The ISO 8781-3:1990 standard specifies a method for assessing the dispersion characteristics of pigments by Gloss variation. The core of this part is to evaluate the Glossiness achieved by pigments during the coating drying process to judge the dispersion of pigments. Specific methods include stage-preparation pigment dispersion, measurement of Glossiness of Dry-Film, and analysis of the rate of development of Glossiness. The standard is designed to help compare the dispersion characteristics of different pigments to determine their performance in the final application. This standard applies to quality control and performance evaluation of pigment production and Coating formulation design.