detailed pigment histories, recipes...
Pigments are the basis of all paints, and have been used for millennia. They are ground colored material. Early pigments were simply as ground earth or clay, and were made into paint with spit or fat. Modern pigments are often sophisticated masterpieces of chemical engineering.
via webexhibits.org
"Artists use the technique of “equiluminance” to blur outlines and suggest motion. We cannot perceive the edges of objects where object and background have the same luminance. If parts of a painting are equiluminant, their positions become ambiguous. They may seem to shift position or to float."
