I had a student who wanted to do egg tempera. We researched it and she mixed
her own, cheap pastels with the egg yolks. She crushed them, but we didn't
have the proper mortar and pestle which would have helped tremendously. It
made a beautiful painting, but she had trouble with it flaking off in one
area. It didn't seem to want to adhere to the canvas board there for some
reason. I think pure store-bought pigments would have done better. I suspect
the binders in the cheap pastels may have interfered with the adherence.
I would like to hear from anyone who knows what causes this problem!
To encourage you, though, the whole process was very simple. We found a web
site that was helpful, I'll send it from school if I find it. It is not
rocket science. She mixed the paints and put them into baby-food jars which I
would cart to a fridge after her class. They kept for the duration of her
painting experience. The resulting painting had a beautiful luminous quality,
and I intend to try it myself one of these days.