Above is where this painting currently stands. Below you will see an earlier stage. The drawing was first done on the canvas with conte and graphite, and then I went over those lines with diluted oil paint. The next step was to fill in the darkest areas of the painting, simplifying while simultaneously being as accurate as possible with value and hue.
After those dark areas were blocked in, it was much easier to judge the adjacent values. Against a white surface, everything can look too dark, which is why many artists start by toning their canvas. The paint here is still very thin, slightly diluted with OMS, yet note that it is not a monochromatic under painting but a chromatic under painting. This will make a great base for the following layers of paint.
I may get to work on this some more tonight, but then in the morning I am leaving for the weekend. I'll report back about this when I return next week.