Here is a short video from a quick portrait sketch yesterday morning. After a one-shot session like this I usually end up with a ton of paint on the canvas from pushing shapes around quickly. This is where scraping down with a palette knife is so useful. In fact, I would say scraping down between sessions at the beginning of a portrait is probably the second most useful thing I learned while studying portraiture (the first being the sight-size technique).
I have a short video of the scraping down process which I’ll add soon.