ISO 787-8:2000 "General test methods for pigments and fillers, Part 8: Determination of substances soluble in water, cold extraction method" specifies a standardized method for determining the mass percentage of substances soluble in cold water in pigments or fillers. This method extracts soluble substances from a sample by cold extraction to provide accurate determination results. This method may give different results in the testing of certain materials compared to the thermal extraction method (ISO 787-3). Therefore, the standard recommends that the test method used be clearly selected and stated in the relevant instructions to ensure the conformity and accuracy of the test results. The methods in the ISO 787 series of standards apply to a wide range of pigments and fillers, ensuring conformity and Reliability of tests.