The process was used as early as the 1400's in Europe. The image is cut into a block of wood with straight or scooped knives called gouges. The raised uncut surface holds the ink. Paper is placed over the block and rubbed by hand or a press to transfer the ink from the block to the paper to create the image. Engraving, Etching, Aquatint , and Drypoint are intaglio processes.
Ink is rubbed into the grooves, the areas that hold the ink below the surface of the plate.
The differences between these processes are in how the grooves are made. They are all rolled through a press to print the image onto paper. Engraving is a highly skilled craft that was introduced around 1450. The grooves are cut directly into the metal plate with a burin , a sharp pointed steel rod set into a handle. The burin is pushed across the plate and cuts a clean V-shaped furrow.