Candela_per_square_metre

Candela per square metre
Candela per square metre
Unit system	SI
Unit of	luminance
Symbol	cd/m2
In SI base units:	cd·m−2

Candela per square metre

SI derived unit of luminance

The candela per square metre (symbol: cd/m²) is the unit of luminance in the International System of Units (SI). The unit is based on the candela, the SI unit of luminous intensity, and the square metre, the SI unit of area.

Quick Facts Unit system, Unit of ...

The nit (symbol: nt) is a non-SI name also used for this unit (1 nt = 1 cd/m²).^[1] The term nit is believed to come from the Latin word nitēre, "to shine".^[2]

As a measure of light emitted per unit area, this unit is frequently used to specify the brightness of a display device. The sRGB spec for monitors targets 80 cd/m².^[3] Typically, monitors calibrated for SDR broadcast or studio color grading should have a brightness of 100 cd/m².^[4] Most consumer desktop liquid crystal displays have luminances of 200 to 300 cd/m².^[5] HDR displays range from 450 to above 1600 cd/m².^[6]

[N 1]
The symbols in this column denote dimensions; "L", "T" and "J" are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.
[N 2]
Standards organizations recommend that photometric quantities be denoted with a subscript "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967
[N 3]
Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.

Share this article:

This article uses material from the Wikipedia article Candela_per_square_metre, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.

[note-dimension-symbol-7] [N 1]
The symbols in this column denote dimensions; "L", "T" and "J" are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.

[note-suffix-v-8] [N 2]
Standards organizations recommend that photometric quantities be denoted with a subscript "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967

[note-alternative-symbol-photometric-9] [N 3]
Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.

[1] [1]
Buser, Pierre; Imbert, Michel (1992). Vision. MIT Press. p. 53. ISBN 978-0-262-02336-8. nit luminance.

[2] [2]
Boyd, RLF, ed. (1992). Astronomical Photometry. Springer. p. 9. ISBN 978-0-7923-1653-4.

[3] [3]
"Multimedia systems and equipment – Colour measurement and management – Part 2-1: Colour management – Default RGB colour space – sRGB". International Electrotechnical Commission. 1999. IEC 61966-2-1.

[4] [4]
"ITU-R BT.2035-7" (PDF). A reference viewing environment for evaluation of HDTV program material or completed programmes. 2013-08-13. Archived (PDF) from the original on 2022-12-20. Retrieved 2022-12-20.

[5] [5]
Hung, Jonathan (May 3, 2010). "Acer Ferrari One 200 Review – More than a Netbook". PC Perspective. Retrieved 2018-01-21.

[6] [6]
"Pro Display Tech Specs". Apple.

[1]

[2]

[3]

[4]

[5]

[6]

[nb 1]

[nb 2]

[nb 3]

v t e		cd/m² (SI unit) ≡ nit ≡ lm/m²/sr	stilb (sb) (CGS unit) ≡ cd/cm²	apostilb (asb) ≡ blondel	bril	skot (sk)	lambert (L)	foot-lambert (fL) = 1 ⁄ π cd/ft²
1 cd/m²	=	1	10⁻⁴	π ≈ 3.142	10⁷ π ≈ 3.142×10⁷	10³ π ≈ 3.142×10³	10⁻⁴ π ≈ 3.142×10⁻⁴	0.3048² π ≈ 0.2919
1 sb	=	10⁴	1	10⁴ π ≈ 3.142×10⁴	10¹¹ π ≈ 3.142×10¹¹	10⁷ π ≈ 3.142×10⁷	π ≈ 3.142	30.48² π ≈ 2919
1 asb	=	1 ⁄ π ≈ 0.3183	10⁻⁴ ⁄ π ≈ 3.183×10⁻⁵	1	10⁷	10³	10⁻⁴	0.3048² ≈ 0.09290
1 bril	=	10⁻⁷ ⁄ π ≈ 3.183×10⁻⁸	10⁻¹¹ ⁄ π ≈ 3.183×10⁻¹²	10⁻⁷	1	10⁻⁴	10⁻¹¹	0.3048²×10⁻⁷ ≈ 9.290×10⁻⁹
1 sk	=	10⁻³ ⁄ π ≈ 3.183×10⁻⁴	10⁻⁷ ⁄ π ≈ 3.183×10⁻⁸	10⁻³	10⁴	1	10⁻⁷	0.3048²×10⁻³ ≈ 9.290×10⁻⁵
1 L	=	10⁴ ⁄ π ≈ 3183	1 ⁄ π ≈ 0.3183	10⁴	10¹¹	10⁷	1	0.3048²×10⁴ ≈ 929.0
1 fL	=	1 ⁄ 0.3048² ⁄ π ≈ 3.426	1 ⁄ 30.48² ⁄ π ≈ 3.426×10⁻⁴	1 ⁄ 0.3048² ≈ 10.76	10⁷ ⁄ 0.3048² ≈ 1.076×10⁸	10³ ⁄ 0.3048² ≈ 1.076×10⁴	10⁻⁴ ⁄ 0.3048² ≈ 1.076×10⁻³	1

Quantity		Unit		Dimension ^{[nb 1]}	Notes
Name	Symbol^{[nb 2]}	Name	Symbol	Dimension ^{[nb 1]}	Notes
Luminous energy	Q_v^{[nb 3]}	lumen second	lm⋅s	T⋅J	The lumen second is sometimes called the talbot.
Luminous flux, luminous power	Φ_v^{[nb 3]}	lumen (= candela steradian)	lm (= cd⋅sr)	J	Luminous energy per unit time
Luminous intensity	I_v	candela (= lumen per steradian)	cd (= lm/sr)	J	Luminous flux per unit solid angle
Luminance	L_v	candela per square metre	cd/m² (= lm/(sr⋅m²))	L⁻²⋅J	Luminous flux per unit solid angle per unit projected source area. The candela per square metre is sometimes called the nit.
Illuminance	E_v	lux (= lumen per square metre)	lx (= lm/m²)	L⁻²⋅J	Luminous flux incident on a surface
Luminous exitance, luminous emittance	M_v	lumen per square metre	lm/m²	L⁻²⋅J	Luminous flux emitted from a surface
Luminous exposure	H_v	lux second	lx⋅s	L⁻²⋅T⋅J	Time-integrated illuminance
Luminous energy density	ω_v	lumen second per cubic metre	lm⋅s/m³	L⁻³⋅T⋅J
Luminous efficacy (of radiation)	K	lumen per watt	lm/W	M⁻¹⋅L⁻²⋅T³⋅J	Ratio of luminous flux to radiant flux
Luminous efficacy (of a source)	η^{[nb 3]}	lumen per watt	lm/W	M⁻¹⋅L⁻²⋅T³⋅J	Ratio of luminous flux to power consumption
Luminous efficiency, luminous coefficient	V			1	Luminous efficacy normalized by the maximum possible efficacy
See also: SI Photometry Radiometry

Candela_per_square_metre

Candela per square metre

Comparison with other units of luminance

See also

References

External links

Share this article: