The obliterating or hiding power of paint can be measured by determining the weight of paint needed to obliterate uniformly a card or board painted with black and white squares. This is often done by spraying a wedge to determine the point of opacity, then measuring the film thickness by comparison to unpainted substrate. A glass plate with studs forming a tapering space may be used to measure opacity of wet paint.

It should be noted that the hiding power of paint is the combined effect of the light refracting and absorbing powers of pigment and medium.

The most important factor governing hiding power is the difference between the refractive indices of the paint medium. The greater the difference, the greater the hiding power.