Yes, I said mud! Here is an underpainting I started using the leftovers from the previous painting. It is made of all the primary colors on my palette mixed together and thinned with mineral spirits and a little medium.
Here is my initial pass scrubbing some of the darker shadows.
Thinning it down some more I cover some of the background area.
At this stage more of the canvas is covered and I am wiping away some of my lighter areas.
The finished underpainting. The underpainting provides a framework and establishes the lights and the darks of the painting.
Next step is to paint with color!