zinc sulfide content, %

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.

One of the primary advantages of lithopone is its excellent thermal stability. It performs well under high-temperature conditions, which is essential for paints that will be exposed to extreme weather. Lithopone’s resistance to UV radiation helps maintain the brightness and color integrity of paints, making it a preferred choice for outdoor applications. As a result, many suppliers are focusing on providing lithopone that meets the specific needs of manufacturers in the architectural, automotive, and industrial paint sectors.