Painting executed with ground pigment mixed with a water-soluble material, such as egg yolk, gum, or wax.
The special ground for tempera painting is a rigid wood panel coated with thin layers of gesso, a preparation usually made of plaster of Paris and glue. Tempera paint is resistant to water and allows overpainting with more colour; the thin, transparent layers of paint produce a clear, luminous effect. The exclusive medium for panel painting in the Middle Ages and early Renaissance, it was largely superseded in the 15th century by oil paint.