Re: Humans (and cameras and scanners) do not have a color gamut (?)
This gets a bit off-topic, but it is relevant to the prior discussion and may be of interest to some on this list.
On Mon, 13 Jan 2020 12:52:18 -0500, Henry Davis <davishr@bellsouth.net <mailto:davishr@bellsouth.net>>wrote:
One can find all sorts of expert ?scholarly? work about how animals percieve color. You bring up tetrachromatic, and there are other theories out there about animal perception. They are thrown around as ?facts? when a few decades ago they would have only been counted as speculations.
At this point, Henry, you are simply displaying a broad ignorance of science, and in particular, biophysics, which makes further discussion difficult. Yes, there was a lot that was not known about the physiology of “animal vision,” including color perception (and a lot of other science!) decades ago, and much has been learned since then. When I was in grad school working on my PhD in biophysics (electrophysiology), much of the science involving the electrophysiology of photoreception was in its infancy. Neher and Sakmann received the Nobel Prize in 1991 for their development of the “patch clamp” technique that allowed the measurement of femtoamp currents passing through single ion channel molecules in cell walls. I spent more time writing software for data acquisition and analysis and Markov modeling than I did doing experiments. It was a very exciting time during which many of the fundamental mechanisms of cell physiology, photoreception, phototransduction and vision were unraveled. A lot has been learned since then, as the result of a lot of hard, meticulous work by dedicated scientists. Vision is a phenomenally complex process, and although much of it is now fairly well understood and is not controversial, color perception is still an active area of research. Regarding what’s known: there is an excellent online summary of the science behind the organization of the retina here: https://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-re... and color vision here: https://webvision.med.utah.edu/book/part-vii-color-vision/color-vision/ and color perception here: https://webvision.med.utah.edu/book/part-viii-psychophysics-of-vision/color-... This is not a collection of "a lot of theories being waved around.” This is now scientific consensus. Regarding what’s not known and is currently under investigation, look here: Visual perception - https://www.sciencedirect.com/journal/current-opinion-in-behavioral-sciences... There are some fascinating articles in this special issue volume, including a review of cone fundamentals and CIE standards. Other articles are mentioned below. The 36 or so articles can be downloaded free. It is accepted fact that color vision processing in the primate visual system is initiated by absorption of light by three different spectral classes of cones. Therefore, color vision is described as being trivariant or trichromatic. You can find graphs of the spectral sensitivities of the S-cone, M-cone, and L-cones online (above). These spectral sensitivities have been measured, they are not hypothetical. If you are colorblind, you do not perceive color as most people do. This is also not controversial. Most colorblindness is due to missing or defective cones. The molecular genetics behind most colorblindness is now also fairly well understood. Tetrameric color vision is not “hypothetical” or “theoretical." There are humans (women) with tetrachromacy, who have a fourth type of cone. To match the sensory effect of arbitrarily chosen spectra of light within their visual spectrum requires mixtures of at least four primary colors. It was once thought that this was exceptionally rare in humans, but that remains an open question. It is certainly not common. (http://www.digitaljournal.com/article/326976, https://www.bbc.com/future/article/20140905-the-women-with-super-human-visio...). There is a great article on tetrachromacy in humans in the volume mentioned above (Tetrachromacy: the mysterious case of extra-ordinary color vision. https://www.sciencedirect.com/journal/current-opinion-in-behavioral-sciences...) Most birds are known to have retinas with four spectral cone types that mediate tetrachromatic color vision. The fourth cone is variable across avian species, but it primarily detects ultraviolet light. There are also pigmented oil droplets in the photoreceptor cells of birds that filter light before it gets to the outer edge of the cells, that give birds a larger color spectrum than that of humans. To study how birds might use this tetrameric system, the scientists in the article I sent previously created a tetrameric, spectral-based camera that mimicked real animal spectral sensitivities that allowed them to visualize the raw data that would be collected by photoreceptors. This cutting edge research was published in one of the most respected scientific journals in the world. (https://www.nature.com/articles/s41467-018-08142-5) In this era where there has been a great loss of respect for science, and tons of misinformation and false information spread across the internet, I think it is important to remain grounded on the scientific basis of our understanding of the world. Engineers certainly will, as even the avian research described above could be useful in designing sensors with better detection abilities for collision avoidance systems on vehicles, and so on. Understanding and modeling the world around us has been, and will continue to be, the basis for a lot of innovation. —Rich
I’m as happy to admit my ‘broad’ ignorance as much as you are happy to point it out. Did you gain a talent for being snarky during or after working on your PhD? Here’s the thing: with all of the explaning you’ve not addressed the point I was making, points you left out of your response. Scientists have done wonderfully complex studies of the sensors/eyes, they’ve followed pathways into the brain, they’ve observed responses. They show us examples of animal vision. In spite of all of this I believe they are ignorant of what an animal apprehends - here there is no proof, only speculation. I’ve been told that dogs can hear higher frequencies than I can. I’m betting that they can - but since I can’t hear it I can’t say for sure just exactly how it sounds to them. I’m ignorant of that as well. You’ve stood up for science. Now tell me, what do animals actually see? Henry Davis
On Jan 13, 2020, at 5:02 PM, Rich Wagner via colorsync-users <colorsync-users@lists.apple.com> wrote:
This gets a bit off-topic, but it is relevant to the prior discussion and may be of interest to some on this list.
