footlambert

footlambert
(fL, fl or ftL)
   a unit of luminance, the brightness of a surface. The footlambert describes the luminance of a surface that emits or reflects one lumen per square foot; it is the luminance of a perfectly reflecting surface under an illumination of one footcandle. One footlambert equals 3.426 259 candelas per square meter or about 1.0764 millilambert (mLb). The unit is also spelled foot-lambert or foot lambert. The one-word spelling and symbol fL have been endorsed by the Illuminating Engineering Society of North America (IES) and by the Institute of Electrical and Electronics Engineers (IEEE). (Of course, fL is also the SI symbol for the femtoliter.)

Dictionary of units of measurement. 2015.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Footlambert — WikiV A unit of luminance equal to 1 / Π candela per square foot or to the uniform luminance at a perfectly diffusing surface emitting or reflecting light at the rate of one lumen per square foot. A lumen per square foot is a unit of incident… …   Audio and video glossary

  • footlambert — noun Date: 1925 a unit of luminance equal to the luminance of a perfectly diffusing surface that emits or reflects one lumen per square foot …   New Collegiate Dictionary

  • footlambert — unit of luminance of a surface emitting one lumen per square foot Units of Measurement …   Phrontistery dictionary

  • footlambert — ˈ ̷ ̷| ̷ ̷ ̷ ̷ noun : a unit of luminance equal to the luminance of a perfectly diffusing surface that emits or reflects one lumen per square foot …   Useful english dictionary

  • Conversion of units — is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors. Contents 1 Techniques 1.1 Process 1.2 Multiplication factors …   Wikipedia

  • Photometry (optics) — This article deals with the usage of this term in optics and lighting .Photometry is the science of measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement… …   Wikipedia

  • Foot-lambert — A foot lambert or footlambert (fL, sometimes fl or ft L) is a unit of luminance in U.S. customary units and elsewhere. A foot lambert equals 1/pi candela per square foot, or 3.4262591 candelas per square meter (nits). It is named after Johann… …   Wikipedia

  • APEX system — APEX stands for Additive system of Photographic EXposure, whichwas proposed in the 1960 ASA standardfor monochrome film speed, ASA PH2.5 1960,as a means of simplifying exposure computation.Exposure equationUntil the late 1960s, cameras did not… …   Wikipedia

  • Lambert (Einheit) — Lambert (Einheitenzeichen: la, in der engl. Wikipedia jedoch L, in der slovakischen Lb zu finden) ist in den USA die gebräuchliche Einheit der Leuchtdichte, benannt nach dem deutschen Physiker, Mathematiker und Philosophen Johann Heinrich Lambert …   Deutsch Wikipedia

  • Leuchtdichte — Die Leuchtdichte Lv (engl. luminance) ist das photometrische Maß für das, was Menschen als Helligkeit wahrnehmen, also für die Lichtstärke pro Fläche. Eine Lichtquelle mit einer vorgegebenen Lichtstärke erscheint umso heller, je kleiner ihre… …   Deutsch Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”