink, and the results of the experiments are summed up in the following sentences: "It would be injurious to add 3 per cent of sugar to a tan in ink, while from
Chen-Ki-Souen, "Lencre de China," by Maurice Jametel, appeared in Paris in 1882, but as the title indicates, it is the old "Indian" or Chinese ink that is discussed.
Schluttig and Neumann in 1890 issued their Edition Dresden on the subject of "Iron and Gall inks." In this valuable work is to be found the formula which has been generally adopted as the standard where one is used for tanno-gallate of iron ink.
The investigations of other scientific men like Lepowitz, Booth, Desormeaux, Chevreuse, Irvine, Traille, Böttger, Riffault, Precht, Nicholés, Runge, Gobert, Penny, Arnold, Thomson (Lord Kelvin), Davids, Kindt, Ure, Wislar and many more who have dealt with the chemistry of inks, present to us some testimony during a considerable portion of the nineteenth century of the efforts made to secure a good ink.
CHAPTER XIII.
STUDY OF INK. Forty Centuries of Ink | ||