This standard specifies specific test methods for evaluating the anti-fog performance of plastic films. The core approach involves simulating a high-humidity environment (typically maintained using a constant temperature and humidity test chamber with a circulating water pump) to form water vapor on the film surface, and then assessing its anti-fog grade based on the shape, size, and distribution of water droplets or water films on the surface. The standard details the required equipment for the tests, such as high-low temperature humidity chambers and vacuum drying ovens, as well as two specific evaluation methods: visual assessment and light transmittance measurement. Additionally, for agricultural films with higher optical performance requirements, objective quantitative measurements can be conducted using a light transmittance/haze tester.