By using some of the methods of the calico printer, it is possible to employ these dyes, with some success, for stencilling. But even for this purpose, excepting, perhaps, on silk, the modern Vat colors are more convenient, as well as being infinitely more permanent to light.
Disadvantages.—The chief drawback to the use of these dyes is that they are not fast to light. Several of them—Methylene Blue, for instance, and Methylene Heliotrope O (Metz)—are fairly fast, but the rest, especially in light shades, and on transparent or translucent fabrics, are liable, when exposed to sunlight for any length of time, to alter their shade to a very marked degree.
For dark shades this is not so noticeable, for, when goods are strongly colored, the effect of the sunlight on at least the deeper portions of the fibre is largely counteracted by the color of the goods themselves. So, too, an opaque material, like leather, will hold the same shade of color distinctly longer than silk or, especially, artificial silk, where the sunlight strikes through and through the fibre, without any protection at all. But, generally speaking, these dyes will not stand strong sunlight.
Nor are the shades of these Basic dyes, as a rule, as attractive as those of other classes. The strong and brilliant, not to say coarse, shades of Methyl Violet, Malachite Green, Aniline Red, and the rest, which created such a sensation when they first appeared in the early sixties, were the particular colors which provoked John Ruskin to vehement, if not unparliamentary remarks. When unmixed they certainly do harrow the feelings of those artistically inclined, as much now as then. They are rarely seen now, for the taste of the public has been sufficiently educated to make a demand for softer shades. As before explained, nothing is easier than to soften these fierce, harsh colors to most beautiful and harmonious tints by mixing into them a mere trace of their complementaries.
Advantages.—In spite of all that can be said against them, these cheap, brilliant, and very powerful dyes are not to be despised, and should still be found in the outfit of a well-equipped dyer. For straw, raffia, chips, willow, and other materials used so largely for hats and for basket-work, these dyes are distinctly valuable, and, if supplemented by fast Acid colors for light shades, or for particularly fast effects, will be found satisfactory enough. So, too, for leather they will be found extremely useful, excepting where delicate shades, fast to light, are required.
Some kinds of artificial silk, also, especially those made from nitro-cellulose and hence possessed of acid properties, dye far better with these than with any other dyes, although, as explained above, the colors will be far from permanent.
For the craftsman, the fastness to washing of these dyes is a matter of very little importance, because they are used by him so exclusively upon materials such as basketry, leather, and artificial silk, which are never exposed to rough handling in boiling soap and water.
As regards their fastness to light, the greater number of these must be classed as belonging to the fourth class, i.e., distinctly fugitive in character. On the other hand, some special ones can be selected from the group which are not only distinctly faster than the rest, but are fast enough to be well up in the third class, or can at a stretch, be placed in the second class, i.e., can be considered as satisfactory, at any rate, against any but very severe exposure.
The Fastest Basic Colors.—Among these may be placed the well-known dyestuff, Methylene Blue, perhaps the most satisfactory of the whole class. A very good color also is Methylene Heliotrope O (Metz), which, while less brilliant, is far faster than the many brands of Methyl Violet, Hofmann’s Violet, and the rest, which to most dyers are the characteristic basic violets.
For blacks, many composite dyes are on the market, made by the different color houses, known as Leather Blacks. These are fast enough, for deep shades, but not to be trusted when thinned down to form greys. The fastest individual basic black is Diazine Black, (Kalle), and this should be used for the lighter shades.