Sandy Lee Simianer, age 9, of Lowell, Ind., for her question:
WHEN WAS MICROFILM DEVELOPED?
Microfilm is used extensively in education, science and industry. Two or three rolls of microfilm, for example, can store as much information that normally fills four drawers of business records. A few small boxes of microfilm placed on cards can store enough books to make a small library. With microfilm, it is no longer necessary to store bulky records.
Microfilm is a small photographic film on which reduced images of printed and other material are photographed. Because the images are greatly reduced, microfilm can store a tremendously large amount of material in a very small space.
The contents of an entire book can be photographed on a short strip of microfilm only 35 millimeters wide. The strip can then be wound into a small roll and stored in a fraction of the space occupied by the book.
By putting the microfilm copy of the book through a projection machine to enlarge the image, the pages can easily be read on a large viewing screen.
Some projection machines will make an enlarged paper copy of the image on the film. This copy may be made the same size as the original page of the book. Most microfilm is black and white because color is more expensive and usually is not necessary.
The process of making microfilm copies is called microphotography. This process has been known since the very early days of photography. It became a large industry after the Library of Congress in Washington, D.C., started to microfilm their books in about 1928.
Microfiche is the name given to a microfilm strip which has been cut into short pieces and placed in a plastic card. The microfiche measures about four by six inches. Two or three microfiche cards can hold material copied from an entire book.
Single frames cut from a strip of microfilm can also be inserted in punched cards used by high¬speed business machines. Information on microfilm can then be found in just a matter of seconds by running the cards through a special kind of sorting machine.
Similar to microfilm is the filmstrip. In this process, a related series of still pictures are put on film and a projector is used to flash one after another of these pictures on a screen. Teachers use filmstrips for instruction. They are easier to use, can be more easily stored and cost less than slides.
Filmstrips can be made either in black or white or in color. A record player or tape recorder can be attached to the projector to provide sound for the filmstrips.
Although a recorded story to go with a filmstrip is popular, most teachers using the equipment seem to prefer silent equipment which will enable them to explain the pictures themselves or to have a pupil do it. With this method, a student can ask a question immediately instead of having to wait until the end of the recording.