Encyclopedia of Color Science and Technology

Living Edition
| Editors: Ronnier Luo

Spectral Luminous Efficiency

  • János Schanda
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27851-8_327-1



Spectral luminous efficiency (of a monochromatic radiation of wavelength λ) [V(λ) for photopic vision; V′(λ) for scotopic vision] (see CIE e-ILV [1])

Ratio of the radiant flux at wavelength λm to that at wavelength λ such that both produce equally intense luminous sensations under specified photometric conditions and λm is chosen so that the maximum value of this ratio is equal to 1.

Unit: 1


By the end of the nineteenth century, photometry achieved a level where it became necessary to describe the light perception efficiency of radiation of different wavelengths. Several methods were used to determine the spectral luminous efficiency function (called also spectral visibility). The two most important ones were direct comparison and the flicker method (based on the fact that if two lights are seen alternatively with increasing frequency, first the sensation of...


Luminance Level Foveal Vision Relative Visibility Scotopic Vision Blue Lead Light 
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  1. 1.
    CIE e-ILV item 17–1222 in http://eilv.cie.co.at/term/1222
  2. 2.
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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • János Schanda
    • 1
  1. 1.University of PannoniaVeszprémHungary