The additives that received a “no safety concern” conclusion based on current estimated dietary exposure are as follows:
In order to evaluate the penetration of the nanoparticles, eight adult male Wistar rats (3 months old) were used for the in vivo experiments. The protocol was approved by the local University Committee for animal testing and is in accordance with the Canadian Council on Animal Care (CICUAL-RD-2021–892-E-UNC-DEC#FCQ).
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.
To overcome this challenge, manufacturers use advanced technology and processes to monitor and control the buff percentage of their products. This may involve the use of sophisticated equipment to measure the coating thickness of titanium dioxide particles, as well as automated systems to adjust the level of coating as needed. By carefully controlling the buff percentage, manufacturers can ensure that their products meet the specifications of their customers and maintain a high level of quality and performance.