What is this standard about?
This document specifies a general method of test for comparing the lightening (reducing) power of a white pigment with the lightening power of an agreed sample of the same type.
Two procedures (A and B) are specified. Procedure A is quicker than procedure B and is suitable for testing one sample of pigment; procedure B is better for testing several samples, and especially if a pigment of unknown lightening power is being tested.