To Dye a Mallard’s Feather for the Green Drake, and Little Yellow May Dun
Boil the feathers in the mordant bath of alum already described.
Then boil them in an infusion of fustic to produce a yellow, and subdue the brightness of this yellow by adding copperas to the infusion.
It is better to add a little of the indigo paste to this dye. It gives a brighter, clearer tone of color.