BLACK AND BLUE1 BY WILDER D. BANCROFT
I n a recent paper,2 I have pointed out that a possible reason for the apparent confusion between blue and black at the time of Homer was that blue may have been considered unconsciously as an intermediate stage between gray and black. I have just stumbled on what appears to be another case of confusion between blue and black in an article on indigo3 published over a century ago. “What Dioscorides calls indicon and Pliny and Vitruvius indicum, I am strongly inclined to believe to have been our indigo. It was a blue pigment brought from India, and used both in painting and in dyeing. When pounded, it gave a black powder; and when diluted in water it produced an agreeable mixture of blue and purple. It belonged to the costly dye-stuffs, and was often adulterated by the addition of earth. . . . Everything said by the ancients of indicum seems to agree perfectly with our indigo. The proper country of this production is India; that is to say, Gudcharot or Gutscherad, and Cambaye or Cambaya, from which it seems to have been brought to Europe since the earliest periods, It is found mentioned, from time to time, in every century; it is never spoken of as a new article, and it has always retained its old name; which seems to be a proof that it has been used and employed in commerce without interruption.” Beckmann states elsewhere in his article that “I have long made it a rule and prescribed it to others, in explaining any object mentioned by the ancients never to admit, without the strongest proofs, that the same article is denoted by different appellations. This, it is true, has been often done. By these means the small knowledge we possess of a thing that occurs under one name only may be increased. A wider field may thus be opened for conjecture, and more latitude may be given to the imagination; but at the same time one may fall into groundless explanations and hazard assertations, which, with whatever caution and learning proposed, will, on closer examination, be found either false or highly improbable. According to this rule, I have carefully endeavoured not to suffer myself to be so far misled by the respectability of my predecessors, as to consider the Indicum and Indicum nigrum of the ancients to be the same substance. On further research I find that the latter not only appears by the epithet to be different from indigo, but that it is China, or, as the Dutch call it, Indian ink. . . . This paper is a necessary consequence of experiments supported by a grant from the Heckscher Foundation for the Advancement of Research, established by August Heokscher a t Cornel1 University. * Bancroft: J. Phys. Chem. 28, 131 (1924). * Beckmann: “History of Inventions”, 103 (1814).
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“Pliny here enumerates all the materials which, in his time, were used for black ink. He, therefore, mentions two vitriolic substances, a slime or sediment (salsugo), and a yellow vitriolic earth (called also misy). Such minerals continued in use as long as men were unacquainted with the art of lixiviating the salt, and causing it to crystallize; or, in other words, as long as they had no vitriol-manufactories. He speaks also of lamp-black being made in huts built for the purpose, which are described by Vitruvius, and from which the smoke of burning pine-wood was conveyed into a close apartment. The article was certainly adulterated when soot, taken from the baths and other places where an open fire was maintained with wood of all kinds, was intermixed with it. It is very remarkable t.hat black from burnt refuse of grapes, noir de oigne, which at present our artists, and particularly our copper-plate printers, consider as the most beautiful black, was made even at that period. Germany hitherto has obtained the greater part of this article from Mentz, through Franckfort, and on that account it is called Franckfort black. Some is made also at Kitsingen, Markbreit, and Munich. For this purpose the refuse of the grapes is charred in a close fire, and being then finely pounded is packed into casks. Pliny observes, that it was asserted that from this substance one could obtain a black which might be substituted for indigo. Another pigment was bone black, or burnt ivory, which is highly esteemed even a t present. Besides these, continues he, there is obtained from India what is called Indicum, the preparation of which I have not yet been able to learn; but a similar pigment is made from the black scum of the dye pans, in places for dyeing black, and another kind is obtained from charred fir-wood finely pulverised. The cuttle-fish (sepia) likewise gives a black; but that however has nothing to do with the present question. He remarks in the last place, that every kind of black pigment is improved, or rather the preparation of it completed, by exposure to the sun; that is to say, after gum has been added to t’hat intended for writing, and size to that destined for painting. But that which was made with vinegar was more durable, and could not be easily effaced by washing. All this is very true. Our ink