Shijune Posted July 31, 2021 Posted July 31, 2021 I have asked this question, but the topic was pulled to a different side which is human color perception. Because of this reason, I did not get a satisfactory answer. I want to ask again the same question more clearly ,taking refuge in your understanding. Thanks in advance. If we think about all possible color hues according to "Lab Color Space" (lightness values)L* and these colors are saturated ( pure hues without lighter shades ), yellow is the second lightest color next to white and it is also the closest color to white. ( I mean here the lightness, not brightness. If we are talking about the brightness, lime green is perceived by human eye as a brighter color than white, because our cones are most sensitive at the 550 nm wavelength.) How can this situation be explained physically ?
beecee Posted July 31, 2021 Posted July 31, 2021 (edited) Don't know if it answers your question or not, but the colour of anything perceived by the eye, in the very first instant, depends on what part of the electromagnetic spectrum, falls upon that eye. eg: What colour is an Orange in the dark? https://www.scienceabc.com/nature/what-color-is-an-orange-in-the-dark.html Edited July 31, 2021 by beecee
Sensei Posted July 31, 2021 Posted July 31, 2021 (edited) 41 minutes ago, Shijune said: How can this situation be explained physically ? Physically, there are only photons with wavelengths from 400 nm to 700 nm or a mixture of them, e.g. perfect white is the same amount of each wavelength. Brightness is result of quantity i.e. dark grey is the same as white, the same/similar composition, same amount for each wavelength, but with smaller quantity. It depends on the human eye, or device, which decide were is point of maximum saturation (maximum quantity) Due to the way human eye is build, we can detect "true" yellow from photons with a wavelength ~580 nm, or "fake" yellow i.e. a mixture of red photons with a wavelength ~650-700 nm and green photons with a wavelength ~550 nm. Computer color spaces have maximum saturation when they reach 255 (in RGB 24 bit, ARGB/RGBA 32 bit). Physically there is no such limit. Therefor programmers created HDRI technology/technique/formats, which can store colors in a floating point format. https://en.wikipedia.org/wiki/High-dynamic-range_imaging Edited July 31, 2021 by Sensei
John Cuthber Posted August 1, 2021 Posted August 1, 2021 The 7 squares in that picture shoe the effects of All 3 sets of dots on my screen illuminated, Just red and green Blue and green Red and blue; and then the 3 primary colours on their own. Since all 3 lights are on in the white square, I see it as brightest. My eye is most sensitive to green, and least sensitive to blue So the mixtures with blue in them are going to be perceived as relatively dark. Thus the mixture without blue, (to which the eye is relatively insensitive) and containing green (at the peak of sensitivity) will be seen as lightest. And that's yellow. It looks lighter than the green for the simple reason that it is. It has the green light and it has the red as well.
Phi for All Posted August 1, 2021 Posted August 1, 2021 16 hours ago, Shijune said: I have asked this question, but the topic was pulled to a different side which is human color perception. Because of this reason, I did not get a satisfactory answer. I want to ask again the same question more clearly ,taking refuge in your understanding. Thanks in advance. ! Moderator Note I would like some assurances that you won't melt down if your ideas are criticized like the last time. It was extremely uncivil, unscientific, and unacceptable. What has changed?
Shijune Posted August 2, 2021 Author Posted August 2, 2021 (edited) On 7/31/2021 at 4:02 PM, Shijune said: I have asked this question, but the topic was pulled to a different side which is human color perception. Because of this reason, I did not get a satisfactory answer. I want to ask again the same question more clearly ,taking refuge in your understanding. Thanks in advance. If we think about all possible color hues according to "Lab Color Space" (lightness values)L* and these colors are saturated ( pure hues without lighter shades ), yellow is the second lightest color of next to white and it is also the closest color to white. ( I mean here the lightness, not brightness. If we are talking about the brightness, lime green is perceived by human eye as a brighter color than white, because our cones are most sensitive at the 550 nm wavelength.) How can this situation be explained physically ? I got this,... Edited September 16, 2021 by Phi for All No advertising, please.
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