Ask and you shall receive...
Early stages of the pencil (Prismacolor and Verithin) phase (that's a scrap piece of paper under my hand to keep things clean and free of oil). You can use colors here, but since the details were going to be fairly dark, I stuck with black. Once this is done, the drawing is sprayed with fixatif.
The acrylic wash goes on to establish the lightest local colors and values. I also painted in the blacks with black acrylic... no details yet. After the acrylics are done, a layer of watercolor in darker values is laid down on top, and while it is still slightly damp, a semi-dry brush is used to pull out the lighter values.
Here, the other flat colors have been laid in as well. Then, the oil wash of Dioxazine Purple, Permanent Green and Permtine is applied. The oil wash unifies the color palette and drops the overall value a few steps with a nice neutral tone. After 20 or 30 minutes, I begin to use a kneaded eraser to pull off the areas that need to be brightened. After this step, it's just a matter of going in with colored pencils, oils and or acrylics to refine the details. I then masked off the foreground elements with acetate and airbrushed acrylics for the sky and clouds (an optional step).
This is a close-up of the hands...you can really see the grain of the pencils. Also, the oil wash tends to accentuate the natural tooth of the Strathmore 240 (cold press) board.
Here's the face up close. It sounds like a very involved technique, and it is, but once you get the steps down, it's pretty fast. Hope this sheds some light on this nutty technique!