Direct Fast Dyes

These are soluble in water and have direct affinity for all cellulose fibers. Some will also dye silk and wool. By continuous research this group of dyes has been supplemented with dyes of good fastness to light and washing. As these dyes, when dyed without additives, do not exhaust well, an addition of salt is required to improve the yield of the dye and obtain deeper shades. Generally, the wash fastness of these dyes is inferior but there are a number of after treatments available to improve the wash fastness of the dyeing. Most direct dyes can be stripped of the use of stripping salts (Sodium Hydrosulphite) without harmful effects on the fibers.

USE: Direct dyes dye all cellulosic fibers, including viscose rayon, and most of them also dye wool and silk. They do not dye acetate rayon and synthetic fibers. Direct dyes can be applied well at how temperatures and are therefore suitable for tie-dyeing and batik work. Generally these dyes are used where high wash fastness is not required.