spectral luminous efficiency

efficiency, spectral luminous (of a monochromatic radiation of wavelength λ)

Ratio of the radiant flux at wavelength λ_m to that at wavelength λ such that both radiations produce equally intense luminous sensations under specified photometric conditions and λ_m is chosen so that the maximum value of this ratio is equal to one. Symbols: V(λ) for photopic vision. V′(λ) for scotopic vision (Fig. E1). Note: unless otherwise indicated, the values used for the spectral luminous efficiency in photopic vision are the values agreed internationally in 1931 by the CIE and adopted in 1933 by the International Committee on Weights and Measures. For scotopic vision the CIE in 1951 provisionally adopted new values for young observers (CIE). Syn. luminosity curve.

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Fig. E1 Relative luminous efficiency curves for photopic V_λ and scotopic V′_λ levels of adaptation for an equi-energy spectrum. These data represent the sensitivity (i.e

Table E1 Photopic and scotopic relative luminous efficiency factors. The data are based on an average from a large number of individuals agreed by the CIE in 1931 for the photopic factor V_λ and in 1951 for the scotopic factor V′_λ
wavelength (in nm)	V_λ	V′_λ
380	0.000 0	0.000 589
400	0.000 4	0.009 292
420	0.004 0	0.096 61
440	0.023 0	0.328 1
460	0.060 0	0.567 2
480	0.139 0	0.793 0
500	0.323 0	0.981 8
507	-	1.000 0
520	0.710 0	0.935 2
540	0.954 0	0.649 7
555	1.000 0	-
580	0.870 0	0.121 2
600	0.631 0	0.033 15
620	0.381 0	0.007 374
640	0.175 0	0.001 497
660	0.061 0	0.000 312 9
680	0.017 0	0.000 071 55
700	0.004 1	0.000 017 80
720	0.001 05	0.000 004 78
740	0.000 25	0.000 001 379
760	0.000 06	0.000 000 425
780	0.000 00	0.000 000 139