Microforms have a variety of types as discussed in the
introductory post of this blog. These types include microfiche, microfilm,
microcard, and aperture card. Microfilm and microfiche are the most common with
microfilm topping out over microfiche. Microfilm comes in two forms: COM and
what we might call preservation microfilm. COM stands for “computer output
microfilm” which is exactly what it sounds like. Preservation microfilm would
be the reformatting of a document into microfilm. In this instance, it would
not be a far stretch to think of COM as equivalent to digital born materials
such as websites whereas preservation microfilm would be equivalent to
digitized documents.
Below is a recent video from the State Library of South
Australia showing the microfilming of a series of newspapers and the subsequent
storage of these newspapers. According to the video, the shelf life of
newspapers when properly stored is 100 years while the shelf life of modernly
manufactured microfilms (those not prone to vinegar syndrome) is upwards of 500
years with proper care and storage.
The creation of microfilm is best seen as a photographic or film
development process requiring a preconfigured reduction ratio (Kenney and Chapman
1996). Standard microfilm sizes include 16mm, 35mm, 70mm, and 105mm. The most
commonly used size for the purpose of preservation is 35mm microfilm. Kenney
and Chapman (1996) discuss at length the justification for retaining microfilm
(or, more generally, microform) masters in the face of producing digital images
(179-186). This hybrid approach will be discussed in greater length in the post
“Preservation Strategies and Microforming.”
Bibliography
Kenney, A.R. and Chapman, S. (1996). In Digital imaging for libraries and archives. New York: Department of
Preservation and Conservation, Cornell University Library.
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