Evolution of a face

While making my digital paintings, I will either start painting over a rough scanned sketch, or start from scratch.  If I can't get the face right, I'll turn it upside down, or put it in a monochromatic scale to reduce the distractions that my brain wants to see (which are not there).  It doesn't always work, but when it does, I'm happy.  You can see one such evolution here.  There were, of course, many steps in between each thumbnail I've shown.

Once I get the face finalized, I play with adding background detail/texture, and/or color.