Even though I said I wouldn't, I worked more on this painting today. While I was working I thought to take pictures to share the process with you. I started by making corrections to the drawing I previously posted and then adding some detail to the contour. Then, I used a cheap, large bristle brush to brush off loose charcoal from the canvas. (This, by the way, is an oil-primed polyester canvas.)
Brushing off the loose charcoal helps make way for the paint, or else the first half of all your strokes only serve to clear a path in the charcoal for future strokes of paint. As I go along with a small brush (this is always the brush I go to for outlining and small detail) I further refine the edge, showing the character of the contour.
Here it is with the outline complete and a few very small areas of shadow filled in.
Next, I fill in the shadow areas with thinned burnt umber using a coarse bristle brush. I've been wondering if I should've softened the edges on the shadows, but I do like how this way I see a simple pattern of light and shadow with no gray area between.
Finally, I add some middle gray mix to the background, mostly just because I want to cover the canvas and have something to judge the light areas of the figure against. Those light areas will be saved for another day, however.