The process of incising for drypoint creates a slightly raised ragged rough edge to the lines, known as the burr. When ink that has been applied to the plate is wiped off both the incised line and specifically the burr receive ink when the plate is wiped, giving the printed line a distinctive velvety look. Owing to the delicate nature of the burr, drypoint is usually made in small editions, stopping before the burr is crushed by the pressure of the intaglio press.

Text is borrowed from Tate gallery

https://www.tate.org.uk/art/art-terms/d/drypoint