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.
II. A new light yellow, which is fast to light and air, is obtained by
products of Leonhardt & Co., at Manheim, viz: redarine and acme yellow.
Add to a hot bath of 170-190° F., a quite small quantity of redarine
and still less acme yellow; enter the feathers, manipulate for one-half
hour, take out, rinse and dry them with starch, and beat well out. This
color being extremely sensitive, the purification of the water for the
bath is as necessary as the most scrupulous cleanliness of utensils and
workshops.