GB/T 46184-2025 "Paper and Board - Test for Colour Fastness Assessment" applies to the evaluation of colour fastness of paper and board dyed with dyes and printed with dye-based inks, and is not applicable to products printed with pigment-based inks. It is modified and adapted from relevant international standards to suit China's technical conditions. The standard specifies test methods for the colour removal properties of paper and board, covering core aspects such as sample preparation, test conditions, operational procedures, and result determination. It clarifies technical requirements, including the purity of chemicals and the use of distilled water for testing. The formula for calculating the colour removal index has been adjusted, with added explanations on the relationship between colour fastness and the colour removal index. Relevant testing instruments and environmental conditions are also standardized.