Microform

Microform, Forms with microreproductions of documents.

Microform image

Forms with microreproductions of documents "Microfilm" redirects here. For the digital collection of ebooks, see Internet Archive §:Microfilm collection. For microforming, the industrial microfabrication process, see Microfabrication §:Microforming. Digital scanning of microfilm (see Digital conversion below).

Microforms are scaled-down reproductions of documents, typically either films or paper, made for the purposes of transmission, storage, reading, and printing. Microform images are commonly reduced to about 4% or one twenty-fifth of the original document size. For special purposes, greater optical reductions may be used.

All microform images may be provided as positives or negatives, more often the latter.

Three formats are common: microfilm (reels), microfiche (flat sheets), and aperture cards. Microcards, also known as "micro-opaques", a format no longer produced, were similar to microfiche, but printed on cardboard rather than photographic film.

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History

Using the daguerreotype process, John Benjamin Dancer was one of the first to produce microphotographs, in 1839. He achieved a reduction ratio of 160:1. Dancer refined his reduction procedures with Frederick Scott Archer's wet collodion process, developed in 1850–51, but he dismissed his decades-long work on microphotographs as a personal hobby and did not document his procedures. The idea that microphotography could be no more than a novelty was an opinion shared in the 1858 Dictionary of Photography, which called the process "somewhat trifling and childish".

Microphotography was first suggested as a document preservation method in 1851 by the astronomer ...read more

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