Far infrared light
Far infrared light is in the 15μm-1mm region of the electromagnetic spectrum. Unlike near infrared, which can only detect reflected infrared light, far infrared can ‘see’ sources of heat. This makes it useful for thermal imaging. An example use of this would be for fire fighters to seek out bodies in smoky, dark conditions. Everyday infrared photography does not use far infrared light, as it would be too expensive for most people to afford. However, specialised equipment is available for use by businesses and authorities.