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About Letterpress
Nov 09 2012 15:57:20 , 3417

Description

A plate for the letterpress method is known as a relief plate. With a relief plate, the picture area is slightly raised above the remainder of the plate. It is a direct printing

method which means that the picture is applied to the substrate directly from the inked plate. Letterpress plates do not need any dampening in the work of the printing method

because only the raised picture areas of the plates receive ink and the non-image areas stay tidy.
The letterpress method is used for some newspaper publishing, labels, and narrow web printing, but it cannot deliver the quality of other printing processes. As a result, it is

a quick diminishing printing method.

Plate Types
The original letterpress plate was constructed with movable metal type mounted in a frame called a chase. Each letter or character had to be arranged in the chase which was time

consuming. The type was also backwards or wrong reading so that when the printed impression was made on the paper, it would appear right reading. The necessity to generate more

efficient methods of letterpress printing led to the development of better plating techniques.
Stereotype: A stereotype plate is created with the use of a mold of the original metal type. Molten metal is poured in to the mold to generate the plate. The plates can be flat

for use on flatbed presses or they can be produced to conform to the shape of the plate cylinder for a rotary press.
Electrotypes: A mold is also used to generate a electrotype plate. The mold is sprayed with a silver coating and it is then electroplated with copper or nickel. The resulting

plate is removed from the mold and the back of the plate is filled with lead or plastic for support.
Photoengraving: The plates are prepared by contacting a film negative with the plate and exposing it to a measured unit of light. The plate is then chemically etched, which

washes out the unexposed, or non-image areas. The etching removes of the plate material in the non-image areas to lead to the picture areas being raised above the non-image

areas. The non-image areas are reduced from the original plate thickness of 0.032" to a thickness of 0.015".