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.