 | This article's lead section may be too short to adequately summarize the key points. (February 2024) |
A microform is a scaled-down reproduction of a document, typically either photographic film or paper, made for the purposes of transmission, storage, reading, and printing. Microform images are commonly reduced to about 4% or 1⁄25 of the original document size. For special purposes, greater optical reductions may be used.
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.
Equipment is available that accepts a data stream from a computer; this exposes film to produce images as if the stream had been sent to a line printer and the listing had been microfilmed. The process is known as computer output microfilm or computer output microfiche (COM).