Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

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When examining a lithopone pigment pricelist, one might notice that prices can vary significantly between different grades of lithopone. Generally, there are two main types Lithopone 28 and Lithopone 60, with the numbers denoting the percentage of zinc sulfide content. Lithopone 28, with a lower zinc sulfide content, is often more affordable compared to Lithopone 60, which offers superior whiteness and opacity. The choice between these grades depends largely on the specific requirements of the end application.