What Kind of Microfilm Do You Have?

At SunRise we often receive requests from organisations that have microfilm records but are unsure of the specific types of microfilm they have. To assist with identification our simple guide introduces the various types found in microfilm libraries.

Microfilm (Roll Film).

Available in 2 main widths – 16mm and 35mm. Usually, the 16mm width is used to film legal size or A4 documents and is generally at 24 times magnification. 16mm also comes in 2 types – blipped and un-blipped.  35mm width to film large documents or plans. The film wraps around a spool and is the oldest and least expensive form as it can store a large amount of information in a small place.

Blipped Microfilm.

The blips in 16mm Blipped microfilm can be cross referenced to a database to make it easy to find images precisely. The operator would look up the image required in the database and they would be told of its film number and image location. The correct film would then be loaded and the location number entered into a key pad that controls the carrier. The film would then be transported at high speed until it stops at the correct location.

Microfiche (Fiche).

Microfiche is a sheet of film, usually 105mm x 148mm (A6), containing multiple images arranged in standardised columns and rows. Microfiche can be produced from duplicated (often described as a diazo) jacketed microfilm. The top of the microfiche sheet contains identification information that can be read without magnification. As these are copies they tend to have a blue coloured finish to them.

Cartridges.

A microfilm cartridge is simply roll microfilm that has been placed in a compact plastic holder. A cartridge has the same characteristics as roll film but helps protect the microfilm from fingerprints and dust but is essentially used as it makes the film easier to load.

Jacketed Microfilm.

A microfilm jacket is an acetate or polyester carrier that contains three to five sleeves or channels into which strips or single images of either 16mm or 35mm roll microfilm are inserted. The top of the jacket contains an index area, which can be typed or written on. A jacket allows a file to be updated – new material can be inserted into the unused channels.

Aperture Cards.

An aperture card is a piece of card rectangular window which is used to display either one frame of 35mm. The card can be keypunched, notched, colour coded, or manually indexed for retrieval.

16mm Duplex Microfilm.

16mm microfilm generally has one image per frame, known as Simplex. Sometimes you will come across Duplex which has two images per frame. Duplex will hold two channels of images – scanned at 48x magnification – it contains up to four times as many images as its Simplex counterpart.

Combination (Jacketed) Microfilm.

As the name suggests this form of jacketed microfilm consists of both 16mm and 35mm film. It consists of one row of 35mm film and three rows of 16mm film.

35mm (Jacketed) Microfilm.

35mm versions of jacketed microfilm contain only 6 frames on 35mm roll film.

Find Out More About Microfilm

Should you require further assistance we’ll be happy to help, contact us by email at info@sunriseimaging.co.uk, by telephone on 020 8255 2011 or via the Contact Form below.