At all times have the feathers, which are to be dyed, scoured well,
that is, washed clean from all externally adhering impurities, fat,
etc.; naturally colored feathers bleached for all light and medium
shades to be dyed upon them, and rinsed perfectly clean from the
scouring or bleaching bath, first in two or three warm waters and then
in cold water.
On taking the feathers from any bath, always squeeze the liquid out
first by drawing the feathers through the hand closed upon them, then
by placing them straight between several laps of clean dry muslin and
repeatedly passing the hand with quite a smart pressure over it. Never
transfer the feathers, in any case, from one bath to another in a wet,
but in a moist condition, or nearly dry.
Never allow the feathers to become dry in the course of operations. If
it is necessary to interrupt work, or to put feathers to one side for
further treatment, dry them properly by first passing them through a
bath of raw starch, in order to have the flues at all times as well
opened as possible.
In no case let the temperature of a bath, in which feathers are
treated, rise to actual boiling, although for some dyestuffs a
temperature near the boiling point is required to make them dye up, to
become level or to fix them.
In every instance, where an acid or acid salt is employed, either in a
separate mordanting or fixing bath, or as a component of the dyebath,
rinse well before drying.
When sulphuric acid is used in the composition of a bath, add only so
much of it as to give the water a very slight, scarcely perceptible
acid taste.
Although some artificial dyestuffs dye up without an addition of acid
to the dye bath (basic dyestuffs), the addition of sulphuric acid, in
a very small quantity, to the dye-bath is advantageous, rendering the
colors brighter and also faster.
When bisulphate of soda is employed, it is not necessary to also add
sulphuric acid to the dye-bath; if it is added, however, it must only
be in a very small quantity; careful rinsing in several warm and cold
waters after dyeing is required.
When alum alone is used without any other addition as mordant,
sulphuric acid may be added, but only in the proportion of one tenth
or, at the most, up to one fifth of the weight of alum, and careful
rinsing in several warm and cold waters is the more indispensably
required the more acid has been employed.
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.