Grades 3–5 · Arts & Music
How could egg yolk help paint stay on a picture?
Colored powder alone does not make a durable painting. Loose grains can rub away from a surface. In egg tempera, an artist combines pigment with an egg-yolk medium that helps hold the color in place.
In the diagramA binder keeps pigment particles in a paint filmwater leavespigment + binder remainprepared surface above supporting panelEnlarged paint film; pigment supplies the visible color.
Pigment supplies the color, while the medium acts as a binder. Water allows the mixture to spread in a thin layer. As that water leaves, the binder remains among the tiny pigment particles and around them.
The resulting paint film joins the particles to one another and to the prepared surface underneath. This explains why the choice of binder matters even when two paints begin with the same colored powder.
Painters have used many binding materials, including gums, oils and modern manufactured substances. Egg tempera is one historical solution. Its surviving paintings combine artistic decisions with the physical work of holding very small colored particles together.
About this explanation
Starting knowledge: Recognize pigment as a source of color and know that wet material can leave a solid coating when it dries.
Sources
- National Gallery, London — Tempera: Glossary