Dyeing is normally done in a special solution containing dyes and particular chemical material. Dye molecules are fixed to the fiber by absorption, diffusion, or bonding with temperature and time being key controlling factors. The bond between dye molecule and fiber may be strong or weak, depending on the dye used. Dyeing and printing are different applications; in printing color is applied to a localized area with desired patterns and in dyeing it is applied to the entire textile.

The primary source of dye, historically, has been nature, with the dyes being extracted from animals or plants. Since the mid-19th century, however, humans have produced artificial dyes to achieve a broader range of colors and to render the dyes more stable to washing and general use. Different classes of dyes are used for different types of fiber and at different stages of the textile production process, from loose fibers through yarn and cloth to complete garments.

Acrylic fibers are dyed with basic dyes, while nylon and protein fibers such as wool and silk are dyed with acid dyes, and polyester yarn is dyed with disperse dyes. Cotton is dyed with a range of dye types, including vat dyes, and modern synthetic reactive and direct dyes.

Selection of the appropriate dye is important because any given dye is not applicable on every type of fiber. Furthermore, resistance to washing, rubbing and light differ among dyes. The choice of dye depends on the objective in dyeing and which material is to be dyed. For example, indigo dyes have poor wash and rubbing fastness on denim (cotton), so they are used to produce washed-down effects on that fabric. In contrast, vat or reactive dyes are applied on cottons to achieve excellent washing fastness.