Nowhere
else is there a class of dyes which
delivers so much color for your money,
with products whose chemical structures
are, in almost all cases, unknown. Nowhere
is there a class of dyes with such
good fastness to washing, coupled with
such sensitivity to treatment with chlorine.
Some are notorious for a characteristic
mercaptan odor during dyeing, but no one
selling other dyes for cellulosic fibers
regards them as anything but serious
competition. There is no black on cellulose
which can compare with the attractive
shade and depth possible with (2.1. Sulfur
Black 1, which accounts for it being one of
the most widely used dyes in the world.