Engraving

An intaglio technique characterized by clean tapered lines made by incising a metal plate (traditionally copper) with a sharp tool called a burin. A range of line widths is possible depending on the size of tools used, making delicate tonalities also possible. The incised lines hold the ink when the image is pressed. Engraving is the technique most commonly seen in Old Master prints.

Source: http://www.ifpda.org/content/collecting_pr...