The RGB LED panel was made ad hoc, and configured for solar simulation white light (including the absorption spectra of the nanoparticles: 390–410). No heat was detected at the working distance. The retina of the albino male Wistar rats were not affected under these conditions, because the intensity and time of the applied irradiation was lower than the regular fluorescent lamp bulb in the room (216.65 W/m2) [34].
Let’s break the risk down further.

Public health groups urge FDA to cancel titanium dioxide in food, by Center for Science in the Public Interest, May 30, 2023
The Asian market was favorable to the rising price trends of titanium dioxide in the first quarters of 2023. The prices inclined gradually with some slight fluctuations. The positive outlook of the market was a direct effect of removing covid restrictions, upscaling industrial production, and high speed of market recovery.
Australian researchers examined how titanium dioxide as a food additive affected gut microbiota in mice by orally administering it in drinking water. The study, published in the journal Frontiers in Nutrition in 2019, found the treatment could “alter the release of bacterial metabolites in vivo and affect the spatial distribution of commensal bacteria in vitro by promoting biofilm formation. We also found reduced expression of the colonic mucin 2 gene, a key component of the intestinal mucus layer, and increased expression of the beta defensin gene, indicating that titanium dioxide significantly impacts gut homeostasis.” The changes were then linked to colonic inflammation, along with a higher expression of inflammatory cytokines, which are signal proteins that help with regulation. The researchers concluded that titanium dioxide “impairs gut homeostasis which may in turn prime the host for disease development.”
Other experts say there is simply no conclusive evidence at this point that titanium dioxide is damaging to humans after ingesting. Kaminski in particular said the research studies cite health hazards that were found by using high doses of the product, which you would not normally see in food.

Food additive or carcinogen? The growing list of chemicals banned in EU but used in US, by Mikaela Conley, The Guardian, June 23, 2022
Lithopone, a white pigment composed of a mixture of barium sulfate and zinc sulfide, is commonly used in the leather industry as a coloring agent
. Leather suppliers around the world rely on lithopone to achieve the desired color and finish on their products.Titanium dioxide particles help light scatter and reflect, Kelly Johnson-Arbor, MD, a medical toxicology physician at the National Capital Poison Center, told Health. Because of that, we often use it as a whitening agent.
History

When used in an ultrafine-grade formulation, titanium dioxide becomes transparent to light, effectively making it an absorber of UV light. And because its particles are so small in this form, titanium dioxide creates a transparent barrier that absorbs UV light.