A2, charcoal pencils and graphite, pastel for background.
Image ref by kind courtesy of Brian Grossman (legalizeeverything in Deviantart).
These older pics below... which I've recently discovered in an old folder. I've no idea if I'm reposting these, nor about the reference image source of at least the first one (so I heartily thank whomever it was for helping me with these studies)
And this one, is a study after a Lucian Freud painting...(hard pastels, water-solubles) No idea about size, probably A3.