Using only egg yolk as a binder, egg tempera produces extraordinarily luminous paintings of great permanence. The simple nature of the paint film and the traditional painting surfaces allow egg tempera paintings to withstand conditions that often ruin oil paintings. Once fully dry, egg tempera ages more slowly than almost any other medium.
The Basics of Egg Tempera Painting
Egg tempera paints consist of dry, powdered pigments ground with pure water to a paste which is then tempered (altered) with egg yolk either pure or thinned slightly with water. This paint is then applied to a wood panel coated with a layer of glue (called "size" or "sizing") followed by several sanded layers of true gesso.
Some painters varnish the finished painting with an oil or resin varnish while others simply burnish (polish with cotton or a lint-free rag) the painting surface to a semi-gloss finish. The painting is then framed, traditionally without glass, and is then ready to be hung.
Preparing the Painting Surface
Traditionally, egg tempera painting surfaces were made of plies of wood with the direction of the grain of wood of each ply at right angles to the ply beneath it. The plies were glued together and allowed to dry and stabilize.
Bass, whitewood, poplar and bay "mahogany" seem to be the best woods. However, contemporary manufacturers of hardboard panels claim that their products are as good as or better than traditional wood panels. In special cases, even heavy-weight watercolor paper is used.
Whatever surface you choose should be cleaned, usually with alcohol then lightly sanded. On this surface, apply a sizing – traditionally a glue such as rabbit hide glue, although some modern technical experts recommend PVC glue instead.
Over this protective sizing, you apply a true gesso made usually from chalk (calcium carbonate) and glue size or a mixture of plaster of Paris (calcium sulfate) and glue size. Either mixture is applied in several thin layers with each layer sanded lightly when it is dry.
The Egg Tempera Painting Underpainting
Traditionally, the painting begins with a careful line drawing of the scene which is then carefully painted using transparent washes of black india ink. This underpainting makes it easier to model the image with subsequent layers of colored paints.
Choosing the Pigments for the Painting
A typical limited palette would consist of mostly opaque paints such as cadmium yellow medium, cadmium red medium, cobalt blue, chromium oxide green, ivory black and titanium white and possibly yellow ochre and burnt sienna. For crimsons or violets, add a quinacridone of that shade or the permanent alizarin crimson shade of pyrolle red. For bluer greens you could add virdian, and, for greener blues, add cerulean blue.
Normally, people used to oil painting or watercolors avoid black pigments because they produce muddy colors. This is not true in egg tempera painting. Mixtures of colors with black in egg tempera may produce cleaner darks than complementary colors do in oil painting.
Beginning the Colored Painting
To begin painting, mix about equal volumes of your pigment/water paste and your egg yolk medium. Try a little of this mixture on a glass surface. If it dries flat looking, add more medium. If it dries slowly and is glossy, add more pigment/water paste. Egg tempera paints should dry to a low-gloss finish.
Apply the tempered mixture to the surface in thin layers, usually using a sable round brush. The nature of egg tempera is that the painting surface is built up thin strokes in many layers of alternating translucent or opalescent (halfway between transparent and opaque) paint film that gradually build up the forms of the scene.
Several layers of a color such as cadmium yellow create an opaque layer of yellow. Layers of different colors produce subtle mixtures of those colors with the colors of the top layers dominating. Alternating layers of yellow and blue, for instance, will produce subtle greens although you can, of course, mix your pigment pastes to produce the green you want.
Normally you work from the background objects in the scene gradually forward to the foreground objects. Working this way, you gradually build up the painting until you achieve the image you want.
Notes on Special Characteristics of Egg Tempera Paintings
Generally, egg tempera works best to produce "blond" paintings. These are paintings that have a relatively high "key" or degree of lightness. Dark paintings work less well in egg tempera than in oil.
Also as part of the blond nature of the medium, egg temperas work best when the overall tone of the painting is relatively neutral or cool. Egg tempera does not effectively produce very warm colors. Colors in this medium tend to become hot without ever becoming warm.
However, modern painters such as Andrew Wyeth produce highly effective paintings in tones of yellows, oranges and reds. Carefully handled, the relative coolness of the medium -- despite the natural but unobtrusive yellow of the egg yolk -- allows you to work in overall warm color ranges without becoming garish.
Sources:
- The Practice of Egg Tempera Painting by Daniel V. Thompson, Jr., Dover Publications, Inc., 1962
- The Artist's Handbook of Materials and Techniques, by Ralph Mayer, Viking Press, 1982.
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