Katie G. answered 05/13/19
BA recipient with 9 years formal artistic training
Yes! Completely possible! Also what a lot of people do! You can just go to town on your drawing with any grade of charcoal you have, if you are concerned about the graphite repelling the charcoal (it shouldn't) you can hit the drawing with a light dusting of fixative that will give the paper back some of its tooth. Happy drawing!