This specification specifies the composition, physical properties, performance and labelling requirements of watercolor pigments for artists. Includes light fastness testing, exposure testing and calculation of average color difference to ensure the color Stability and conformity of pigments in actual use. The specification applies to evaluating the light fastness of pigments and provides pigment references that meet the requirements. This standard provides a mass assurance base for producers and users to ensure the Reliability of products in artistic creation. In practical applications, additional testing and verification may be required on a case-by-case basis to ensure that the performance of pigments meets the needs of use.