to rubbing and crocking.
Polysulfide works by improving the
stability of reduced dyebaths toward premature
oxidation. Good rinsing prior to
oxidation ensures the absence of a high
surface concentration of sulfur dye, known
as loose color. Soaping-off heavy shades
after oxidation not only removes any
oxidized surface color but also improves
the shade stability towards changes on
washing. Unlike vat dyes, there is no
recrystallization of pigmentary sulfur dye
particles within the fiber during soaping.