Each painting I make begins with a drawing. I draw with the brush, directly onto a toned canvas. Most of the time I use a mixture of Burnt Umber and White. I will do several drawings, one over the other, so the first drawing must be done in a value just slightly darker than my canvas. I then make progressively darker drawings until I feel that the drawing is accurate enough to continue.If I know in advance I have several sittings on a portrait, I will stop when the drawing is complete and let the painting dry. If I make a mistake in painting on the second sitting I can simply wipe off the paint and my dry drawing is still underneath.With a still-life I try to put in as much information as possible. The better the drawing the easier it is to make the painting.
I always add "I've never made a drawing better by filling it in with paint".....It's still my favorite part of the process.