Infrared photography uses a part of the light spectrum that is not visable to the human eye. Wavelengths used for this kind photography range from about 700 nm to about 900 nm. When using infrared film the film is usually sensative to visible light also, so its recomended that a filter is used that blockes visable light such as an R72 filter. Some digital cameras are near-infrared sensative and can be used in conjunction with a R72 filter. Alternatively you can get DSLR’s modified to see more of the infrared spectrum. This can be expensive! Filters can cost as little as £20 I have a r72 and a 850nm filter that work well with the Fujifilm X100s
Infrared photography produces some very characterisitc results, foliage appears to glow, and be alot brighter than normal, skies are dark and skin can glow as the light penetrates the skin (making sureal portraits)
This example shows the dramatic differance between normal or visible light and infrared light.
Typically infrared photogprahy is monochrome however Kodak released Ektachrome Infrared Color film which produced stunning and sureal results such as pink trees and deep navy blue skies. The advent of digital infrared photogrpahy has seen cdigital processing exploit colour manipulation to create an otherworldly effect to images.