colorfast

Colorfast is a term used to describe the resistance of a colorant (dye or pigment) to fade, bleed, or transfer under conditions such as light exposure, washing, rubbing, or chemical contact. It is a central quality attribute for textiles, printed fabrics, paints, and plastics.

In textiles, colorfastness typically refers to several specific properties: resistance to light (colorfastness to light), washing, crocking (rubbing against another surface), and perspiration. The degree of colorfastness depends on the dye chemistry and how well the dye is bound to the fiber.

Factors influencing colorfastness include the dye type and bonding mechanism (covalent or ionic attachments), fiber type (natural versus synthetic), presence of mordants or fixatives, fiber finishing, detergent pH and temperature, and UV exposure. Durable colorfastness is often achieved by selecting suitable reactive or disperse dyes, proper pretreatment, and post-treatment finishing.

Testing and standards: Colorfastness is assessed using standardized tests defined by organizations such as the International Organization for Standardization (ISO) and the American Association of Textile Chemists and Colorists (AATCC). Examples include ISO 105-B02 for colorfastness to light, ISO 105-C06 for washing, and ISO 105-X12 or AATCC 8 for crocking, as well as tests for perspiration.

Care and use: Consumers can extend colorfastness by following garment care labels, washing separately or inside out, using mild detergents, avoiding high heat and prolonged sun exposure, and storing fabrics away from direct light or UV sources. The concept also guides dye and pigment manufacturers in producing durable colors.