Microfiche is a type of microform, and consists of a piece of transparent film storing printed information in miniaturized form and read by a special microfiche reader that magnifies the image.
It was invented by Carl O. Carlson, an employee of National Cash Register, in 1961.
The standard size is 105 mm by 148 mm (about 4 by 5.8 inches), the same as ISO A6, and carry a number of micro images, for example of pages from periodicals. They can be stored in open top envelopes which are put in drawers or boxes as file cards, or fitted into pockets in purpose made books.
Images for use on microfiche can be created by a specialist camera, or can be output from a mainframe computer (for example, to print a library catalogue) which is known as Computer Output Microfiche (COM).