tempera
Tempera (or poster paint) consists of inorganic pigments and an emulsion binder. The binder comprises a greasy or resinous component (linseed oil, linseed varnish, poppy seed oil, walnut oil) and a watery component (egg, glue, gum arabic, starch).
If the proportion of oil or resin is relatively high, tempera can only be used in the same way as oil paints. If the watery component outweighs the other components then the tempera can be used like gouache paints.
Tempera painting was one of the most widely used techniques right from the start. In the 15th century, oil painting from the Netherlands and then from Italy gradually supplanted tempera painting. Tempera can also be combined with oil paints to form a mixed technique. Unlike oil paints, tempera paints do not blend in easily with each other so each colour stands out starkly giving tempera paintings a rather hard impression. When dried, colours are different from when they are wet.
Since tempera dries rapidly, further layers of paint can be applied in quick succession. For this reason tempera is particularly suitable as the underpainting (base layer). The colours of wet tempera differ from those of when it is dry, when they have a matte effect. A final coat of varnish increases its luminous power thereby decreasing the visual difference from oil painting.