When it comes to sourcing titanium dioxide, it is essential to understand the various processes involved in its production. The two primary production methods are the sulfate process and the chloride process. The sulfate process tends to be more cost-effective in certain contexts, but it also generates a substantial amount of waste, putting pressure on manufacturers to invest in waste treatment technologies. On the other hand, the chloride process is known for its superior quality and lower environmental impact, albeit at a higher production cost.
We even use titanium dioxide when brushing our teeth as it’s found in many toothpastes.
The author thanks Marco Leona, Scientist-in-Charge of the Department of Scientific Research at the Metropolitan Museum of Art for conducting fluorescence spectrometry on Wheel of Fortune and a valuable discussion of the research, as well as Silvia Centeno, Research Scientist at the Metropolitan Museum of Art, who performed Raman analysis on the watercolors and also contributed her insight. The phenomenon of the phosphorescing lithopone was originally discovered during the author's fellowship in the Sherman Fairchild Center for the Conservation of Works on Paper, funded by the Andrew W. Mellon Foundation. The author thanks all her colleagues for their ideas and support during the research of this paper, and special thanks to Rachel Mustalish for her assistance in editing this work.