Sets out methods for determining the particle size distribution of particulate materials by means of centrifugal sedimentation in a liquid. The method of determining the particle size distribution described in this part of ISO 13318 is applicable to powders that can be dispersed in liquids, powders that are present in slurry form and some emulsions. Typial particle size range for analysis is from about 0.1 µm to 5 µm. The method is applicable to powders in which all chemical or physical particles have the same density and comparable shapes and do not undergo change in the suspension liquid. It is usually necessary that the particles have a density higher than that of the liquid. This Standard is identical with and has been reproduced from ISO 13318-2:2001.