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Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle. Brightness is the term for the ''subjective'' impression of the ''objective'' luminance measurement standard (see for the importance of this contrast). The SI unit for luminance is candela per square metre (cd/m2). A non-SI term for the same unit is the nit. The unit in the Centimetre–gram–second system of units (CGS) (which predated the SI system) is the stilb, which is equal to one candela per square centimetre or 10 kcd/m2. Description Luminance is often used to characterize emission or reflection from flat, diffuse surfaces. Luminance levels indicate how much luminous power could be detected by the human eye looking at a particular surface from a particular angle of view. Luminance is thus an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illuminance
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception.International Electrotechnical Commission (IEC): ''International Electrotechnical Vocabulary.'ref. 845-21-060, illuminance/ref> Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance. In SI units illuminance is measured in lux (lx), or equivalently in lumens per square metre ( lm· m−2). Luminous exitance is measured in lm·m−2 only, not lux. International Electrotechnical Commission (IEC): ''International Electrotechnical Vocabulary.'ref. 845-21-081, luminous exitance/ref> In the CGS system, the unit of illuminance is the phot, which is equal to . The foot-candle is a non-metric unit of illuminance that is used in photography. Ill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candela Per Square Metre
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. The nit (symbol: nt) is a non-SI name also used for this unit (1 nt = 1 cd/m2). The term ''nit'' is believed to come from the Latin word , "to shine". 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 . Typically, monitors calibrated for SDR broadcast or studio color grading should have a brightness of . Most consumer desktop liquid crystal displays have luminances of 200 to 300 cd/m2. HDR displays range from 450 to above 1600 cd/m2. Comparison with other units of luminance One candela per square metre is equal to: *10−4 stilbs (the CGS unit of luminance) *π×10−4 lamberts *π apostilbs *0.292 foot-lamberts *π×103 skots ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brightness
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. The perception is not linear to luminance, and relies on the context of the viewing environment (for example, see White's illusion). Brightness is a subjective sensation of an object being observed and one of the Color appearance model#Color appearance parameters, color appearance parameters of many color appearance models, typically denoted as Q. Brightness refers to how much light ''appears to shine'' from something. This is a different perception than lightness, which is how light something appears ''compared to'' a similarly lit white object. The adjective '':wikt:bbright'' derives from an Old English ''beorht'' with the same meaning via metathesis giving Middle English ''briht''. The word is from a Common Germanic ', ultimately from a Proto-Indo-European language, PIE root w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
