ISO 8781:1990

Description

Relates to coloured pigments which have been dispersed by one of the methods described in ISO 8780. The method is of general use for comparing similar pigments, for example a test pigment against an agreed reference pigment. The principle consists in dispersing the pigment in stages under specified conditions in an agreed binder system. After each dispersion stage, a portion of the mill base is taken and mixed separately with a white pigment to form a reduced paste. The tinting strength of each reduced paste is determined as described in ISO 787-24. The percentage increase in tinting strength between two dispersion stages is calculated in order to assess the ease of dispersibility of the pigment.