Here's a quick watercolor painting experiment that I did this afternoon. First, I put a wash of blue ink on some vintage sheet music from the early 1900s. I then applied Gesso in the middle of the page. I dried the Gesso with my trusty heat gun. Next, I made a quick sketch of a female face - and applied watercolor paint and watercolor pencil to enhance the image.
I've tried this Gesso/watercolor technique before. It's interesting how the Gesso background allows you to (both) wipe out areas of paint - and add additional paint to your composition.
My goal was to make a quick watercolor study - and not strive for perfection. Sometimes, I think you can learn more from your materials when you work fast.