Mimeograph
Mimeographs, along with spirit duplicators and hectographs, were common technologies for printing small quantities of a document, as in office work, classroom materials, and church bulletins.
Use of stencils is an ancient art, but – through chemistry, papers, and presses – techniques advanced rapidly in the late nineteenth century: A description of the Papyrograph method of duplication was published by David Owen:[2] A major beneficiary of the invention of synthetic dyes was a document reproduction technique known as stencil duplicating.
Its earliest form was invented in 1874 by Eugenio de Zuccato, a young Italian studying law in London, who called his device the Papyrograph.
This invention provided for more automated, faster reproductions since the pages were produced and moved by rollers instead of pressing one single sheet at a time.
The impact of the type element displaces the coating, making the tissue paper permeable to the oil-based ink.
[12] A variety of specialized styluses were used on the stencil to render lettering, illustrations, or other artistic features by hand against a textured plastic backing plate.
Text from electrostencils had lower resolution than that from typed stencils, although the process was good for reproducing illustrations.
A skilled mimeo operator using an electrostencil and a very coarse halftone screen could make acceptable printed copies of a photograph.
During the declining years of the mimeograph, some people made stencils with early computers and dot-matrix impact printers.
In theory, the mimeography process could be continued indefinitely, especially if a durable stencil master were used (e.g. a thin metal foil).
Spirit duplicated images were usually tinted a light purple or lavender, which gradually became lighter over the course of some dozens of copies.
[18] Gestetner, Risograph, and other companies still make and sell highly automated mimeograph-like machines that are externally similar to photocopiers.
[citation needed] Although mimeographs remain more economical and energy-efficient in mid-range quantities, easier-to-use photocopying and offset printing have replaced mimeography almost entirely in developed countries.
Mimeographs and the closely related but distinctly different spirit duplicator process were both used extensively in schools to copy homework assignments and tests.
They were especially popular with science fiction fans, who used them extensively in the production of fanzines in the middle 20th century, before photocopying became inexpensive.
Because changing ink color in a mimeograph could be a laborious process, involving extensively cleaning the machine or, on newer models, replacing the drum or rollers, and then running the paper through the machine a second time, some fanzine publishers experimented with techniques for painting several colors on the pad.
[19] In addition, mimeographs were used by many resistance groups during World War Two as a way to print illegal newspapers and publications in countries such as Belgium.