acquires a superior quality when exposed to the light of the sun in flat vessels. That vinegar renders black colours faster, is well known to our calico-printers; and those who wish to have good ink must employ in making it the brightest vinegar of beer. It is equally true, that every black pigment mixed up with gum or size can be sooner and easier washed out again with water. “A considerable part of what has hitherto been quoted from Pliny, may be found also in Vitruvius. The latter, in like manner, mentions huts for making lamp-black; he speaks also of ivory-black, and says expressly, that when it is properly made it not only forms a good colour and excellent ink, but approaches very near to Indicum. “Now I might here ask, whether it is at all probable that the learned Pliny and the practical connoisseur of painting, the architect Vitruvius, could consider and describe our blue indigo as a pigment which, like lamp-black, could be employed as a black colour and as ink? Is it credible that Pliny, if
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he meant blue indigo in the before-mentioned passage, would have said that he was not able to learn the preparation of it, when he expressly describes it, as he believed it to be, in the course of a few lines further? Would Pliny and Vitruvius, had they been acquainted with black indigo only, remark immediately after, that, when costly indigo could not be obtained, earth saturated with woad, consequently a blue earth, might be used in its stead? Is not allusion here made to a blue pigment, as was before to a black one? Is it not therefore evident, that the name of indicum was given to a black and also to a blue pigment brought from India? And if this be the case, is it not highly probable that the black indicum was what we at present call India ink, which approaches so near to the finest ivory-black, and black of wine lees, that it is often counterfeited by these substances, a preparation of which is frequently sold as Indian ink to unwary purchasers? Indian ink is in general use in India, and has been in all probability since the earliest ages. In India all artificial productions are of very great antiquity; and therefore I will venture to say, that it, is not probable that Indian ink is a new invention in India, although it may probably have been improved, and particularly by the Chinese. “To confound the two substances, however, called indigo (indicuni) a t that period was not possible, as every painter and dealer in colours would know that there were two kinds, a blue and a black. It has, nevertheless, occurred to me, that in the works of the ancients obscurity may have sometimes been avoided by the addition of an epithet; and I once thought I had found in Pliny an instance of this foresight; that is, where he names all kinds of colours-purpurissum, Indicum ceruleum, melinum, auripigmentum, cerussa. I conceived that in this passage our indigo was distinguished from the black indicum by the epithet ceruleum. But my joy at this discovery was soon damped by Hardouin, who places between Indicum and ceruleum a comma, which is not to be found in many of the oldest and best editions. I cannot, therefore, get rid of this comma; for it is beyond all dispute that ceruleum was the common appellation of blue copper ochre, that is, mountain blue. I shall now proceed to examine whether my observation be true, that the Greeks frequently used the term black indicum, when they meant to denote the black, and not the blue. “The term nigrum Indicuw occurs in Arrian, Galen, Paulus, Aegineta, and perhaps in the works of other Greek physicians; and as the Latin writers were acquainted with an Indicum which dyed black, there is reason to conjecture that this was the Indicum nigrum of the Greeks, though I should rather be inclined to translate this appellation by the words Indian black, in the same manner as we may say Berlin blue, Roman red, Naples yellow, Brunswick green, Spanish brown, etc; or I should as readily translate it Indian ink. Arrian introduces it along with other Indian wares. I do not indeed find that he makes any mention of indigo properly so called; but a complete catalogue of merchandise is not to be expected from him. Indicum, however, occurs once more in this author; but in the passage where it is found
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it is only an epithet to another article. Speaking of cinnabar, he adds, that he means that kind called Indian, which is obtained from a tree in the same manner as gum. I am inclined to think that he alludes to dragon’s blood, which on account of its colour was at that time called cinnabar. “Some have conjectured that what in Arrian is named laccos chromatinos was our indigo, which indeed might be classed among the lakes, according to the present meaning of that word. Others, however, understand by it gum lac. But I am unacquainted with any proofs that gum lac was known a t so early a period. I much doubt whether this meaning of the word lac be so old; and I must confess that the opinion of Salmasius appears to me highly probably, namely, that Arrian