A water based paint whose color is mixed with egg yolk?

Egg tempera is a terrific medium with many advantages. It is safe, non-toxic, and permanent. Unlike oil paint, it will not yellow, change in color, or grow transparent over time. Unlike acrylic, it has a proven track record going back hundreds of years. Egg tempera shows the beauty of pigments off to great advantage. Colors are clear, bright, and pure. This is a terrific site that explains what-why-and how to make your own: * http://www.alessandrakelley.com/eggmedium.html