Bill is continuing the process of pushing his mountains farther into the background by building up his foreground. He has already darkened the base color because this part of the mountain range is the closest to the viewer. The mountain lake and the water run-off has also receded into background adding to the perspective of the painting.
Also notice how Bill pulls your eye into the center of his painting. Watch in upcoming clips, as he adds more foreground, the way you get “lost” in the painting. Bill did all this “on the fly”. Although he knew exactly where he was going in his painting, he didn’t have to think about it. That’s why, particularly in these video clips, he spends so much time explaining to the viewer where he’s going in the painting.
Never painted before