This color is preferably dyed upon unbleached gray feathers. Scour and
rinse them, prepare a decoction of green walnut husks or of sumac; lay
the feathers down in it for two hours, working them from time to time;
then add some decoction of logwood and dye to shade at 170° F., or
indigo carmine and dye to shade while slowly raising the temperature to
near the boiling point. Rinse, squeeze, starch and dry.