GB/T 8432-1987 stipulates the relevant content of the Humidity control master standard for light fastness testers. The standard specifies the technical requirements of the Humidity control master standard, including its Humidity characteristics, Stability indicators, etc. The production materials, production process and use methods of the master standard are described in detail, which provides a reliable reference for the Humidity precise control of the light fastness tester during the test process. By using the Humidity control master standard that meets the standard, the light fastness test can be carried out in a unified and stable Humidity environment, and the accuracy and comparability of the test results can be improved.