Technical Information from The Photographers Centre

FILM TYPES AND THEIR USES
There are many makes of film on the market and the choice of film type and manufacturer is eventually a personal one. Some photographers use only film from one maker whilst others will use one brand of colour film and choose a different manufacturer for black and white work. With black and white photography the personal choice is extended to the developer used as this can effect the characteristics of the film used.

FILM TYPES
There are three types of film generally available.

  • 1. Black and white film is usually a negative film designed to be printed.
  • 2. Colour negative film. (designed to be printed)
  • 3. Colour slide film. (Transparency film is an alternative name for slide film)

FILM SPEED
Most films are available in different film speeds; the speed of the film is an indication of how quickly the film reacts to light. A slow film reacts slowly so it either needs a long time or a large amount of light. A fast film can be used under poorer light or where long exposures must be avoided. Slow films are generally sharper and have smaller grain size; fast films have larger grain size and so usually appear to be less sharp. In colour; generally the faster the film the less colour saturation there is.

  • Slow films have an ISO rating of 25-50
  • Medium speed films have an ISO rating of 100-200
  • Fast films have an ISO rating of 400
  • Very fast films have an ISO rating of 1600 and above.
Black and white and colour slide film can be uprated and push processed to increase the speed.
In theory colour negative film is not designed to be "uprated".

FILM AND THE COLOUR OF LIGHT
Black and white film can be exposed under any colour light and although this may affect the contrast there are no colour considerations to worry about. Colour film however is "balanced" for specific colour temperatures. The most common type of film is balanced for "daylight" and if there is no indication on the film then it can be assumed that it is designed to be exposed under daylight. Colour slide film is available in a form designed for use under tungsten light which is the colour of light created by an ordinary 100 watt light bulb. When using tungsten balanced film all other light must be avoided. Colour print film is not readily available for use under tungsten light and so a filter must be used either over the lights, or the camera lens, or at the printing stage. (it is usually cheaper to correct when taking the picture as correcting at the printing stage is expensive).
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The Photographers Centre, Bradninch Place, Gandy Street, Exeter EX4 3LS

Tel: 01392 432617