Working out problems before going big

I am planning to tackle a larger canvas than usual, so I wanted to work out some color studies and compositional arrangements on the small scale first.  This is going to be a figure-in- landscape piece, and I have the model and location already selected.  I like to work from a combination of photo reference and painted studies, so I made a couple trips to the location on my own to determine which light condition would work better, morning or late afternoon.  For the specific spot I had in mind it was morning for sure, so I took some photos and painted a two hour 6x8 study.

As you can see, the photograph has compressed variations in hue, temperature and saturation.  These three elements of color are crucial when trying to capture atmospheric depth.  The small study gives me a working color palette drawn from direct observation. 

With the resources gathered for the landscape portion of the painting, I now turned to the figure (who in this case happens to be my wife).  We headed to the location (about an hour north of Phoenix, where we live) and photographed many poses in a few spots, just to have some options. 

I selected the above pose as I liked the light and shadow shapes and subtle expression on her face.  Since the face would be the focal point of the larger painting, I wanted to paint a more detailed head study. 

Now I have all of the components I will need for the large painting.  I bring the photos into Photoshop and begin to play with composition arrangements.  I don't have to worry too much about merging and blending images together since I have my color resources done in paint.  All I need is an arrangement of shapes.  Specifically, I am thinking in terms of value shapes that are clearly articulated and work well in unison.

Here is my composition.  Squinting at the black and white version gives a good impression of the massing of value shapes that will be key to maintain in order for this to be a strong painting.