oh my god that's way better than a photograph. from a black and white photograph! that's amazing. I love how you did the white on his face. Can I ask, is the scratching on the surface pencil? (hope that's not a dumb question)...it almost looks like scratches in sand. Anyway, absolutely brilliant.
Basically, the way I work is to do an pencil drawing first and then seal it with fixative or matte medium. Then I go in and lay in semi-transparent washes in acrylics, sometimes with a brush, sometimes airbrushed. After that I'll add detail and highlights with colored pencils and also some more acrylics (like the hair in this piece).
A lot of Illustrators used to work this way, Drew Struzan being the master of the technique. I've been working this way off and on for about ten years. I keep trying other things as well, but this...makes sense to me, and I always seem to come back to it.
Thanks for the comment, I hope that answers your question!
(I see you're from Nova Scotia...I've got a lot of family in Cape Breton!)