White Charcoal best Skull Drawing - 9in x 12in

I recently created this piece using white charcoal/white pastel of various forms (compressed, powder, and pencil). It was done on black mixed media paper and sprayed with a fixative to prevent smudging. Although it has been sprayed, the spray only protects it best to a certain extent so handle with care since rubbing can cause the charcoal to smudge.