Have the feathers will cleaned and rinsed, bleaching being not
required, prepare a bath with three per cent. alum (of the weight of
feathers), at 170° F., add indigo carmine, bordeaux and azo yellow,
according to sample, and dye to shade while slowly raising the
temperature to near the boiling point, but bring not to boil, but
continue until the indigo carmine is well up. A less fast color is
obtained with archil, indigo carmine and picric acid. When finished
dyeing, rinse, starch and dry as usual.
The dyestuffs for brown being nearly the same for all shades, while the
depth and tone of the color is produced by differently proportioning
the quantities of the different dyestuffs and the time of dyeing, it
is advantageous to have the solutions of dyestuffs near by on hand;
it is advisable, however, if good work is intended, to always filter
before using solutions which have been standing for some time. This
precaution is necessary, because from most solutions, if allowed to
stand for a day or longer, some dyestuff which was not dissolved but
only suspended in the liquid, separates out forming a more or less
copious sediment which, if it passes into the dye bath, settles upon
the feathers causing spots or streaks of a different shade than the
rest of the feathers.