Using a multitude of various charcoals and tools here. Of particular usefulness as of late: Prismacolor Art Stix for upper-tier halftones and incredibly light values. It doesn't play with other media so well due to the strong wax content and a heavy application really puts this into high relief; but strategically used—it's perfect for gentle, light, and subtle gradations of value. Especially on really light or bright white surfaces where subtle slight value shifts can be difficult to keep tamed.
