Talk:Contrast (vision)

mandatory and authoritative definitions

The mandatory and authoritative definitions are from CIE (Commission International de l'Éclairage), they are as follows:

CIE ILV 17-251 contrast 1. in the perceptual sense: assessment of the difference in appearance of 2 or more parts of a field seen simultaneously or successively (hence: brightness contrast, lightness contrast, colour contrast, simultaneous contrast, successive contrast, etc.)

2. in the physical sense: quantity intended to correlate with the perceived brightness contrast, usually defined by one of a number of formulae which involve the luminances of the stimuli considered: for example by the proportional variation in contrast near the luminance threshold, or by the ratio of luminances for much higher luminances.

References

CIE S 017/E:2011 ILV: International Lighting Vocabulary (expensive printed version of the standard)

http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=845-02-47 online version

The article should be modified accordingly.

panjasan (talk) 12:38, 29 June 2016 (Unhkl)

Manoj panchal

hi i am manoj parmar — Preceding unsigned comment added by 103.251.227.233 (talk) 06:56, 3 April 2014 (UTC)

Request for more readability

I would like to see this article -- or a related article -- that was readable for a laymen like myself. Thanks. Bdbluesman (talk) 21:11, 9 December 2015 (UTC)

"Hard color" listed at Redirects for discussion

An editor has identified a potential problem with the redirect Hard color and has thus listed it for discussion. This discussion will occur at Wikipedia:Redirects for discussion/Log/2022 July 29#Hard color until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Steel1943 (talk) 21:27, 29 July 2022 (UTC)

Explanation of the decrease in contrast sensitivity at low spatial frequencies

The text states that the decrease in contrast sensitivity at low spatial frequencies is from lateral inhibition in retinal ganglion cells. But this is uncited. Hence, this assertion cannot be used for the last sentence, which I have deleted: "By using coarse gratings, the bright bands fall on the inhibitory as well as the excitatory region of the ganglion cell resulting in lateral inhibition and account for the low-frequency drop-off of the human contrast sensitivity function." What this explanation implies is that there are no retinal ganglion cells in our retinas with sufficiently large receptive fields so that the bright parts of a grating can fall on the centre region and so the dark parts of a grating can fall on a surround. The citation, and the text, need to incude evidence of the latter, if indeed it is true. Robert P. O'Shea (talk) 12:40, 11 September 2023 (UTC)