The ISO 8781-1 standard specifies a method for evaluating the dispersion characteristics of pigments and whitening agents, using the evaluation method by the change of color-strength of colored pigments. This method is suitable for colored pigments that have been dispersed by the ISO 8780 method. The principle is to disperse pigments in stages in a specified gluing agent system. After each dispersion stage, a part of the ground binder is taken and mixed with the white pigment to form a diluted slurry. Then, the color-strength of each diluted slurry is determined according to the method of ISO 787-24. The dispersion of pigments is evaluated by calculating the percentage change of color-strength between the two dispersion stages. This standard is widely used in pigment and whitening agent quality control and Product Research & Development.