This part of ISO 8780 specifies a method for the dispersion of pigments and extenders using an automatic muller. It is suitable for comparing small samples in the quality control of pigments. This part of ISO 8780 is for use in conjunction with the methods of assessment described in ISO 8781, using an agreed binder system of high viscosity free from volatile solvents. It should be read in conjunction with ISO 8780-1. This method is restricted to high-viscosity mill bases. The results obtained are not for comparison with dispersibility results obtained using other methods of dispersion.