Microfilm

From Dead Media Archive

Revision as of 15:44, 6 December 2010 by Slt301 (Talk | contribs)
(diff) ← Older revision | Current revision (diff) | Newer revision → (diff)
Jump to: navigation, search

File: Microfilm1.jpg‎

Contents

What were microforms?

Microfilm is a type of microform. Microforms are miniature reproductions of documents made using photographic techniques. There are three types of microforms -- microfilm (reels of tape, most popular, and the subject of this dossier), microfiche (produced on flat sheets) and microcards (essentially microfiche, but made on cardboard). Microforms are usually images of documents reduced about 25 times from their original size. They are either positive or negative images, but usually negatives, and the individual pieces, before projected through a special reader machine, look similar to slides.


Origins of Microfilm

Microfilm was originally developed in the 1800s, but it was not put into mainstream use until the early 20th century. John Benjamin Dancer created "micro-photographs" in 1839, using the daguerrotype process for photography, and then modified it contemporaneously with advances in photographic techniques, using the collodion process, which allowed for multiple copies of images. This process also used less harmful chemicals and allowed for easier mass production -- both of which helped the advancement of microphotographs as a technology. The technique of micro-photography was not proposed as a method for document preservation until the latter half of the 19th century. The original patent holder for the machine that made microfilm reproductions was George McCarthy, a banker, who used it to create permanent copies of bank records. He called it a "Checkograph" machine and used it to make copes of cancelled checks. The Eastman Kodak Company purchased the rights to the machine in 1928, and moved the technology in a more commercial direction.


What were the main uses of microfilm?

Because of its large storage capacity, microfilm was mainly used for archival purposes. It was originally used for bank records to guard against deterioration as well as to save storage space. The NYtimes starting using microfilm to make copies of their newspapers in the 1930s. Between 1927 and 1935, the Library of Congress used it to make reproductions of 3 million pages of books, and the Harvard University Library started a massive project in 1938 called the "Foreign Newspaper Project" for preservation. The technology was "officially endorsed" by the American Library Association as a way of storing, as well as referencing, materials. Additionally, in a different use, microfilm was actually made useful for communication in the Franco-Prussian War in 1870. Communication was carried between Paris and Tours by pigeon post, and pigeons were not able to carry paper, so they used microfilm to carry large documents in a small format. Once the messages got to their destinations, the microfilms were projected by magic lanterns and copied back onto paper.

File:Microfilm2.jpg

Microfilm Machines

When a document is transferred to microfilm, they can be reduced to 99% of their original size. A microfilm machine basically works the same way as a modern photocopier - a picture is taken, scaled down, and printed. Microfilm images were printed on special black-and-white film. There are two types of film: silver halide and vesicular. The first is similar to film used in most cameras, using a silver emulsion process. The second, uses microscopic bubbles on a polyester strip of film to create the reproduction, and can be exposed to daylight without fading or deteriorating. Microfilm is surprisingly difficult to destroy. It is nearly impossible to tear it by hand or write on it. An eHow.com article says the only two ways to destroy microfilm are to incinerate it or to feed it through a cross-cut shredder. The readers for microforms are essentially big microscopes, with lenses to enlarge the image and an eyepiece to look through. Desktop reading machines look similar to computer screens; Microfilm reels are fed through a track and projected back to the viewer, who uses knobs to magnify and navigate.

File:481_1976_microfilm_lg.jpg

Demise of Microfilm

If stored in the proper conditions, microfilm can last up to 900 years. Since one of the original goals of microfilm was to save space, that goal is being furthered more effectively by digital media. Therefore, microfilm machines are becoming less common, and many companies are converting microform documents to digital scans to make them easier to store, index, and catalog. Digital preservation methods have many advantages over their analog counterparts. One of the main advantages to digital is sharing capacity, as well as actual viewing experience. Microfilm creation machines and readers are still in existence, but it is easier to find a company that will convert your microfilm to digital format than a company that will create new microfilm.

Personal tools