HELIOTROPE AND LILAC.
I. These colors being simply medium and light shades of violet, proceed as for the latter color, selecting for heliotrope the bluish brands of methyl violet, and for lilac the red touch mark. The dyebath is acidified with a little tartaric acid, so as to give it a feeble sourish taste and dyeing done at hand-heat until a level color is obtained with very little solution of the dyestuff, and more of it gradually added, while the temperature is raised to nearly boiling, as required for the shade to be produced. Or,
II. Prepare the dyebath simply of cold water acidulated with a little sulphuric acid, add a few drops of the filtered solution of methyl violet (4 B. for heliotrope), and dye to shade without heating. In both cases rinse after dyeing, pass through a bath of raw starch and dye as usual.
CREAM.
I. The lightest shade of this delicate color can be produced upon naturally gray ostrich feathers by simply bleaching them; this color, however, is extremely sensitive, probably because the action of peroxyd of hydrogen continues under the influence of the oxygen of the air. Bleached grays require, therefore, dying as well as naturally white feathers. The feathers being well scoured and rinsed, prepare in a white basin (preferable to the copper pans, because the coloring of the dyebath is easier and more correctly discerned over the white bottom) a bath of pretty hot water, to which add a pinch of tartaric acid, and a little decoction of turmeric or solution of fast aniline yellow or of azo yellow, but only enough to give the water a light tint; work the feathers in it for four to six minutes. Then sample and correct, if necessary, by adding more dyestuff solution. The shade being obtained, pass through cold water, starch and dry us usual.
II. Prepare in a white basin a handwarm bath with three or four drops of sulphuric acid and a few drops of the filtered solutions of picric acid, fast aniline yellow, quinoline yellow, or mandaric yellow extra, but preferably turmeric which dyes up more evenly than the other dyestuffs. Enter the feathers and agitate them for fifteen or twenty minutes; then lay them down in the bath for one-half hour longer to insure a level dye; lift, draw through lukewarm water, starch and dry.
WHITE AND BLACK.
Science teaches that white is the source of light or the product of combination of all other colors, because the light of the sun, which is assumed to be white, when broken up by means of a prism, shows in its image reflected upon a white plain, the three primary, and three secondary colors with the uncounted number of intermediary products of combinations of fractions of the primary colors forming the transition from one to the other, which can be perceived by the eye but not exactly separated from one another, but may quantitatively determined to an approximate degree of accuracy. Black, on the other hand, is described as the absence of all light, and it is denied, therefore, by theory a place among the colors.
Practice asserts the direct contrary of the theory developed by science by way of conclusion. While philosophers assert that they have succeeded in producing white light by the combination of lights of the various colors, for which combination, however, they give no formula, no dyer with the greatest patience and with the most subtile proportioning of dyestuffs, giving pure reproductions of the primary colors as seen in the spectrum or image of the broken sunbeam, can ever be able to produce anything of a color approaching white. But every dyer knows how to produce white by bleaching, that is, by the destruction of all color. And this operation is comparatively simple and easy to perform, since the great achievements of modern chemistry have placed into the hand of the dyer the most energetic and effectious color destroying agents. The ostrich feather dyer of to-day is able to convert naturally gray and even black feathers into nearly pure white, which undertaking his father would have called the boast of a deranged mind and an absolute physical impossibility. And with the aid of a complementary color dyed upon the bleached feathers the tint remaining upon them is obliterated, or neutralized, which operation is generally called "white dyeing," although certainly white cannot be "dyed" with a blue or violet dyestuff as little as blue or violet can be produced with a yellow dyestuff.