Karin,
Thanks for sharing your underpainting technique, especially since I'm going to start an underpainting within the hour.
The people at the ART RENEWAL CENTER were kind enough to post a little three image demo of mine that starts with an underpainting.
http://www.artrenewal.org/articles/2...painting1.html
Raw umber is my favorite color, but since I've discovered Gamblin's Asphaltum substitute, my faithfulness has been sorely tried.
Doing an underpainting is a wonderful way to solve design and drawing problems, as you say.
Bill