580

optical radiation for which the wavelengths are longer than those for visible radiation, from 780 nm to 1 mmNOTE 1 For infrared radiation, the range between 780 nm and 1 mm is commonly subdivided into:IR-A: 780 nm to 1400 nm, or 0,78 µm to 1,4 µm;IR-B: 1,4 µm to 3,0 µm;IR-C: 3 µm to 1 mm.NOTE 2 A precise border between "visible" and "infrared" cannot be defined, because visual sensation at wavelengths greater than 780 nm is noted for very bright sources at longer wavelengths.NOTE 3 In some applications the infrared spectrum has also been divided into "near," "middle," and "far" infrared; however, the borders necessarily vary with the application (e.g. in meteorology, photochemistry, optical design, thermal physics, etc.).