Standard cameras can be used for infrared photography provided the film advance and data back systems do not incorporate infrared sensors. Infrared film, which is available in colour or black-and-white, is sensitive to some of the longer wavelengths of electromagnetic radiation not visible to the human eye or panchromatic film. We can therefore produce images influenced by wavelengths that we cannot otherwise see. This opens up new and exciting opportunities for photographing people, but some basic rules must be observed.

Black-and-white infrared film should be stored in a refrigerator and must be loaded and unloaded in complete darkness. Removing the film cassette from the canister or camera in daylight will cause fogging. The most evocative results are achieved using opaque infrared filters that absorb unwanted visible light. A red filter (No 25) is a good alternative. Note that infrared rays do not focus in the same way as visible light. Focus in the normal manner, note the focused distance, and then turn the focusing ring manually until this distance aligns with the infrared focusing mark on the lens. Set the exposure initially to whatever your normal exposure meter indicates, and bracket widely using small or medium apertures. When exposing Kodak HIE infrared film at ISO 200 in direct sunlight, using a red filter, try bracketing around 1/125 second at f/8.

A person's skin is recorded as white if the subject is in direct light. Skin in shadow will be recorded as very dark. Hair and eyes record in broadly the same way as with panchromatic film, but only very dark shades of lipstick will be visible. Fresh green grass and foliage are recorded like frost or snow. Consequently it is possible to create unusual and even surreal images.

Colour infrared film (such as Ektachrome EIR) has only limited application for pictorial work, but is fun to try. It incorporates infrared-sensitive dye and delivers rather unpredictable false-colour images when exposed using a yellow filter. Focusing adjustment is not necessary. The film must be stored in a freezer and used fresh because its infrared characteristics degrade rapidly at room temperature. Like black-and-white infrared film, it must be loaded and unloaded in total darkness to avoid fogging. It can be processed using E6 chemistry.

The black-and-white infrared films currently available are:

• Kodak 2481 IR - available only in 35mm format;
• Ilford SFX 200 - available only in 35mm and 120 formats;
• Maco IR 820C - available in 35mm and 120 formats;
• Maco IR 820 Aura - available in 35mm and 120 formats.

Kodak 2481 IR and Ilford SFX 200 are readily available, but Maco films are subject to limited supply. Black-and-white infrared films should be kept cool and processed promptly after exposure. Colour infrared films may need to be stored in a freezer. Each film has its own character. All tend to be more grainy than conventional black-and-white and colour films, and some respond more strongly to infrared radiation than others. Note that some digital cameras have sensors that are sensitive to infrared radiation.

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