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Bril (unit)
The bril is an old, non- SI, unit of luminance. The SI unit of luminance is the candela per square metre. Unit conversions See also * Photometry (optics) Photometry is a branch of optics that deals with measuring light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectr ... Units of luminance Centimetre–gram–second system of units {{optics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. The procedure for conversion from spectral radiance to luminance is standardized by the CIE and ISO. 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 det ... [...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 deprecated 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 display A liquid-crystal display (LCD) is a flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liq ...s have luminances of 200 to 300 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skot (unit)
Skot (symbol: sk) is an old and deprecated measurement unit of luminance, used for self-luminous objects (''dark luminance''). The term comes from Greek , meaning "darkness". Overview The skot to measure the dark luminance () was introduced in 1940 by the (, LiTG) out of a necessity to describe the luminance of self-luminous objects, which differed so much from that of other objects that it was impractical to describe it using commonly used luminance values. Conversion factors for so called "scotopic stilb" () depend on the spectral distribution of the light and were therefore redefined in 1948 by the International Commission on Illumination (, IBK) for a specific color temperature of 2042 K or 2046 K, the temperature of solidification of platinum. Before 1948, the definition was based on a temperature of 2360 K as emitted by a wolfram-vacuum lamp. At this temperature, 1 sk = 10−3 asb. The maximum allowed value is 10 skot to avoid the uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambert (unit)
The lambert (symbol L) is a non- SI metric unit of luminance named for Johann Heinrich Lambert (1728–1777), a Swiss mathematician, physicist and astronomer. A related unit of luminance, the foot-lambert, is used in the lighting, cinema and flight simulation industries. The SI unit is the candela per square metre (cd/m2). Definition 1 lambert (L) = \frac candela per square centimetre (0.3183 cd/cm2) or \frac cd m−2 See also Other units of luminance: * Apostilb (asb) * Blondel (blondel) * Bril Bril is a surname. Notable people with the surname include: * Ben Bril, Dutch boxer *Joel Bril, pen name of Joel Löwe * Matthaeus Bril, Flemish painter *Paul Bril Paul Bril (1554 – 7 October 1626) was a Southern Netherlands, Flemish painter ... (bril) * Nit (nit) * Stilb (sb) * Skot (sk) References {{reflist "Lighting Design Glossary: Luminance" at ''Schorsch Lighting Design Knowledgebase'' Units of luminance Non-SI metric units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apostilb
The apostilb is an obsolete unit of luminance. The SI unit of luminance is the candela per square metre (cd/m2). In 1942 Parry Moon proposed to rename the apostilb the blondel, after the French physicist André Blondel André-Eugène Blondel (28 August 1863 – 15 November 1938) was a French engineer and physicist. He is the inventor of the electromechanical oscillograph and a system of photometric units of measurement. Life Blondel was born in Chaumont, Ha .... The symbol for the apostilb is asb. The apostilb is defined in terms of another unit of luminance, the stilb (sb): :1 asb = 1/ ⋅ 10−4 sb : asb = 1 cd/m2 Table of SI photometry quantities for reference See also Other units of luminance: * Lambert (L) * Skot (sk) * Bril (bril) * Nit (nit) * Foot-lambert (fL) References {{reflist Units of luminance Centimetre–gram–second system of units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stilb (unit)
The stilb (sb) is the CGS unit of luminance for objects that are not self-luminous. It is equal to one candela per square centimeter or 104 nits (candelas per square meter). The name was coined by the French physicist André Blondel around 1920. It comes from the Greek word (), meaning 'to glitter'. It was in common use in Europe up to World War I. In North America self-explanatory terms such as candle per square inch and candle per square meter were more common. The unit has since largely been replaced by the SI unit: candela per square meter 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 .... The current national standard for SI in the United States discourages the use of the stilb.IEEE/ASTM SI 10-2002. ''American National Standard for Use of the International System of Units (SI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candela
The candela (symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source's spectrum, the contribution of each wavelength is weighted by the luminous efficiency function, the model of the sensitivity of the human eye to different wavelengths, standardized by the CIE and ISO. A common wax candle emits light with a luminous intensity of roughly one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured. The word ''candela'' is Latin for ''candle''. The old name "candle" is still sometimes used, as in '' foot-candle'' and the modern definition of '' candlepower''. Definition The 26th General C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Centimetre
The square metre ( international spelling as used by the International Bureau of Weights and Measures) or square meter (American spelling) is the unit of area in the International System of Units (SI) with symbol m2. It is the area of a square with sides one metre in length. Adding and subtracting SI prefixes creates multiples and submultiples; however, as the unit is exponentiated, the quantities grow exponentially by the corresponding power of 10. For example, 1 kilometre is 103 (one thousand) times the length of 1 metre, but 1 square kilometre is (103)2 (106, one million) times the area of 1 square metre, and 1 cubic kilometre is (103)3 (109, one billion) cubic metres. SI prefixes applied The square metre may be used with all SI prefixes used with the metre. Unicode characters Unicode has several characters used to represent metric area units, but these are for compatibility with East Asian character encodings and are meant to be used in new documents. * * * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot-lambert
A foot-lambert or footlambert (fL, sometimes fl or ft-L) is a unit of luminance in United States customary units and some other unit systems. A foot-lambert equals 1/π or 0.3183 candela per square foot, or 3.426 candela per square meter (the corresponding SI unit). The foot-lambert is named after Johann Heinrich Lambert (1728–1777), a Swiss-German mathematician, physicist and astronomer. It is rarely used by electrical and lighting engineers, who prefer the candela per square foot or candela per square meter units. The luminance of a perfect Lambertian diffuse reflecting surface in foot-lamberts is equal to the incident illuminance in foot-candles. For real diffuse reflectors, the ratio of luminance to illuminance in these units is roughly equal to the reflectance of the surface. Mathematically, :L_\mathrm v = E_\mathrm v \times R, where :L_\mathrm v is the luminance, in foot-lamberts, :E_\mathrm v is the illuminance, in foot-candles, and :R is the reflectivity, expressed as a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photometry (optics)
Photometry is a branch of optics that deals with measuring light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ... in terms of its perceived brightness to the human eye. It is concerned with quantifying the amount of light that is emitted, transmitted, or received by an object or a system. In modern photometry, the radiant power at each wavelength is weighted by a luminosity function that models human brightness sensitivity. Typically, this weighting function is the photopic vision, photopic sensitivity function, although the scotopic vision, scotopic function or other functions may also be applied in the same way. The weightings are standardized by the International Commission on Illumination, CIE and International Organization for Standardization, ISO. Photometry is distinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Units Of Luminance
Unit may refer to: General measurement * Unit of measurement, a definite magnitude of a physical quantity, defined and adopted by convention or by law **International System of Units (SI), modern form of the metric system **English units, historical units of measurement used in England up to 1824 ** Unit of length Science and technology Physical sciences * Natural unit, a physical unit of measurement * Geological unit or rock unit, a volume of identifiable rock or ice * Astronomical unit, a unit of length roughly between the Earth and the Sun Chemistry and medicine * Equivalent (chemistry), a unit of measurement used in chemistry and biology * Unit, a vessel or section of a chemical plant * Blood unit, a measurement in blood transfusion * Enzyme unit, a measurement of active enzyme in a sample * International unit, a unit of measurement for nutrients and drugs Mathematics * Unit number, the number 1 * Unit, identity element * Unit (ring theory), an element that is i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
