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.