The candela per square metre (cd/m2) is the SI unit of luminance; nit is a deprecated non-SI name also used for this unit (1 nit = 1 cd/m2).[1]
Computer displays typically have luminances of 50 to 300 cd/m2; the sRGB spec for monitors targets 80 cd/m2.[2] Modern flat-panel (LCD and plasma) displays often exceed 300 cd/m2. HDTVs range from 450 to about 1000 cd/m2. A luminance of at least 800 cd/m2 is required for a screen to be viewable under direct sunlight.[citation needed]
Nit is believed to come from the Latin niter, to shine.[3] It is sometimes used for marketing purpose to quantify the brightness of some computer displays.
References
- ^ Pierre Buser and Michel Imbert (1992). Vision. MIT Press. p. 53. ISBN 9780262023368. http://books.google.com/books?id=NSZvt8Ld2-8C&pg=PA53&dq=nit+luminance&lr=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=&as_brr=3&as_pt=ALLTYPES&ei=dH3iSfagBYyykASju4yfDQ.
- ^ "IEC 61966-2-1:1999 Multimedia systems and equipment - Colour measurement and management - Part 2-1: Colour management - Default RGB colour space - sRGB". International Electrotechnical Commission. http://webstore.iec.ch/webstore/webstore.nsf/artnum/025408.
- ^ R. L. F. Boyd (ed.) (1992). Astronomical Photometry. Springer. p. 9. ISBN 9780792316534. http://books.google.com/books?id=ojzepXhy9DIC&pg=PA9&dq=nitere+nit+luminance&lr=&as_brr=3&as_pt=ALLTYPES&ei=mn7iSbanFZDakATYjaG6DQ.
See also
- Stilb (luminance) The CGS unit of luminance.
- Liquid crystal display
- Light-emitting diode
- Photometry (optics)
External links
| Quantity | Symbol | SI unit | Abbr. | Notes | ||||
|---|---|---|---|---|---|---|---|---|
| Luminous energy | Qv | lumen second | lm·s | units are sometimes called talbots | ||||
| Luminous flux | F | lumen (= cd·sr) | lm | also called luminous power | ||||
| Luminous intensity | Iv | candela (= lm/sr) | cd | an SI base unit | ||||
| Luminance | Lv | candela per square metre | cd/m2 | units are sometimes called "nits" | ||||
| Illuminance | Ev | lux (= lm/m2) | lx | Used for light incident on a surface | ||||
| Luminous emittance | Mv | lux (= lm/m2) | lx | Used for light emitted from a surface | ||||
| Luminous efficacy | lumen per watt | lm/W | ratio of luminous flux to radiant flux | |||||
| SI • Photometry | ||||||||
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