Microforms are microreproductions of documents for transmission,
storage, reading and printing. Microform images are commonly
reduced about 25 times from 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 second. Microforms often come in three formats:
microfilm (reels), aperture cards and microfiche (flat sheets).
Microcards were similar to microfiche, but printed on paper
cardboard rather than photographic films. In the middle of the
twentieth century, microforms became popular in library
communities. Periodicals, books, and other collections were
converted into microform. However, digital preservation has
become increasingly popular, causing the decline of microform
preservation. Microform in the twentieth century Microfom is
used primarily for the preservation of documents, images,
architectural or technological drawings, maps, and other forms
of information. While microform was a primary