What about Technique?

The Panel:
A firm non flexible ground is necessary for painting with egg tempera.  On good linen canvas, the oil medium can sustain flexing and shrinking, but egg tempera cannot.  If one chooses to work exclusively in oil, canvas may be the ground of choice.  As I prefer to use a mixed technique, painting on panel is my preference.  Also, I find the smoothness of the surface very sensuous.

Of the choices readily and economically available to painters these days, I prefer thick, plywood panels.  They are heavier than Masonite but in the long run, more absorbent.  They do not warp, and the fine crackles that can occur in the gesso can be avoided by gluing a thin layer of fine inen fabric to the board before the first coat of gesso.  (The crackles are not really a factor if you intend a full oil painting over the underpainting.)

The Gesso Ground:
Various recipes exist for gesso.  Here is what I use (from Mayer).  Dissolve 2 3/4 ounces of rabbit-skin glue with one quart water in a pot or can. (This equates to 75 grams to approximately one liter of water.)  Let it soak overnight.  Heat it in a double boiler, that is, in second pan surrounding the first one with water.  The glue should never boil, only melt.  Stir regularly.

The Filler:
Use precipitated chalk or whiting mixed with 10% titanium white for the gesso filler.  The whiting can be found in any hardware store.  Dry pigments can be found at art supply shops or online suppliers like Kraemer Pigmente.  The proportions are 1 lb filler (or 450 grams) to one quart (liter) of glue water.  The melted glue is gently puoured into the chalk stirring all the while.  Lumps should be stirred or strained out.  The final result should be about the consistency of light cream.  Return the mixture to the double boiler, to keep it warm. 
 
Applying the Gesso:
Sand the panel lightly to remove any rough texture.  Cover the board with a light coating of size (1 1/2 oz rabbit skin glue dissolved in one quart water or 45 grams to one liter).  After the size has dried, begin applying thin coats of gesso.  I prefer to apply them to both sides of the panel to avoid the uneven absorption of moisture that can cause warping. Use a wide flat bristle brush, applying thin layers in alternating horizontal and vertical layers.  The layers dry quickly, especially in warm weather.  Generally a well prepared panel can take up to 20 thin coats of Gesso.  Best practice is to sand it down between each layer.  The final sanding down (after 20 coats), moves from coarse to fine.  As a last step, it is possible to take a slightly damp cloth and rub it gently over the entire surface in circular motions in order  to obtain a final absorbent, smooth, egg shell-like finish.

Egg tempera
Some basics on painting with eggs.

Mixed technique
from the Ecole des Beaux Art, Paris.

Fresco
Some basics of painting fresco and fresco secco.

Encaustic
Some new expereince with an old technique.