† Temperatures of black bodies for which spectral peaks fall at the given wavelengths, according to Wien's displacement law

A comparison of a thermal image (top) and an ordinary photograph (bottom) shows that a trash bag is transparent but glass (the man's spectacles) is opaque in long-wavelength infrared.

NIR and SWIR is sometimes called "reflected infrared", whereas MWIR and LWIR is sometimes referred to as "thermal infrared". Due to the nature of the blackbody radiation curves, typical "hot" objects, such as exhaust pipes, often appear brighter in the MW compared to the same object viewed in the LW.

CIE division scheme

The International Commission on Illumination (CIE) recommended the division of infrared radiation into the following three bands:

Abbreviation Wavelength Frequency IR-A 700 nm – 1400 nm (0.7 µm – 1.4 µm) 215 THz – 430 THz IR-B 1400 nm – 3000 nm (1.4 µm – 3 µm) 100 THz – 215 THz IR-C 3000 nm – 1 mm (3 µm – 1000 µm) 300 GHz – 100 THz