July 2019
Volume 19, Issue 8
Open Access
OSA Fall Vision Meeting Abstract  |   July 2019
The normal human visual system extracts about 1% of the hues possible from the L, M and S cones compared to a perfect hue encoder
Author Affiliations
  • Sara S. Patterson
    Ophthalmology, University of Washington
  • James A. Kuchenbecker
    Ophthalmology, University of Washington
  • Anna-Lisa Doebley
    Ophthalmology, University of Washington
  • Maureen Neitz
    Ophthalmology, University of Washington
  • Jay Neitz
    Ophthalmology, University of Washington
Journal of Vision July 2019, Vol.19, 81. doi:https://doi.org/10.1167/19.8.81
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      Sara S. Patterson, James A. Kuchenbecker, Anna-Lisa Doebley, Maureen Neitz, Jay Neitz; The normal human visual system extracts about 1% of the hues possible from the L, M and S cones compared to a perfect hue encoder. Journal of Vision 2019;19(8):81. https://doi.org/10.1167/19.8.81.

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      © ARVO (1962-2015); The Authors (2016-present)

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A normalization process makes the average spectral distribution reaching the eye appear achromatic -- white or gray. There are six possible ways the relative activations of L-, M- and S-cones can differ from white. 1) S activity higher, M and L activity relatively lower compared to white; 2) M higher, S and L lower; 3) L higher, S and M lower; 4) M and L higher, S lower; 5) S and L higher, M lower; 6) S and M higher, L lower. Thus, to fully encode hue require six channels, for each of the ways the relative activities of the cones can differ from white. However, humans experience only four hues—1) red, the hue associated with S+L high, M low; 2) green the hue associated with M high, S+L low; 3) blue, associated with S+M high, L low; 4) yellow, associated with L high, S+M low. Thus only two-thirds of the hue information available is encoded and transmitted to the brain.. For example, the difference between a light at 430 nm and a 470+630 nm mixture is entirely a change between the relative activities of S vs. L+M cones, for which we have no hue encoders. Under carefully controlled conditions, when the relative brightness of the lights is adjusted appropriately, a good match is achieved in hue, saturation and brightness. This is a true failure of color vision and since each hue dimension produces about 100 gradations, we only see about 1% of the hues compared to a perfect encoder.


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