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What is Egg Tempera?
Egg tempera paint consists of three ingredients: pigment, egg yolk and water. Powdered pigments are dispersed in water to form a paste, and then mixed with yolk. The egg oil and proteins in the yolk cure and bind the pigments to a surface. The surface most often used is a wood-based panel coated with traditional gesso (collagen glue and chalk or gypsum) sanded to a smooth finish.
All paints start with color, or powdered pigments. Pigments may be made in a lab or nature, be organic (carbon-based) or inorganic (mineral-based), date from prehistoric times or the present. They include low-chroma ochers, siennas and umbers dug from the earth; celestial blues ground from lapis and azurite; smoky blacks made from burnt bones and ivory; bright, modern colors derived from petrochemicals; and many other hues. Each pigment has a unique story and set of characteristics. Working directly with pure pigments is one of the pleasures of egg tempera.
All paints require a binder (such as a drying oil, gum arabic, acrylic polymer, etc.) to adhere pigments to one another and the surface to which they are applied. When the binder is egg yolk, its considered an egg tempered paint, or egg tempera for short. Egg tempera is made from scratch because it would putrefy if put in a tube.1 It is generally applied in diluted, very thin, often transparent layers. It is thinned with water because egg yolk is water-soluble. The paint dries to the touch within seconds (as soon as the water content evaporates) but for a painting to fully cure (polymerize) takes several months. Many layers are needed to develop an image. Tempera is commonly applied with crosshatching but also can be sponged, splattered, puddled, and manipulated in countless ways to produce both ancient and modern affects. The accumulation of dozens of layers of transparent to semi-opaque colors upon a white gesso ground is rich and luminous.
Egg tempera requires old-fashioned craftsmanship (panels and paint are made from scratch) and the painting technique, while in moments spontaneous, is more often gradual and deliberate. When egg tempera is compared to oil paints there are notable differences. Thick layers of tempera would crack, so it is not suitable for impasto painting. Egg tempera lifts if immediately reworked, so physical blending (pushing the paint around) is not possible; instead, optical blending is achieved through the accumulation of many, many layers. Tempera's quick drying time gives the paint a more linear, less painterly quality. Some artists are deterred by these attributes of egg tempera, but for others these qualities are what make it an ideal medium.
To the few who have heard of egg tempera it is most commonly associated with iconography or Andrew Wyeth (tempera's most renown, contemporary practitioner). Consequently, the medium is sometimes perceived as incapable of anything beyond the lovely, stylized look of an icon or the beautiful weave of earth tones in a Wyeth. In fact, tempera paint offers a broad range of artistic possibilities. One of my interests is to counter the misconceptions that limit egg tempera and share what I believe is its generally underappreciated potential.
My Working Method
Most egg tempera instructors teach one of two, old-fashioned techniques: the Italian Renaissance method or the icon painting tradition. Each is a systematic, logical way to work that produces excellent results. However they are not the only ways to paint in tempera. Egg tempera dates back to antiquity, but how I work with the medium does not.
I begin with a carefully considered drawing to arrange values, colors, shapes, lines, etc., into a strong image. When the design is complete I use homemade transfer paper to place the outlines of the image on a gesso panel. I then dive into the painting. I use thick and thin paint, glazes and scumbles, fine round and wide flat brushes, sponges, splatters, stencils, rubber stamps, fingers, and more. I often work with masks, and I restate the drawing as needed. I don't apply these techniques in a premeditated order, but instead use whichever is called for in a given moment to achieve the visual aims outlined in my design. It is a less systematic approach than traditional tempera techniques; a more improvisational way to work that suits my nature and goals.
1 Commercially produced egg tempera paints, sold in tubes, are not pure egg tempera. Tubed "egg tempera" is actually "tempera grassa", an emulsion of egg yolk and a drying oil (generally with other additives such as preservatives and stabilizers). Tempera grassa has some of the working properties of egg tempera and oil paints. It is a perfectly viable medium—however it is not the same as pure, homemade egg tempera and behaves differently.