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.