The ASTM D4303 standard tests the light fastness of colorants in artist materials, simulating the color change of pigments under long-term indoor lighting. The test includes four methods of accelerated exposure using Light sources such as Xenon-arc, fluorescent lamps, etc., to evaluate the Stability of pigments. The test parameters include Light spectrum radiation exposure, Humidity, and temperature control. It is suitable for different types of coatings such as oil, Resin oil, acrylic. The standard helps producers and users understand the light Stability of pigments in actual use, ensuring the color persistence of artworks.