ABSTRACT
Abstract: Direct dyes are water soluble and anionic in nature; these dyes retain sulphonic acid groups in structure. Though light fastness is seemingly good for most of the dyes, wash fastness suffer because of their water solubility. Most of the dyes belong to azo class and are invariably applied on cellulosic fibres, where the product faces no domestic washes, like cheaper carpets. Dyes are retained by the fibre through H-bonds and Van der Waals force. Wash fastness may be improved by suitable after-treatment of dyeings. Due to presence of acid groups, direct dyes react with protein fibres forming wash fast shades but lack brilliancy.
