This article discusses the discovery of phosphorescent lithopone on watercolor drawings by American artist John La Farge dated between 1890 and 1905 and the history of lithopone in the pigment industry in the late 19th and early 20th centuries. Despite having many desirable qualities for use in white watercolor or oil paints, the development of lithopone as an artists’ pigment was hampered by its tendency to darken in sunlight. Its availability to, and adoption by, artists remain unclear, as colormen's trade catalogs were generally not explicit in describing white pigments as containing lithopone. Further, lithopone may be mistaken for lead white during visual examination and its short-lived phosphorescence can be easily missed by the uninformed observer. Phosphorescent lithopone has been documented on only one other work-to-date: a watercolor by Van Gogh. In addition to the history of lithopone's manufacture, the article details the mechanism for its phosphorescence and its identification aided by Raman spectroscopy and spectrofluorimetry.

Faber argued there hasn't been enough change in these federal regulations in the decades following the FDA's approval of titanium dioxide – especially as others increasingly point to potential health consequences.

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.

To be added to food, this additive must achieve 99% purity. However, this leaves room for small amounts of potential contaminants like lead, arsenic, or mercury (1Trusted Source).

The CaCO3 and TiO2 factory plays a crucial role in producing these materials on a large scale to meet the growing demand from various industries. The factory utilizes advanced technology and processes to extract and refine CaCO3 and TiO2 from natural resources such as limestone and mineral sands. The production process involves crushing, grinding, and chemical treatment to obtain the desired properties of CaCO3 and TiO2.

The principal natural source of titanium dioxide is mined ilmenite ore, which contains 45-60 percent TiO₂. From this, or an enriched derivative (known as titanium slag), pure TiO₂ can be produced using the sulphate or chloride process.