orpiment

Discover the secrets of pararealgar in Rembrandt’s The Night Watch. Explore its history, chemistry, and applications for artists today.

Orpiment is a rich lemon or canary yellow with fair covering power and good chemical stability as a pigment. It is designated as brilliant yellow in Munsell notation 4.4Y 8.7/8.9. It is an arsenic sulfide mineral that occurs naturally in small deposits as a product of hydrothermal veins, hot spring deposits, and volcanic sublimation, although nowadays, it can be easily obtained artificially. The arsenic content makes it toxic, although it was also used in medicine, cosmetics, and as a biocide in ancient times.