The Acid dye is too effective on protein fibers as well as on silk. The offered colorant is effective in dyeing nylonas well as synthetic fibers. This dye works as an anion and is negatively charged in a solution. Offered colorant is best suited for silk, nylon, polyamide, wool and modified acrylics. It has zero affinity to cotton cellulose. Its toxicity level varies. Devkalpi Industries offers Acid dye, which is safe to be used as an excellent food color.