The ISO 18949 standard specifies the test method for the Stability of reflection color photographs under low Humidity conditions. The standard aims to evaluate the durability of color photographs in a drying environment to ensure that they retain image mass for a long time in a low Humidity environment. The test method evaluates the color Stability, image mass and physical changes of the material by simulating low Humidity conditions. This standard is essential for manufacturers of image materials, conservators and archives to ensure the long-term preservation performance of image materials under adverse environment conditions. By applying ISO 18949, users can obtain a scientific basis for the performance of reflection color photos in a low Humidity environment, allowing for appropriate storage and protection measures.