microfilm

An archival, or preservation and storage, medium in which written material, such as official or personal letters, newspapers, and other printed ephemera, are photographed using a technique that reduces the size of the document to at least one-quarter of its original size. This allows for large volumes of space to be saved, as the microfilm can contain hundreds of documents in one roll, while also providing easy-to-read photographic reproductions that degrade at a slower rate than paper documents. To view microfilmed material, the reel of film must be inserted into a special magnifying device that then brings the image up on a screen while enlarging it back to its original size. Microfilm technology has in great part been replaced by digitized versions of these same sources, although many repositories still retain microfilm collections.