This part of ISO 8130 specifies a method for the determination of the equivalent-sphere particle size distribution of coating powders by laser diffraction, for particles of the size range from 1 µm to 300 µm. NOTE – Particle sizes > 300 µm may well require the use of a different optical model. This document is specific for the measurement of coating powders and also engages ISO 13320, which provides guidance on instrument qualification and particle size distribution. Laser diffraction is not suitable for determining oversize material, which can be verified by sieve analysis as specified in ISO 8130-1 or by dynamic image analysis as specified in ISO 13322-2