The Kneeling man almost fell over in his haste to obey. His face was pockmarked; the scars were thrown into relief by the candlelight. He remained a little stooped when standing, as though halfway through a bow, and he darted terrified looks up at Harry's face.
Harry Potter and the Order of the Phoenix
I don't quite understand what it means by "the scars were thrown into relief by the candlelight". Any thoughts?