Term: Permanence

Permanence is an indication of the length of time a pigment will retain its original color. Ideally, pigments used in paints will be lightfast and will not react chemically with the atmosphere or other pigments and materials used in painting.

Most paint manufacturers indicate the permanency of the pigments they use on the paint labels they print. For example, the American Society for Testing and Materials (ASTM) rates lightfastness of pigments from I - V: ASTM I = excellent; ASTM II = very good; ASTM III = may be satisfactory if applied full strength. In this system both I and II are considered permanent for artists' use.

See also Fugitive Color