GB/T 23981.2-2023 "Paints and varnishes — Determination of hiding power — Part 2: Black-and-white checkerboard method" is applicable to the determination of the hiding power of paints, specifying two test methods: brush application and spray application. A 200 mm × 100 mm black-and-white checkerboard is used, with the white square reflectance value of 80 ± 2 and the black square reflectance value ≤ 3. The test environment is controlled at 10–30°C with a relative humidity ≤ 80%. For the brush application method, the mass of the sample before and after application must be weighed to calculate the paint consumption per unit area; for the spray application method, the result is calculated based on the weight gain of the substrate. Observation is conducted at a 30° angle inside a dark box until the black-and-white squares disappear. The difference between parallel tests should not exceed 5% of the average value, and the calculation and reporting of results are clearly specified.