High shear mixes of carbon black and many other pigments in a cellulose acetate butyrate paint chip formulation have provided superior specimens for analysis by automated electron microscope image analysis. Specimens prepared from these mixes exhibit reduced aggregation and improved dispersion. Testing accuracy, precision, and sampling are significantly improved in comparison to previous techniques. The CAB method is applicable to carbon blacks, silica, precipitated calcium carbonate, red iron oxide, titanium dioxide, and any rubber grade pigment that is composed of stable particles that are reasonably isotropic in nature. Certain ground pigments or those containing highly anisotropic particles may give erroneous results due to breakage (e.g., clay, acicular zinc oxide). An improved particle size analysis program for automated electron microscope image analysis was developed. This utilizes a self-determining factor to correct for particle aggregation. The method provided good grade classification for a broad range of carbon blacks in CAB and is also suitable for screening blacks in the dry state or extracted from rubber.