Film Media
Photographic film has a layer of emulsion attached to a polyester base material. The image is created in the emulsion by chemical response to light and is fixed there by processing with other chemicals.
The various types of media falling under this category are:
a) Film-strip:
It is a collection of images which take two different forms: the single or half-frame, and the double - or full-frame. The single-frame strip is usually passed through the viewer or projector vertically, whereas the double-frame strip is projected horizontally. Film-strips are generally supplied in small circular canisters and are accompanied by notes explaining the content of the images in the individual strips.
b) Slide:
The photographic slide, sometimes referred to as a transparency is a single frame cardboard or plastic frame. Glass is sometimes used to cover and protect the film within the mounting frame. Slides are produced in various formats of different dimensions, starting with 35 mm. and going up to 250 mm square, the latter is suitable for use with the help of an Overhead Projector.
C) Cine film:
The cine film is a sequence of images. When these images are projected on a screen at the correct speed, the images give the appearance of a continuous movement. The cine films are issued in various formats: 35 mm and 16 mm with sound-track, 16 mm without sound, and 8 mm which is now obsolete (the old stock of 8 mm films have now been transferred on to videotapes or videodiscs).
d) Microforms:
There are various types of microforms, such as, 35 mm roll-film, 16 mm roll-film; aperture cards; and microfiche.
Care and Handling of Film Media
Good care and maintenance of film materials, which are concerned with the following points, constitute the basic procedures for their long-term preservation.
The films should be changed and inspected after each use. This can be done by using soft brush or puffer. Those items, which are not frequently used, should be inspected regularly and rewound at intervals.
The equipments used for screening/display must be kept clean and dust free. In handling, films should not be jarred or dropped. This may produce scratches.
Use of bent containers or reels should be avoided. This can damage films severely.
Films should be handled only by the edges, and should not be twisted.
Film materials taken out of the air-conditioned storing, should be allowed to reach room temperature before these are screened/displayed.
Film materials should be projected/viewed only by equipments mounted safely.
Only qualified staff should be allowed to handle the media and the equipments.
Film materials should be stored out of sun-light, which bleaches. In sunlight colours fade with prolonged exposure.
Films should be stored in dust free containers. The polyester base attracts dust, which damages the film surface.
The containers should not be composed of materials harmful to film materials, such as those having acidic, sulfur or peroxide contents.
Glass covering even film may induce formation of Newton's rings if trace of water is trapped between two layers. The rings are rainbow-like effects which change shape with the heat of projection. So, films under glass cover should be absolutely dry.
High humidity encourages bacterial and fungal growth in photographic emulsions and high temperature affects films badly in the long run. Hence humidity and temperature of the storing area should be as prescribed earlier.
0 Comments