Also called intaglio printing, the lines to be printed are cut into a metal plate by means of a cutting tool called a burin, held in the hand – in which case the process is called engraving; or through the corrosive action of acid – in which case the process is known as etching. In etching, for example, the plate is covered in a resin ground or an acid-resistant wax material. The plate is then dipped into acid. The acid bites into the surface of the plate where it was exposed.
To print with an engraving plate, ink is applied to the surface of the plate by the press and pushed into the recessed lines, or grooves. The plate is then wiped clean on the surface with a paper material so that ink only resides in the etched impression of the plate, the intended image. A piece of paper is fed into the press and is placed on top of the plate and is squeezed using immense pressure into the plate’s ink-filled grooves. The ink is transferred from the etched area of the plate to the paper and the result is a printed sheet of paper with a raised ink impression.