Many art students find the transition from drawing to painting a bit daunting, because there are so many variables to contend with.
One of the best painting teachers was Harold Speed (1872-1957). A sample of work is shown above. His books on both drawing and painting are among the finest sources of classic art instruction. Speed uses the term “mass drawing” to distinguish it from “outline drawing.”
Mass drawing in monochrome oil paint is one of the transitional steps from drawing to painting. The purpose of mass drawing is to bring students “from simple outlines to approach the full realization of form in all the complexity of light and shade.”
In this demonstration, Speed follows four logical steps:
Step 1. The blocking in of various areas in charcoal.
Step 2. Middletone block-in with lights painted into it
Step 3. Shadows added with dark paint.
Step 4. Refinement and completion.
The Practice and Science of Drawing (still in print), link.
The Science and Practice of Oil Painting, link.
Selection of Speed's Portraits in the National Gallery, link. (thanks, Art4Marc)