colorfastness

Colorfastness is the ability of a material’s color to resist fading or transfer under expected use conditions. It is most commonly discussed in textiles, but also applies to paints, plastics, inks, and leather. A colorfast fabric or material maintains its hue when subjected to common stresses such as washing, light exposure, rubbing (crocking), perspiration, and various chemical environments. The level of colorfastness depends on dye chemistry, the strength of the dye-fiber bond, finishing treatments, and the physical and chemical properties of the substrate.

Testing and standards

Colorfastness is typically assessed using standardized test methods. In textiles, common tests include washing fastness (ISO 105-C01, AATCC 61), light fastness (ISO 105-B02, AATCC 16), rubbing or crocking fastness (AATCC 8, ISO 11640), and perspiration or water exposure tests (AATCC 15, ISO 105-E04). Results are reported on gray scales that measure changes in color (color change) and the amount of staining transferred to or from the sample. Ratings are usually on ordinal scales (for example, 1 to 5 or 1 to 8), with higher values indicating better colorfastness.

Factors and improvement

Colorfastness depends on dye type (for example, reactive, disperse, vat, or acid dyes), fiber or substrate chemistry, fixation or mordanting, and finishing processes. Strategies to improve colorfastness include selecting more durable dye–fiber combinations, using fixation agents, applying protective finishes, and incorporating stabilizers or UV absorbers for light exposure.

Applications and limitations

Colorfastness is a key quality and performance criterion in textiles, as well as in coatings, plastics, and inks. It is inherently condition-dependent; accelerated tests approximate long-term behavior but may not capture all real-world factors.