3.1 Zinc oxide functions as both a chemical and a pigment. It is used in a variety of applications including rubber, paint, reprography, glass, chemicals, etc. In paint, it contributes to mildew protection, ultraviolet absorption, hiding power, and neutralization of acids formed upon oxidation of the paint film.

This specification establishes the properties and requirements for the pigment commercially known as "zinc white" or zinc oxide, which may be purchased either in the dry or paste in oil forms. Dry pigments, which may be processed either by the French process or American process, shall conform individually to required compositions of zinc oxide, total sulfur, moisture and other volatile matter, total impurities (including moisture and other volatile matter), and coarse particles (total residue retained on a No. 325 sieve). Conversely, pigments in the paste in oil form shall adhere to required composition of the pigment, linseed oil, moisture and other volatile matter, and coarse particles and skins (total residue retained on a No. 325 sieve). Pigments shall also be tested for tinting strength, and oil absorption by Gardner-Coleman and spatula rub-out methods.