In the first painting (The blue brush) I started with an thin wash of burnt sienna, a dark translucent orange, that gave the finished painting an overall warm look. In the second painting, after adding a few more elements to the composition the same process was followed, with this painting, however, I started with a light blue mixture that resulted in a painting with a cooler feel.
I wish I had taken a few pictures of the process to post here, maybe I'll do it next time.