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.