The preparation of egg tempera
A) Preparing the wood panel for painting
The panel must be of plywood.
*The panel surface must be very smooth.
Reinforce the back of the panel with a wood frame to avoid that the panel bends or deforms from the moisture of applied plaster.
What is “gesso”? Gesso is a mineral (calcium sulfate) composed of calcium, sulfur and oxygen.
Ingredients for preparing the white base.
Years ago, gold was used as the base of panel painting; now gesso and rabbit glue are used to form the base.
In general, several coats of gesso are applied so the panel surface becomes compact and smooth.
When the panel is perfectly dry, it is important to smooth it with sand paper until the surface resembles that of a mirror.
Rabbit glue is mixed with the plaster powder, in equal portions.
1) Prepare the rabbit glue. Allow the glue to rest in the water for about 12 hours. Heat the glue and water mixture in a water bath so that it melts well.
2) Evenly apply a coat of the glue mixture to the entire table surface.
3) Slowly add the plaster to the glue, in one session, making sure that all mixes well.
4) After the panel has completely tried, apply enough layers of the plaster-glue mixture to the table so that the panel becomes very white.
Colors are prepared by mixing powdered pigments with a bit of egg yolk and water.
C) Applying the paint
A very fine brush
is needed to avoid that any lumps of the colored pigment are applied to the panel surface. The fine size of the brush and brushstrokes means that it takes a very long time to create a painting using this technique.
The technique learned and used is that described by the great 15th
century craftsman, Cennino Cennini
in his book, “Il Libro dell’Arte”.