EGG TEMPERA: A BRIEF INTRODUCTION
BY PETER DE LA FUENTE
tempera is an ancient medium. It has been found in some
Egyptian temples, and was used extensively throughout the Italian Renaissance. It
is extremely permanent, and does not darken with the ages, as oil
does. It is also highly regarded for its inherent luminosity. Peter Hurd was an early
pioneer of the medium
The process of painting in egg tempera begins with a substrate of masonite or good plywood. During the Renaissance, a wooden plank was used, which often split along the grain with time. Untempered masonite does not have a grain, and is widely used today as a substrate. After a light sanding, the surface of the masonite is ready for the gesso, which is the ground on which the tempera will be applied. It is important to use the traditional animal hide gesso described here, rather than today’s widely available “gesso”, which is really just plastic with a lot of white pigment in it. It is non-porous acrylic, and will not have the molecular bond between the gesso and egg that gives the tempera its unique permanence. The following preparation and application of traditional gesso is very important to the process of painting in egg tempera.
In past ages, animal hides were boiled for days to extract a glue sufficient to bond the whiting to the panel. Today we use rabbit-skin glue that can be procured in granular or powder form. This glue is soaked overnight in a very specific quantity of water. The glue is then heated to approximately 125 degrees. Chalk, crushed marble, and a small amount of sugar or honey is added carefully to the hot glue, stirring slowly, so as not to create bubbles in the mixture. This hot mixture is applied to the panel in a series of about eight coats, sanded in between. After the final coat has been sanded, the panel is ready for pigment and egg.
The process of painting begins each morning with a fresh egg. The yolk is separated, and mixed with a small amount of distilled water. This slightly thinned egg yolk is then mixed with pure mineral pigments. These pigments are finely ground earth colors, iron oxides, leads, cadmiums, and other very stable minerals. The egg is the binder, and is applied to the gesso panel in thin layers of color which dry in about 20 seconds. Layer upon layer of the egg yolk pigment results in the pleasing smooth, mat surface we see in an egg tempera painting. Temperas take weeks, and often months to complete. Some artists choose to use certain varnishes with varying degrees of success. Peter Hurd and Andrew Wyeth would sometimes use a beeswax varnish, but often left the luminous surface alone. After six months to a year, the tempera has cured, and will not change with time.
NOTE: A DVD PROGRAM ON THE PROCESS OF EGG TEMPERA IS IN THE WORKS, AND WILL BE AVAILABLE THROUGH OUR GALLERY