The second one is done with a water soluble graphite pencil, a Derwent product called Aquatone, more fun than serious. The first one is more an effort to define the shapes and details of direction and interaction between the shapes, and darks and lights. Interesting that each one of these value sketches will make the actual painting part much easier. Working out the positioning and all the changes from the references that I'll make in the final painting.
Addendum: Here's the final painting. The sketches really helped.