Re: When neutral 50% gray isn't 50%: elementary gamma question

From: Marco Al (m.f.al_at_student.utwente.nl)
Date: 10/07/04

  • Next message: Marco Al: "Re: When neutral 50% gray isn't 50%: elementary gamma question" 
    Date: Thu, 07 Oct 2004 05:21:12 +0200

    Graham Jones wrote:

    > I'll try one more time. Let's say the 'native' gamma of a monitor is
    > 2.5, meaning (luminance out) is proportional to (voltage in)^2.5. When
    > people talk about gamma=2.2 for PC monitors they mean that a small
    > correction is applied to make the monitor behave like (pixel value)^2.2.

    No the problem is noone agrees with eachother :)

    Find the common denominator between these :

    http://www.poynton.com/notes/colour_and_gamma/GammaFAQ.html

    http://www.w3.org/Graphics/Color/sRGB
    http://www.mi.tj.chiba-u.jp/download/doctor/pdf/PhD_Katoh_wColor.PDF

    http://www.cis.rit.edu/research/mcsl/research/PDFs/GibsonFairchild.pdf
    http://www.art-si.org/PDFs/CRT_Colorimetry_Ap_2002.pdf

    > (sensation out) = (luminance in)^(1/1.8).

    Perception of differences in luminance is approximately logarithmic, so
    it should cancel out against gamma. Some of the images at the following
    page tell a different tale though :

    http://aim-dtp.net/aim/evaluation/perception/perception.htm

    Marco

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