Structure-Optical Properties Relationships in Cobalt-Based Purple Pigments Used by Robert Delaunay.

Following the industrial revolution and the modernization of chemistry, purple became one of the most popular colors in the palettes of late 19th- to 20th-century painters. Among them, Robert Delaunay (1885-1941) was one of the key artists of the avant-garde movement in France in the early 20th century. Although widely used in modern and contemporary paintings, inorganic purple pigments of the cobalt phosphate and cobalt arsenate families have been little studied chemically until now.