In college, I took a few illustration classes. I was a painting/drawing major and certainly wasn't what makes an illustrator an illustrator, but my school's drawing/painting program didn't teach many courses that actually taught you how to draw or paint (except the basics, which everyone, regardless of major, took).
My teacher, whom was quite good at his craft talked about painting shadows quite a bit in Figure Painting. FIrst off - it's the first thing you paint - our underpaintings were done using a the rub out technique - you'd basically draw only the shadows, using a large brush, or even a rag.
The next bit is where it gets interesting - once you're done with blocking in the shadows, *you never touch the shadows again*. His reasons were simple: No one ever pays attention to shadows, so don't worry about them.
There's some interesting ideas in this technique - for one - he's probably right. Secondly, shadows are supposed to retract - adding layers of paint would only make the shadows, "pop out", which isn't what you do.
I didn't take the prereq's of figure drawing, so I missed what the teacher had to say about drawing shadows, but I'd guess that painting shadows is similar to drawing them: don't take too much time in drawing the shadows - except to make sure they're there.
What I like about these pen and ink drawings is that, yes, you're blocking out light/shade, but the shade is what also communicates form - and not in simply the intensity (or lack of intensity) of the shadow - the lines themselves almost trace over the figure of the image. It's an optical illusion - almost.
There's plenty you can do to play with this technique - my favorite seems to work with the tight/loose diadic relationship of the light. I can make tight contour shading in the facial areas and get looser in other places.
These techniques and my technique is nothing new. I don't know why I've been working with pen and ink, except that I find pleasure in it. The vocabulary of pen and ink and the affects created seem very much displaced from how your eye actually perceives lightness, darkness, depth and highlight.
