Portrait of an high quality old man

This is a portrait of an older man, the face seemed very interesting to me as well as the eyes, i thought it would be an interesting subject to draw. This portrait is done in black biro on a piece of A3 paper, but is around the size of an A4 piece, in the centre of the paper. I will sometimes draw in biro instead of graphitee pencil as I think it is easier to sometimes get moredepth high quality and detail compared to pencil drawings.