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A foot-candle (sometimes foot candle; abbreviated fc, lm/ft 2, or sometimes ft-c) is a non-SI unit of illuminance or light intensity. The foot-candle is defined as one lumen per square foot. This unit is commonly used in lighting layouts in parts of the world where United States customary units are used, mainly the United States. [1]
The American Society of Cinematographers (ASC) defines lighting ratio as (key+fill):fill, or (key+Σ fill):Σ fill, where Σ fill is the sum of all fill lights. Light can be measured in footcandles. A key light of 200 footcandles and fill light of 100 footcandles have a 3:1 ratio (a ratio of three to one) — (200 + 100):100.
Illuminance diagram with units and terminology. In photometry, illuminance is the total luminous flux incident on a surface, per unit area. [1] 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. [2]
The corresponding unit in English and American traditional units is the foot-candle. One foot candle is about 10.764 lx. One foot candle is about 10.764 lx. Since one foot-candle is the illuminance cast on a surface by a one-candela source one foot away, a lux could be thought of as a "metre-candle", although this term is discouraged because it ...
Several measures of light are commonly known as intensity: Radiant intensity , a radiometric quantity measured in watts per steradian (W/sr) Luminous intensity , a photometric quantity measured in lumens per steradian (lm/sr), or candela (cd)
A tea light-type candle, imaged with a luminance camera; false colors indicate luminance levels per the bar on the right (cd/m 2). Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. [1]
Can we imagine ourselves back on that awful day in the summer of 2010, in the hot firefight that went on for nine hours? Men frenzied with exhaustion and reckless exuberance, eyes and throats burning from dust and smoke, in a battle that erupted after Taliban insurgents castrated a young boy in the village, knowing his family would summon nearby Marines for help and the Marines would come ...
Daylight harvesting systems are typically designed to maintain a minimum recommended light level. [1] This light level will vary according to the needs and use of the space; for example, the commonly recommended light level for offices is 500 Lux (or around 50 foot-candles) on the desktop.