Microform - Media

Media

Flat film

105 x 148 mm flat film is used for micro images of very large engineering drawings. These may carry a title photographed or written along one edge. Typical reduction is about 20, representing a drawing that is 2.00 x 2.80 metres, that is 79 x 110 in. These films are stored as microfiche.

Microfilm

16 mm or 35 mm film to motion picture standard is used, usually unperforated. Roll microfilm is stored on open reels or put into cassettes. The standard lengths for using roll film is 30.48 m (100 ft)for 35mm rolls, and 100 ft, 130 ft and 215 feet for 16mm rolls. One roll of 35 mm film may carry 600 images of large engineering drawings or 800 images of broadsheet newspaper pages. 16 mm film may carry 2,400 images of letter sized images as a single stream of micro images along the film set so that lines of text are parallel to the sides of the film or 10,000 small documents, perhaps cheques or betting slips, with both sides of the originals set side by side on the film.

Aperture cards

Aperture cards are Hollerith cards into which a hole has been cut. A 35 mm microfilm chip is mounted in the hole inside of a clear plastic sleeve, or secured over the aperture by an adhesive tape. They are used for engineering drawings, for all engineering disciplines. There are libraries of these containing over 3 million cards. Aperture cards may be stored in drawers or in freestanding rotary units.

Microfiche

A microfiche is a flat film 105 x 148 mm in size, that is ISO A6. It carries a matrix of micro images. All microfiche are read with text parallel to the long side of the fiche. Frames may be landscape or portrait. Along the top of the fiche a title may be recorded for visual identification. The most commonly used format is a portrait image of about 10 x 14 mm. Office size papers or magazine pages require a reduction of 24 or 25. Microfiche are stored in open top envelopes which are put in drawers or boxes as file cards, or fitted into pockets in purpose made books.

Ultrafiche

(also 'ultramicrofiche') is an exceptionally compact version of a microfiche or microfilm, storing analog data at much higher densities. Ultrafiche can be created directly from computers using appropriate peripherals. They are typically used for storing data gathered from extremely data-intensive operations such as remote sensing.