The specified method is most likely to be indicative of the comparative results which will be obtained when the materials being compared are ground in a resin solution in a ball mill. Portions of the test sample and the agreed sample are each milled with the chosen medium under specified conditions on a paint conditioning machine at the same time, measuring the degree of dispersion of each sample on a fineness-of-grind gauge at known time interyvals during the dispersion process. Construction of the corresponding graphs from these results. The times for each material to reach a stated fineness-of-grind are taken as indicative of the comparative ease of dispersion.