5.1 This test method allows the user to make a determination of the blueness or yellowness of the tint undertone of titanium dioxide pigments, versus a reference pigment agreed upon by the parties to the test. This is an important measure of tone, since it gives both a measure of effective particle size, and quick approximation of the blue/yellow undertone that can be expected when a coating containing the titanium dioxide is tinted.

5.2 Such matters as the vehicle for preparing the dispersions and the mechanical method of preparing the dispersion are left to the user. However, variation in these practices will lead to increased variance in the results, so users ought to fix these parameters, in-so-far as is possible, within any one laboratory. This will lead to reduced uncertainty of the results within that laboratory, and it is seldom that interlaboratory comparisons of this test result is needed.

5.3 Each user must decide whether the loss of accuracy in his measurements due to variation of these parameters is negligibly small for the purpose for which the data are obtained.