Acid Dyes
Acid dyes are water-soluble anionic dyes, containing one or more sulfonic acid substituents or other acidic groups.Acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dye baths. Acid dyes are not substantive to cellulosic fibers. Most synthetic food colors fall in this category.