1. The process for preparing from solution, lithoponeof various grades and a soluble commercial byproduct preferably of sodium, which consists in preparing separate solutions of zinc sulfate and barium'sulfid, which solutions are mixed with each other and with that of a third salt adapted to enter into combination with a freed acid group from the firstnamed salts, the same being brought together in equivalent and calculated amounts to produce and precipitate lithopone of the desired percentage, and leave in solution the soluble by-product, substantially as described.