ASTM D 4302
Standard Specification for Artists' Oil, Resin-Oil and Alkyd Paints

This specification describes the conditions under which the colorants used in these types of paints should be tested for lightfastness. Since the colorants must be mixed with a standard white paint as described in ASTM D 4303, it is the colorant itself that is being tested; brands of paint are not tested. The lightfastness rating of the colorants in the oil, resin-oil, or alkyd vehicle is reported.

This specification also describes the labeling, composition, physical properties, and performance requirements for these types of artists' paints.

Within the standard a table is published that lists all the colorants that have been subjected to the tests, their Colour Index Names and Numbers, their chemical names, and their common names, terms familiar to most artists.

Lightfastness

Natural Pigments lists the lightfastness rating established by the ASTM standard for each artists' oil color where the data is available:

Colors falling in the lightfastness III category are considered sufficiently lightfast only if they are used full strength (not tinted with white) and are provided with extra protection from ultraviolet light (such as protecting with a UV-absorbent varnish).