After scouring and rinsing well, prepare a warm bath (100-120° F.) with five per cent., of the weight of feathers, bisulphate of soda, to which add solution of Victoria blue and of extract of archil, according to sample. Acid violet may be used, but requires a temperature near the boiling point, which ought to be avoided wherever possible in dyeing ostrich feathers. To be on the safe side, make the solutions of the dyestuffs of medium concentration, use only the clear of them, or better filter the same, and add it slowly and gradually first in small doses, finally by drops, for which purpose the use of a burette with squeeze-cock is recommendable.
SILVER GRAY.
Scour, respectively bleach, and rinse the feathers well clean, prepare a bath, work the solution of five per cent., of the weight of feathers, silver gray (Actein Gesellschaft fuer Anilin Fabrikation, Berlin), feebly acidulated with sulphuric acid; enter the feathers in the cold, work well to make the color dye up evenly; then raise the temperature slowly under diligent working, to 170° F., continue at this temperature for five to ten minutes, lift, rinse and dry.
BROWN.
The series of brown colors, partly produced by combinations of spectrum colors, partly of direct brown dyestuffs, presents a large range of modifications and shades, from a light rust brown or buff to nearly black, blueish, yellowish, reddish, olive brown, etc., and is in this respect only inferior to the non-descript endless variety of modes. With the exception of the very lightest shades, which require perfectly white feathers, they can be dyed upon half-bleached, and the deeper shades upon unbleached gray feathers; the dyer, must, however, in the latter case, bear in mind, that the gray bottom color always influences to a certain degree, the tone of the color that is to be dyed upon it. Nevertheless, as to the proportions of the dyestuffs to be employed for a given tone or shade cannot be given, because the tinctorial value of artificial dyestuffs is very changeable and not even constant with the same makers. Experience, skill and trial dyes must, therefore, guide the dyer in composing the baths for browns as well as for modes, the majority of the latter being modifications of brown. In general the following may be observed:
I. After scouring the feathers and rinsing them perfectly clean of the scouring material, whether soap or soda, prepare a bath of 170 to 190° F., to which add fifteen per cent., of the weight of feathers, bisulphate of soda, indigo carmine, extract of archil and azo yellow.
According to the proportionally greater or smaller quantity of either dyestuff added to the dyebath either browns are obtained, or olives, Russia green, reseda, or a variety of modes. The trouble with all colors into whose compositions indigo carmine enters is, that this dyestuff requires a comparatively high temperature to run up, preferably a boiling bath, which, however, is decidedly objectionable with ostrich feathers. To avoid this difficulty, the new acid Victoria blue is used instead of indigo carmine, and fuchsine S. instead of extract of archil. Victoria blue dyes up readily at a moderate temperature.
II. The feathers being scoured and rinsed clean, prepare a boiling bath with so much sulphuric acid as to give a feebly sour taste, and add fast aniline brown, turmeric, and indigo carmine or cloth-blue S., according to the tone and shade desired. Prepare the bath so that it shows exactly this tone of color which is to be dyed, and bring it to boil in order to produce a perfect mixture of the three dyestuffs, or rather their filtered solutions. Then chill the bath to about 120° F., enter the feathers, while raising the temperature in about fifteen minutes to near the boiling point; then dye to shade, lift, rinse and dry.
It is advisable, in order to obtain a level dye, to add not the whole amount of dyestuff solution required at one time, but at least in two times; which rule altogether applies to all aniline dyestuffs, more or less, as they mostly run up very rapidly and are apt, therefore, to give uneven dyes.
If a yellowish tint is wanted, use a little azo yellow or azo orange; picric acid, which was formerly very freely used for this purpose, has been almost entirely abandoned.