The GOST 12921-1980 standard is the Russian method standard for the determination of paper and Cardboard gloss. The standard specifies the steps and conditions for the measurement of paper and Cardboard gloss in detail, and is applicable to most types of paper and Cardboard, but does not include photographic paper and Cardboard with a gloss index of less than 5%. Through this standard, the gloss of paper and Cardboard can be accurately evaluated, which is of great significance for product quality control and comparison.