This part of ISO 8780 specifies a method for the dispersion of pigments and extenders using ahigh-speed impeller mill. It is for use in conjunction with the methods of assessment described in ISO 8781, using an agreed binder system. It should be read in conjunction with ISO 8780-1. NOTE 1 A high-speed impeller mill may be used either to disperse a pigment fully or partially as a preliminary to further dispersion using other equipment, for example sand or bead mills or attritors. This method is restricted to mill bases of moderately high viscosity due to either high binder concentration and/or high pigment concentration which produces high shear forces. It is not intended to provide a means of formulating full-scale mill base compositions (scaling up the process from laboratory equipment to factory mills is not simple).