Oooohhhh - I am so done with this. I believe I painted the second face 4 times before I was satisfied. Finally, finally, finally I think I have a good likeness. In this photograph, the values appear different in the two faces because the paint is wet on one and dry on the other. Once the painting dries competely, I generally buff the surface with a thin coat of Winsor and Newton Liquin. It brings out the depths of the darks beautifully and dries to a low sheen finish. I will try to to remember to take another photo when I do that. This painting is 14x18 oil on linen board - my favorite support.
Here is the close up of the second portrait. I must admit, this project exhausted me!