Dyeing with Sulphur Dyes

The basis of dyeing with sulphur dyes is similar to vat and indigo dyes. Sulphur dye, which has no affinity for fibre and is insoluble in water, is reduced in an alkali environment and converted into a leuco form that is soluble in water and has an affinity for fibres, and afterbeing taken up by the fibres, it is converted back to its initial water-insoluble state by oxidation. They are mostly used in dyeing cheap, ordinary materials, especially in dark and dull colours such as blue, black, navy blue, brown, olive and khaki. In this chapter, information is given about the structure and classification, fastness properties and end-uses of sulphur dyes, and then how to dye with these dyes according to both exhaustion and impregnation methods is explained in detail.