III. Take a hot bath, upon which violet has been dyed, and refresh it with some solution of methyl violet, 5 B., and a few drops of sulphuric acid, or prepare a hot bath with the same ingredients, and indigo carmine, according to shade; or, instead of indigo carmine, indigo substitute, fast blue B. A., and indigotine; preferably, however, use indigo carmine, which develops more slowly, and therefore is surer to give better results, while the aniline dyestuffs run up more rapidly, and are apt to dye unevenly, unless their solutions are added gradually and the feathers handled quickly and carefully.
LIGHT YELLOW.
I. Light yellow is comparatively very little in demand for ostrich feathers, and scarcely used for trimming hats of children and young misses as a set-off for other colors. To produce it, prepare a pretty hot bath with a little sulphuric acid, so as to give it a slightly acid taste, add very little quinoline yellow, lay down the feathers in the bath for one-half hour, turning and agitating them from time to time, lift, rinse and dry. For this color, as well as for light blues and roses, the feathers must be perfectly white. (For this dye the quinoline yellow manufactured by the Actien Gesellschaft fuer Anilin Fabrikation, Berlin, is specially suitable). As the purity of all light shades of delicate colors greatly depends upon the purity of the water, it is advisable to bring the bath, before preparing it, to boil with some bran and chloride of tin and skim it off well.
MEDIUM YELLOW.
Various shades of yellow can also be produced with the old natural dyestuffs, which are not, however, equal in brilliancy to the foregoing described colors. The feathers must be bleached for these as well as for any clear color, which would be materially impaired by an impure bottom; still developed grays may be employed. After scouring and thoroughly rinsing the feathers, prepare a cold bath of alum, about one ounce to one gallon of clear water, or of acetic acid; lay the feathers down until well opened, so that the liquid can uniformly act upon all parts, for one hour. Then take them out, squeeze and centrifugate them, and dye the shade upon a fresh warm bath with the required quantity of flavine, decoction of color or of fustic; lift, rinse and starch as usual.
Or, dissolve a sufficient quantity of turmeric in boiling water, filter and enter the feathers while the filtrate is still well hot. Agitate them for five minutes, then take them up, add to the bath a small quantity of tartaric acid, this to promote its dissolution; then re-enter the feathers, work them again for five minutes, lift, rinse in cold water, and dry.
If these colors are to have a light reddish or warmer tone, add, when nearly done, some anotto to the dye bath.
DARK YELLOW.
Bleached grays answer for this color as well as naturally white feathers. Scour and rinse them well. Prepare a bath, feebly acidulated with sulphuric acid, and add the filtered solution of two and one-half per cent. of the weight of feathers, dark yellow, (manufactured by the Leipziger Anilin Fabrik, formerly Bayer & Kegel). Enter the feathers in the cold and work them diligently until the color is well up, then raise the temperature slowly to 170° F., dye to shade, lift, rinse in clear cold water, starch and dry.