The most common type is microfiche, which are flat strips of microfilm images stored in a clear Mylar sleeve, or “jacket” (where jacket fiche gets its name). Jacket fiche comes primarily in two formats, 16mm and 35 mm, and are roughly 4 inches x 6 inches each.
COM fiche (computer output microforms ) are created by printing a computer generated data stream direclty on film. The result is the equivalent of hundreds of miniaturized paper documents, arranged in a grid pattern.
There are two different formats, 24x and 48x, each having to do with the amount of reduction on each image ( 1/24th or 1/48th respectively). Each COM fiche is approximately 105 mm x 148 mm, and holds up to 300 images, thanks to the high reduction rate.
Microfilm or roll film are wound onto a standard size reel, and can accommodate both 16mm and 35mm film. 35mm is more commonly u