The ISO 8781-1-1990 standard describes a method for evaluating the dispersion properties of coloured pigments by measuring the change in colour-strength of pigments. This part of the method involves preparing a series of coloured pigment dispersions, measuring their colour-strength, and calculating the rate of change in tinting strength at different stages. The standard aims to help determine the dispersion capacity of pigments in practical applications, particularly their chromadizing effect in Coating and Miscellaneous products, thereby evaluating their dispersion properties and application performance.