This is the exercise painting described in the previous post overpainted with color. Our main teaching point was to evaluate the color of the raw egg yolk. In our mind, an egg yolk is bright yellow. Yet, when we compared the yellow of our tubes to the yolk, we discovered that the color intensity of the tube yellow was always too bright. Therefore we adjusted the intensity of the yolk yellow using a tiny amount of alizarin crimson and ultramarine blue (red and blue make a purple which is the mixing complement of yellow, so it will grey down the yellow.) Since the yolk is very yellow, it takes only minute amounts of the alizarin and ultramarine to adjust it. Other things that were valuable to paint were the transparency of the raw egg white, and the colors in the white shell.
The colors used in my example of this exercise were: cad yellow light and deep, alizarin crimson, ultramarine blue, white and the underpainted asphaltum (which was still wet but thin).
Stuck for a subject? We think a raw egg is one to revisit.