Once the most popular printing process, letterpress is now only used for specialized jobs or limited edition (short-run) books. The use of hot metal typesetting really survives only to produce a proof that can then be scanned and printed by offset litho to reproduce the traditional effect.
Letterpress machines have largely been converted to or replaced by flexography, in which the metal type trays of letterpress are replaced by a flexible rubber or polymer plate. Widely used in the packaging industry, flexographic (or ‘flexo’) presses are similar to gravure, using a series of rotating cylinders to collect ink from a reservoir and transfer it onto a web-fed printing material via plate and impression cylinders. Flexo presses can print on materials unsuitable for offset litho, such as cardboard, plastic bags, or waxed paper.