Tempera

About

Egg tempera mixes ground pigment with egg yolk and a little water. It dries within minutes to a tough, satiny film, so painters build form from many small hatched strokes rather than blending. In medieval Italy and the Byzantine world it was the standard medium for panels and icons, laid over white gesso and often set beside gold leaf. Duccio's Maestà (1308–11) and Andrei Rublev's Trinity (1410s or 1420s) are both painted in tempera.

Around 1400 Cennino Cennini described the whole process, from preparing panels to applying gold, in his handbook for painters. Fra Angelico and Sandro Botticelli still used egg in the 15th century, while oil gradually took over. Revivals followed in the 20th century: Andrew Wyeth painted Christina's World (1948) in tempera, and Ben Shahn valued its clarity. Look for fine parallel strokes, a matt, even surface and colours that have not yellowed.