Sulfur dye

Sulfur dyes are the biggest volume molecules which is the basis of their good wash-fastness. These dyes produce robust dyeings that have all round fastness except to chlorine. Due to the high polluting nature of the let out dye-baths, slowly sulfur dyes are being phased out. Sulfur dyes are primarily used for dark colors such as blacks, browns, and dark blues. The deep indigo blues of denim blue jeans are a product of sulfur dyes.