Lux

lux
A lux meter for measuring illuminance
General information
Unit systemSI
Unit ofilluminance
Symbollx
Conversions
1 lx in ...... is equal to ...
   SI base units   cdsrm−2
   US customary units   0.0929 fc
   CGS units   10−4 ph

The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI).[1][2] It is equal to one lumen per square metre. In photometry, this is used as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface. It is analogous to the radiometric unit watt per square metre, but with the power at each wavelength weighted according to the luminosity function, a model of human visual brightness perception, standardized by the CIE and ISO.[3] In English, "lux" is used as both the singular and plural form.[4] The word is derived from the Latin word for "light", lux.

  1. ^ International Bureau of Weights and Measures (2019-05-20), The International System of Units (SI) (PDF) (9th ed.), ISBN 978-92-822-2272-0, archived from the original on 2021-10-18
  2. ^ CIE (2020). CIE S 017:2020 ILV: International Lighting Vocabulary, 2nd edition (2 ed.). CIE.
  3. ^ ISO/CIE 23539:2023 CIE TC 2-93 Photometry — The CIE system of physical photometry. ISO/CIE. 2023. doi:10.25039/IS0.CIE.23539.2023.
  4. ^ NIST Guide to SI Units. Chapter 9 – Rules and Style Conventions for Spelling Unit Names, National Institute of Standards and Technology.

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