This node contains a table of data for relative sensitivity of the human eye to various wavelengths of light.Wavelengths are in nanometers, sensitivities are relative to the eye's peak sensitivity at 555 nm.

  • 400nm - 0.0004
  • 410nm - 0.0012
  • 420nm - 0.0040
  • 430nm - 0.0116
  • 440nm - 0.023
  • 450nm - 0.038
  • 460nm - 0.060
  • 470nm - 0.091 -- some blue LEDs emit at this wavelength
  • 480nm - 0.139
  • 490nm - 0.208
  • 500nm - 0.323
  • 510nm - 0.503
  • 520nm - 0.710
  • 530nm - 0.862
  • 540nm - 0.954
  • 550nm - 0.995
  • 555nm - 1.000
  • 560nm - 0.995 -- 565 nm is the wavelength of peak emission for common green LEDs
  • 570nm - 0.952
  • 580nm - 0.870
  • 590nm - 0.757 -- 595nm is a clear yellow with some green. Sodium streetlights emit at 589nm - you know, those god-awful intensely yellow lights they use to light up roads (and my bedroom) at night
  • 600nm - 0.631
  • 610nm - 0.503
  • 620nm - 0.381
  • 630nm - 0.265 -- 635nm is emitted by common orange LEDs and 'ultra bright' laser pointers
  • 640nm - 0.175
  • 650nm - 0.107
  • 660nm - 0.061
  • 670nm - 0.032 -- most laser pointers emit at this wavelength
  • 680nm - 0.017
  • 690nm - 0.0082
  • 700nm - 0.0041 -- common deep red LEDs emit at 697nm
  • 710nm - 0.0021
  • 720nm - 0.00105
  • 730nm - 0.00052
  • 740nm - 0.00025
  • 750nm - 0.00012
  • 760nm - 0.00006
Infrared remote control LEDs often emit at 940nm.

Luminous intensity of a light source is measured in candela - a measurement that takes into account how bright the light source looks instead of just how many photons it is emitting. This is probably why super-bright green LEDs have the current highest mcd rating of any LED - they emit at close to the human eye's maximum sensitivity, thus appearing really, really bright.

Table of spectral sensitivities taken from Documenta Geigy Scientific Tables 6th edition, published 1962. See page 239

The above data fed through gnuplot:

   1 ++------+--------+-------XXX------+-------+-------+--------+------++
     +       +        +     X +  X     +       +       +        +       +
     |                                                                  |
 0.9 ++                            X                                   ++
     |                     X                                            |
 0.8 ++                                                                ++
     |                               X                                  |
     |                                                                  |
 0.7 ++                  X                                             ++
     |                                                                  |
 0.6 ++                                X                               ++
     |                                                                  |
     |                                                                  |
 0.5 ++                X                X                              ++
     |                                                                  |
     |                                                                  |
 0.4 ++                                   X                            ++
     |                                                                  |
 0.3 ++               X                                                ++
     |                                      X                           |
     |                                                                  |
 0.2 ++             X                        X                         ++
     |            X                                                     |
 0.1 ++                                        X                       ++
     |         X X                               X                      |
     +      XX        +       +        +       +  X    +        +       +
   0 X+XX-X--+--------+-------+--------+-------+----X-XX-X-XX-X-XX-----++
    400     450      500     550      600     650     700      750     800
It is worth observing that one should distinguish between two vision types: photopic and scotopic.
In these two different "states" of the eye the spectral response changes. It would be useful to know to which state the above curve and data refer.

Anyway, in scotopic vision the rod cells are engaged, and the eye becomes more sensitive to short wavelenghts, that's to say the peak shifts towards blue (the rods peak at 500 nm)

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