The infrared photography applications are numerous and varied...
Infrared photography can
certain kinds of haze.
This property is particularly
important for long-distance photography on the ground
where the detail
of distant objects is often obscured by haze, and for high
photography from the air.
Actually, infrared photography does not always result in a very marked increase in the range of vision, but it generally increases the contrast of the distant subjects and thus the amount of detail that can be seen. This produces the effect of greater penetration.
Since infrared light is invisible, photography in total darkness can be readily carried out if infrared film is used and the light source is covered with a light-absorbing but infrared-transmitting filter.
This property allows infrared photography application for many special purposes and during night time in situations where a bright flash would be disturbing (or betray the photographer) such as:
Infrared protraits, outdoors or indoors, appear unusual because infrared light causes skin to have a chalky appearance, red lips to appear very pale, and eyes to appear as dark spots. Doctors, however, use infrared photographs for diagnostic purposes.
Infrared photography has been used in forest survey to distinguish between stands of coniferous and deciduous trees. It is also possible to detect the presence of disease in plants and pollution in rivers and other bodies of water.
An important application of
infrared aerial photography in war is its use for determining
water and detecting underwater obstacles off potential
on enemy coastlines. It has been claimed that by comparing infrared and
conventional photographs of average coastal waters, depths to 20 feet
can be determined to an accuracy of 10 percent.
Infrared photographs have been used for the construction of charts, the study of sandbars and silting of navigable channels, the control of erosion and pollution, the charting of currents, and the study of marine life.
Infrared photography application has also been found in seaweed surveys.
Infrared photography, particularly infrared fluorescence photography, has found several applications in criminological investigations, and it is a standard tool in many laboratories for:
Infrared photography has taken a place with chemical, ultraviolet and X-ray study in determining the authenticity of works of art.
Among the special infrared photography applications, mention can be made of: