Direct dyes are a class of dyes for use on cellulose fibers, such as cotton. It is one of the two types of dyes that are mixed in 'all purpose dyes' such as Rit, Tintex Hot Water dye, and Dylon Multi-purpose Dye. The colors of most direct dyes are duller than those provided by fiber reactive dyes, and the washfastness is poor: expect anything dyed with them to 'bleed' forever. One small advantage is that direct dyes are, in just a few cases, a little more lightfast, that is, resistant to fading in the light, than a few of the fiber reactive dyes. Another possible advantage is that direct dyes can be applied in the same boiling-water dyebath with acid dyes

Acid dyes are used to dye protein fibers such as wool, angora, cashmere, and silk, as well the milk protein fiber called Silk Latte, the soy protein fiber called Soy Silk, and the synthetic polyamide fiber nylon. Acid dyes sound scary to some novices, who imagine that the dyes themselves are caustic strong acids. In fact, the dyes are non-caustic, are in some cases non-toxic, and are named for the mild acid (such as vinegar) used in the dyeing process, and for the types of bonds they form to the fiber. Some of them are significantly more toxic than fiber reactive dyes, while others are even safe enough to eat, and are sold as food coloring.

These dyes are high exhaust type based on Mono-chlorotriazene and are especially suitable for exhaust dyeing method. They are characterized by excellent yield at low as well as high liquor ratio and are of special importance for cotton yarn, knits and fabrics. They are widely used for dyeing cellulosic component in the polyester - cellulosic blends.