The word engraving is used generally to indicate that the grooves in a plate are made directly, without the use of acid. But engraving is also a technique with a precise meaning and a particular tool, called a burin. The burin has a v-shaped blade, and the artist pushes it through the metal rather than drawing in the normal way. The blade is designed to remove the metal on both sides of the incision you are creating as you draw. As you push the tool forward, a thin curl of copper spirals away. Engraved lines swell slightly from their narrow, tapered beginnings and endings, the places where the tool entered and left the plate.