So unpretending this color appears, so difficult is it to produce,
and it requires a considerable amount of practice and good judgment
to bring out a good color from the beginning, as very little too much
or too little will spoil a color either in tone or in shade. A very
good logwood gray, which with proper attention seldom fails to turn
out satisfactory, is made as follows: Prepare a hot bath, to which add
a small quantity of decoction of logwood; enter the feathers and work
them in the bath for fifteen or twenty minutes, according to shade
desired. Then take them up, add to the bath very little pyrolignite of
iron, that is, only as much as to turn the color of the bath; re-enter
the feathers, agitate them again for fifteen or twenty minutes in the
liquid; then lift, rinse and starch as usual. This color might be
best described as dark ash gray. Instead of pyrolignite of iron, some
solution of copperas may be used. It will be easily understood, that
the more concentrated the decoction of logwood is, the darker turns out
the color, and it is in that respect particularly that the dyer has
to use good judgment in producing shades from silver gray to dark ash
gray. This color, besides, presents the advantage, that by topping it
with solutions of blue, brown, yellow or green coal-tar dyestuffs a
great variety of mode colors can be produced.