Sulfur dyes are the most commonly used dyes manufactured for cotton in terms of volume. They are cheap, generally have good wash-fastness, and are easy to apply. 

ulfur dyes are water-insoluble. In the presence of a reducing agent and at alkali pH's at elevated temperature of around 80 °C, the dye particles disintegrate, which then becomes water-soluble and hence can be absorbed by the fabric.