Candela per square metre
From Wikipedia, the free encyclopedia
(Redirected from Nit (unit))
"Nit (unit)" redirects here. For the unit of information entropy, see Nat (information).
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.
[edit] 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.
[edit] See also
- Stilb (luminance) The CGS unit of luminance.
- Liquid crystal display
- Light-emitting diode
- Photometry (optics)
[edit] External links
SI photometry units
| 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 | ||||||||
