Society of Tempera Painters
"Egg tempera is a painting process that uses egg yolk to bind pigments. The artist must manufacture the paints him/herself by the simple process of mixing finely ground pigment, water and dilute egg yolk."
Although tempera has been out of favor since the Late Renaissance and Baroque eras, it has been periodically rediscovered by later artists. The 20th century saw a significant revival of tempera including artists Giorgio de Chirico, Otto Dix, Eliot Hodgkin and Andrew Wyeth.