Talk:Scotopic vision

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define photopic, mesopic and scotopic vision and give examples of each in everyday occurances.where do the peaks of photopic and ssotopic vision lie in the vissilbe spectrum

Wrong luminance range?[edit]

The current (unsourced) luminance range given for scotopic vision is below 10^-3.5 cd/m^2. This paper[1] gives 10^-3 cd/m^2 and cites a CIE report. Which (if either) is correct? --Rgalexandervision (talk) 16:09, 13 January 2016 (UTC)

Any sourced value, with citation, would be OK. If someone finds another, we can talk. Dicklyon (talk) 16:35, 13 January 2016 (UTC)

wrong evolution?[edit]

I wonder why at scotopic vision, smaller wavelengths are more important for good perception, than in photopic vision. Wouldn't it be more advantageous the other way, as the ambient light at night is far more red than blue? By looking at CIE Illuminant A (night) and C (day) and comparing them with scotopic and photopic vision, one can see that for day it does make sense, but our night vision would be better if the eye wouldn't swich to scotopic but stay with photopic vision. I can not find an explanation for this, it simply does not follow the rules of evolution.--TeakHoken193.187.211.118 (talk) 10:11, 23 January 2008 (UTC)

Seems I found the answer: Illuminant A does not simulate a night illumination. I don't know where I got that from, but it is wrong. I can not find a source that shows a spectrum of a typical illumination at night. But I assume it is more in the blue than in the red. At least when the moon is shining.--TeakHoken193.187.211.118 (talk) 13:17, 10 March 2009 (UTC)

A complete guess, but I think that all light, regardless of the luminence, is composed of various wavelengths of visible light. That is to say, that if our cones were able to "work" at the typical nighttime luminence values, then we'd still have color vision at night. Light at night isn't more blue, it's just darker, and we can't use color vision because we only have one type of cell interpreting the light. As far as evolution goes, I guess color wasn't as important during the night (when we wouldn't be foraging for food) so it wasn't developed in earnest. But I really have no clue how our eyes evolved :)

Also, from reading the article on rod cells, it seems that they are much better at detecting small movements, though not quickly or with great acuity. This might serve as a adaption to keep vigilant at night, wary of potential predators. Lime in the Coconut 19:49, 17 March 2010 (UTC)

colour discrimination vs perception[edit]

The article mentions a lack of colour discrimination, but what about perception? I noticed, for example, that the light pollution in the sky looks distinctly "blue" to me and fades to "orange" towards the brighter areas (sodium lighting). This might explain the blue colouring used to simulate moonlight in movies etc, when in fact (in answer to the above) it is white light (moon is grey, acts just like a very dim sun). (Not sure whether I should be using US English spelling "color" here.)--Adx (talk) 10:24, 21 April 2010 (UTC)