Acid dyes are water-soluble anionic dyes, containing one or
more sulfonic acid substituent or other acidic groups. Acid dyes are applied from acidic dye baths to nylon, silk, wool, and
modified acrylics. They are also used to some extent for paper, leather,
ink-jet printing, food, and cosmetics.
Definition
The sodium salts of organic
acids used in the dyeing of silks and wool.
They are so called because they are applied
from a bath acidified with dilute sulfuric or
ethanoic acid.