I find this raw sienna - burnt sienna turpentine wash stage important. It will catch some things I may miss during the composition/drafting stage of the painting. For instance, I noticed that the vertical rock wall behind the lion felt too much like a wall and too little like a rock. I made a mental note to curve it at the top to mimic the rock bolder feel I have in the rest of the painting. Also, the curving rock just behind the lion's back was too matchy-matchy with the line of his spine. I moved the rock up and will keep an eye on how it effects the overall composition.
Another change was the lion's mane. In the drawing, I didn't notice the mane seemed a little flat between his eyes. Once I had the wash on, it was obvious to me it needed to be higher. I threw on some darker wash to extend it. The wash also brought to my attention the section to the right of the lioness's back legs. Right now it seems very bright and distracts from the lion. While I paint, I'll want to think about how to resolve this with the planned grasses.
Generally a turpentine wash will take me 1 - 1.5 hours for a painting. This took me 4 hours and it revealed some details and problem areas. It also gives me a sense of the balance of the painting. Does an area need to be darker? Is the painting weighted on one side? What draws my attention and is that the area I intended for the main focus?