Class A. Class A or extra fine lining aluminum pigment (powder and paste) is the finest of the three classes in particle size. It is used on air-planes, railroad coaches, motor vehicles, for sign painting and decorating, and where a very smooth finish is necessary or where it is desired to reduce the amount of aluminum used.

Class B. Class B or standard lining aluminum pigment (powder and paste) is slightly coarser than class A in particle size. It is the class most widely used, especially on bridges, storage tanks, and general construction work.

Class C. Class C or standard fineness aluminum pigment (powder and paste) is slightly coarser than class B in particle size. It is also used as a finish coat on structural metal and for similar purposes.