Lead Pigments

Litharge is a heavy yellow powder frequently containing metallic lead and dirt. It is prepared by heating metallic lead or the dross from molten lead in an oven, through which is passed a current of air.

Its value as a pigment is restricted, for unless used in proper combination with other pigments, its action on the oil may be so great as to shorten the life of the paint.

Red Lead is formed by the continued heating of litharge in the air at 575°-750° F. Its quality depends on the care and skill employed in its manufacture; much of the commercial article contains metallic lead, vitrified particles, and excessive amounts of litharge.

Red lead contains more oxygen than does litharge,  but  for  chemical  reasons its action