Definitions for "Colorfastness"
The ability of thread to retain its color during normal wear, laundering and exposure to sunlight. A dye may be colorfast when exposed to one agent, but less so when exposed to another. Polyester and nylon threads generally exhibit the best colorfastness; vat-dyed cotton threads have reasonable colorfastness. Thread used for contrast stitching should possess an "AA" colorfastness rating.
The ability of a carpet or fiber to retain color when exposed to (1) ultraviolet light, (2) crocking (wet or dry), or (3) atmospheric conditions (according to manufacturers' and government test standards).
The ability of a pressure sensitive label to retain its true color under normal conditions and/or to resist change in color when exposed to light, heat, or other influences.