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.

The authority did not identify a safe amount of titanium dioxide that could be consumed.

Overall, the Food Directorate's comprehensive review of the available science of TiO₂ as a food additive showed:

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Opportunities

The precipitation of titanium dioxide involves the reaction of titanium sulfate with an alkaline solution to form titanium hydroxide, which is then calcined to produce titanium dioxide. The precipitation process is crucial for achieving the desired particle size distribution, crystallinity, and purity of the final product.