All solutions of dyestuffs, as well as of chemicals, ought to be carefully filtered, and decoctions of woods, etc., strained before adding them to the bath; never add dyestuffs, drugs or chemicals in substance to any bath, in order to prevent solid particles from settling upon the feathers.
Never add all the dyestuff probably required or prescribed by a recipe to the dye-bath at one time, but in several small quantities, each time after taking up the feathers, stir the bath after making the addition, re-enter the feathers and watch the progress of the dyeing carefully; when approaching the desired shade, add the dyestuff very cautiously, by drops if necessary, particularly with mixed colors, such as modes.
Sample in proper time, and take not a whole feather for it, but pull off two or three fibres from the lower part of a feather, dry them quickly by squeezing between dry muslin, match, correct the bath and finish dyeing.
While drying keep the feathers as much as possible in constant motion, shake and beat them.
Do not interrupt operations, if it can be avoided, but do the work rapidly and continuously, without pausing.
Keep every utensil scrupulously clean.
THE END.