(mezzo = half and tinta = tone), a reverse engraving process used on a copper or steel plate to produce illustrations in relief with effects of light and shadow. The surface of a master plate is roughened with a tool called a rocker so that if inked, it will print solid black. The areas to be white or grey in the print are rubbed down so as not to take ink. It was widely used in the 18th and 19th centuries to reproduce portraits and other paintings, but became obsolete with the introduction of photoengraving.