"Tempera isn't hard. It's just slow."I've been playing a bit more with egg tempera lately, and remembering why I like it so much. I can understand why tempera went largely out of fashion in the 16th century: oil paint has a greater value range (because oil darks are darker than tempera darks), so much can be done with blending in oil, and oil paint is perhaps more resistant to damage (although tempera doesn't crack and yellow as oil does).
Tempera, however, has its own properties to recommend it.
- Many colors have more chroma and delicacy in tempera than in oil. Ultramarine blue, for example, is lighter and more saturated in tempera than in oil—it's like a different color. Earth pigments have a clarity and vibrancy that they do not have in oil. And earths that are barely distinguishable from each other in oil paint have very distinctive characters in tempera. Siennas, red ochres, yellow ochres, golden ochres, green umbers, red umbers, burnt siennas, hematites, malachites, and so many other earths have properties that cannot be fully explored in oil paint, but which really come into their own when tempered with egg yolk.
- In tempera, pigments do not loose as much chroma when mixed with white or black as they do in oil. Tints are less chalky and shades are less dull. In tempera, you can work with higher chroma without looking garish the way really intense oil paints do. That helps to compensate for the reduced value range and gives tempera paintings a sense of delicacy and refinement without dullness.
- In oil paint, you can glaze, scumble, and partially mix multiple colors to achieve interesting optical mixtures. In tempera, the closest you can come to that is the petit lac technique common in Greek and Russian icon painting: you put a wet puddle on a panel that is horizontal and use the brush to very gently spread the paint without breaking the surface tension. That results in interesting, slightly mottled surface effects. In tempera, you can also use layer after layer of crosshatching, weaving colors across and over each other, to produce subtle optical effects.
If you have an interest in egg tempera, I can't recommend "The Practice of Tempera Painting" by Daniel V. Thompson highly enough. It covers the preparation of supports and grounds, choosing and working with pigments, doing underdrawings, application of paint, and gilding. I would only note that (a) you don't really have to grind modern pigments with a muller and slab; you can just put them in a jar with water and shake; (b) his list of pigments is a little dated; and (c) we now know that Italian tempera painters did not use a detailed underdrawing as a critical component of the development of a painting's value scale. Other than those details, the information in the book is as useful today as it was when the second edition was published in 1962.