alluded to a kind of party-coloured garment. For, besides the grounds adduced by Salmasius, it deserves to be remarked, that in the passage in question different kinds of cloths, and no other articles, are mentioned. Besides, the epithet chromatinos is applied by the same writer, in the same sense to other kinds of clothing. It cannot, therefore, be said that Arrian mentions our gum lac, the origin of which word Salmasius endeavours to discover. ((In the works of Galen, which have not yet been sufficiently illustrated, I have found Indicum nigrum only four times. In a place there he speaks of diseases of the eyes, he extols it on account of its cleansing quality; and says it can be used for wounds, when there is no inflammation. I n another place, it occurs in three prescriptions for eye-salves. I have however endeavoured, without success, to find in this excellent writer an explanation of what he calls Indicum; though he has explained almost all the different articles then used in the materia medica. It appears, therefore, that the Greeks gave the name of Indicunz to our indigo, and also to Indian black or Indian ink. “It, however, cannot be denied that, in opposition to this opinion, considerable doubts arise. Many who think that the black indigo (nigrumIndicum) of Pliny and Vitruvius was not ink, but our indigo, remark, that things of a dark blue or dark violet colour were by the Greeks and the Romans frequently named black; and, therefore, that the blue indigo might in this manner be called black. But the examples adduced as proofs are epithets, applied by the poets to dark-coloured flowers. Because nature produces no black flowers, the poets, who are fond of everything uncommon, extraordinary, and hyperbolic, call flowers black, when they are of so dark a tint as to approach nearly to black. Thus clear and deep water is called black. It is, however, hardly credible that painters and dyers, who must establish an accurate distinction between colours, should have spoken in so vague a manner. Salmasius SUSpects that Nil and Nir, the Arabic names of Indigo, have arisen from the Latin word niger. “The objection, that Paulus Aegineta, the physician, in a passage where he refers to Dioscorides for the medical virtues of Indicum, applies to it the epithet black, seems to have more weight. It may be added also, that the virtues, in general, which Galen ascribes to the Indicum nigrum, appear to be similar to those ascribed by Dioscorides to Indicum; and the latter in one
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place, where he speaks of the healing of the wounds, uses only the expression Indicum, and not Indicum nigrum. It is particularly worthy of remark that Zosimus, the chemist, declares the hyacinth colour of the ancients, that of woad, and the Indicum nigrum, to be the same or similar. But to those who know on how slight grounds the ancient physicians ascribed medicinal qualities to many substances, it will not perhaps appear strange, that, in consequence of the same name, they should ascribe the same qualities to two different things. I t is not improbable that in cases of external injury, for which the Indicum nigmm was recommended, indigo and Indian ink might produce as much or as little effect. I should consider of far greater importance the opinion of the chemist Zosimus; but unfortunately his writings have not yet been printed. The period in which he lived is still uncertain, and it is not known whether all the chemical manuscripts which bear that name were written by the same author. “From what has been said, I think it may, at any rate, be inferred, that in the time of Vitruvius and Pliny indigo, as well as Indian ink, was procured from India, and that both were named Indicum. It is less certain that the Greeks called indigo Indicum, and Indian ink Indian black. Nay it appears that indigo, on account of the very dark blue colour which it exhibits both when dry and in the state of a saturated tincture, was often named Indian black.” It is interesting to note that the shading of blue into black is not unknown in the dye industry. Knecht, Rawson and Loewenthall state that naphthol black B dyes wool from dark blue to deep black, while Ganswindt2 points out that the black acid colors do not give a pure black on silk but dye a very dark blue even when used in fairly high concentrations. Even in this case there is some question as to the actual color for Matthews3 says that ‘(the acid dyes are principally used on silk for the production of fancy colors; the black acid dyes, though largely used on wool, have but little use on silk as it is not possible to produce as satisfactory a black with them as with logwood. The black acid dyes do not seem to properly fill the fiber so as to make it opaque to light, in consequence of which the color exhibits a slaty appearance, while with logwood (by reason of the relatively large amount of pigment mordant employed) the fiber is rendered opaque and the color produced is a full rich black.” Cornell University. “A Manual of Dyeing”, 558 (1910). “Theorie und Praxis der modernen Farberei”, I1 44 (1903).
