DYEING is a very ancient art; from the earliest times of the ancient civilisations till within about forty years ago there had been no essential change in it, and not much change of any kind. Up to the time of the discovery of the process of Prussian-blue dyeing in about 1810 (it was known as a pigment thirty or forty years earlier), the only changes in the art were the result of the introduction of the American insect dye (cochineal), which gradually superseded the European one (kermes), and the
American wood-dyes now known as logwood and Brazil-wood : the latter differs little from the Asiatic and African Red Saunders, and other red dye-woods; the former has cheapened and worsened black-dyeing, in so far as it has taken the place of the indigo-vat as a basis. The American quercitron bark gives us also a useful additional yellow dye.
These changes, and one or two others, however, did little towards revolutionising the art; that revolution was left for our own days, and resulted from the discovery of what are known as the Aniline dyes, deduced by a long process from the plants of the coal-measures. Of these dyes it must be enough to say that their discovery, while conferring the greatest honour on the abstract science of chemistry, and while doing great service to capitalists in their hunt after profits, has terribly injured the art of dyeing, and for the general public has nearly destroyed it as an art. Henceforward there is an absolute divorce between the commercial process and the art of dyeing. Any one wanting to produce dyed textiles with any artistic quality in them must entirely forgo the modern and commercial methods in favour of those which are at least as old as Pliny, who speaks of them as being old in his time.
Now, in order to dye textiles in patterns or otherwise, we need four colours to start with - to wit, blue, red, yellow, and brown ; green, purple, black, and all intermediate shades can be made from a mixture of these colours.
Blue is given us by indigo and woad, which do not differ in colour in the least, their chemical product being the same. Woad may be called northern indigo; and indigo tropical or sub-tropical woad.
Note that until the introduction of
Prussian blue about 1810 there was no other blue dye except this indigotine that could be called a dye ; the other blue dyes were mere stains which would not bear the sun for more than a few days.
Red is yielded by the insect dyes kermes, lac-dye, and cochineal, and by the vegetable dye madder. Of these, kermes is the king ; brighter than madder and at once more permanent and more beautiful than cochineal: the latter on an aluminous basis gives a rather cold crimson, and on a tin basis a rather hot scarlet (e.g. the dress-coat of a line officer). Madder yields on wool a deep-toned blood-red, somewhat bricky and tending to scarlet.
On cotton and linen, all imaginable shades of red according to the process. It is not of much use in dyeing silk, which it is apt to " blind " ; i.e. it takes off the gloss. Lac-dye gives a hot and not pleasant scarlet, as may be noted in a private militiaman's coat. The French liners' trousers, by the way, are, or were, dyed with madder, so that their countrymen sometimes call them the " Madder-wearers " ; but their cloth is somewhat too cheaply dyed to do credit to the drysaltery.
Besides these permanent red dyes there are others produced from woods, called in the Middle Ages by the general name of " Brazil" ; whence the name of the American country, because the conquerors found so much dyeing-wood growing there. Some of these wood-dyes are very beautiful in colour ; but unluckily they are none of them permanent, as you may see by examining the beautiful stuffs of the thirteenth and fourteenth centuries at the South Kensington Museum, in which you will scarcely find any red, but plenty of fawn-colour, which is in fact the wood-red of 500 years ago thus faded. If you turn from them to the Gothic tapestries, and note the reds in them, you will have the measure of the relative permanence of kermes and " Brazil," the tapestry reds being all dyed with kermes, and still retaining the greater part of their colour. The mediaeval dyers must be partly excused, however, because " Brazil' is especially a silk dye, kermes sharing somewhat in the ill qualities of madder for silk ; though I have dyed silk in kermes and got very beautiful and powerful colours by means of it.
Yellow dyes are chiefly given us by weld (sometimes called wild mignonette), quercitron bark (above mentioned), and old fustic, an American dye-wood. Of these weld is much the prettiest, and is the yellow silk dye par excellence, though it dyes wool well enough. But yellow dyes are the commonest to be met with in nature, and our fields and hedgerows bear plenty of greening-weeds, as our forefathers called them, since they used them chiefly for greening blue woollen cloth ; for, as you may well believe, they, being good colourists, had no great taste for yellow woollen stuff. Dyers'-broom, saw-wort, the twigs of the poplar, the osier, and the birch, heather, broom, flowers and twigs, will all of them give yellows of more or less permanence. Of these I have tried poplar and osier twigs, which both gave a strong yellow, but the former not a very permanent one.
Speaking generally, yellow dyes are the least permanent of all, as once more you may see by looking at an old tapestry, in which the greens have always faded more than the reds or blues ; the best yellow dyes, however, lose only their brighter shade, the " lemon " colour, and leave a residuum of brownish yellow, which still makes a kind of a green over the blue.
Brown is best got from the roots of the walnut tree, or in their default from the green husks of the nuts. This material is especially best for " saddening," as the old dyers used to call it. The best and most enduring blacks also were done with this simple dye-stuff, the goods being first dyed in the indigo or woad-vat till they were a very dark blue and then browned into black by means of the walnut-root. Catechu, the inspissated juice of a plant or plants, which comes to us from India, also gives rich and useful permanent browns of various shades.