I. For this elegant color take naturally white or bleached gray
feathers, scour and rinse them well. Prepare a hot bath with five per
cent., of the weight of feathers, bisulphate of soda, to which add,
as required, filtered solutions of fast yellow, indigo carmine and
ponceau G. Enter the feathers at 170° F., work them for ten or fifteen
minutes and raise the temperature slowly to near the boiling point. Add
the dyestuffs in small quantities gradually, making the additions only
when the dyestuff of the bath has been completely absorbed, and then by
drops so as to be able to correct the color without waste of dyestuff.
Bear in mind, that the indigo carmine dyes up slowly and requires a
high temperature. An easier process is, therefore, the following:
II. After cleaning and rinsing well, prepare a bath at 170° F., with
four per cent. bisulphate of soda, to which add gradually in small
quantities, as required, some nigrosine, azo orange and a little
mandarin or nigrosine, alkaline blue and fuchsine S., rinse, starch and
dry.