So far, we have our drawing, in graphite, on gessoed board. We then sealed the drawing with clear matte spray paint (6 coats), and use a wash of Burnt Sienna, Ultramarine Blue, and a touch of Aliziran Crimson over the drawing, thinned with Turpenoid.
The drawing has now dried for about an hour, and I have sped up the drying process by using a hairdryer.
I am treating this as an underpainting. The oil wash is not completely dry yet. I then use several things to wipe away the paint, including bristle brushes, paper towels, cotton swabs, and kneadable erasers. Any and all of these tools work. Personally, I prefer using the kneadable erasers, dabbing at the paint, then a small bristle brush to make a smooth transition. Occasionally, I will use the paper towel.
You have about 24 hours or so before the paint becomes permanent. The longer the paint stays on, the harder it is to remove from the image. I will sometimes wait for several hours before beginning to model the image. The window of opportunity to do this does close, however, so be aware.
This monochromatic painting will provide unity for colors that will be applied on top, but that is to be discussed in the next step.
Have a great week!