Infrared photography uses film sensitive to light with wavelengths slightly longer than are visible to the naked eye. This shift, when processed, will cause a "false image", where objects normally red appear green and green objects appear blue. The advantage of this method, is that objects that give off heat will appear red, including vegetation.

History

Infrared film was first developed in 1903 and by the 1930's the film system was enhanced for use in landform studies and other research. By the 1940's, the military had made advancements to the film as an enhanced way of detecting camouflaged enemy locations, but eventually gave up on the film when infrared blocking paint was developed.

Uses in Archaeology

Buried archaeological site features will cause slight changes in ground vegetation, by hindering growth and by blocking ground water or the natural movement of the soil. Infrared film's ability to detect the heat signature given off by vegetation makes it possible to see this effect, even though it may not be visible at all from the ground. Features that will disturb vegetation growth can be anything from buried buildings, burial mounds , and well-packed walking paths to fire hearths.

Cost

Infrared film can be used in a normal camera, so the only cost of the pictures is a slightly more expensive film and the cost to get your camera airborne to take the pictures.