On Mon, 13 Jan 2020 12:52:18 -0500, Henry Davis <davishr@bellsouth.net <mailto:davishr@bellsouth.net>>wrote:
One can find all sorts of expert ?scholarly? work about how animals percieve color. You bring up tetrachromatic, and there are other theories out there about animal perception. They are thrown around as ?facts? when a few decades ago they would have only been counted as speculations.
At this point, Henry, you are simply displaying a broad ignorance of science, and in particular, biophysics, which makes further discussion difficult. Yes, there was a lot that was not known about the physiology of “animal vision,” including color perception (and a lot of other science!) decades ago, and much has been learned since then. When I was in grad school working on my PhD in biophysics (electrophysiology), much of the science involving the electrophysiology of photoreception was in its infancy. Neher and Sakmann received the Nobel Prize in 1991 for their development of the “patch clamp” technique that allowed the measurement of femtoamp currents passing through single ion channel molecules in cell walls. I spent more time writing software for data acquisition and analysis and Markov modeling than I did doing experiments. It was a very exciting time during which many of the fundamental mechanisms of cell physiology, photoreception, phototransduction and vision were unraveled.
A lot has been learned since then, as the result of a lot of hard, meticulous work by dedicated scientists. Vision is a phenomenally complex process, and although much of it is now fairly well understood and is not controversial, color perception is still an active area of research. Regarding what’s known: there is an excellent online summary of the science behind the organization of the retina here: https://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-re... and color vision here: https://webvision.med.utah.edu/book/part-vii-color-vision/color-vision/ and color perception here: https://webvision.med.utah.edu/book/part-viii-psychophysics-of-vision/color-... This is not a collection of "a lot of theories being waved around.” This is now scientific consensus. Regarding what’s not known and is currently under investigation, look here: Visual perception - https://www.sciencedirect.com/journal/current-opinion-in-behavioral-sciences... There are some fascinating articles in this special issue volume, including a review of cone fundamentals and CIE standards. Other articles are mentioned below. The 36 or so articles can be downloaded free.
It is accepted fact that color vision processing in the primate visual system is initiated by absorption of light by three different spectral classes of cones. Therefore, color vision is described as being trivariant or trichromatic. You can find graphs of the spectral sensitivities of the S-cone, M-cone, and L-cones online (above). These spectral sensitivities have been measured, they are not hypothetical. If you are colorblind, you do not perceive color as most people do. This is also not controversial. Most colorblindness is due to missing or defective cones. The molecular genetics behind most colorblindness is now also fairly well understood.
Tetrameric color vision is not “hypothetical” or “theoretical." There are humans (women) with tetrachromacy, who have a fourth type of cone. To match the sensory effect of arbitrarily chosen spectra of light within their visual spectrum requires mixtures of at least four primary colors. It was once thought that this was exceptionally rare in humans, but that remains an open question. It is certainly not common. (http://www.digitaljournal.com/article/326976, https://www.bbc.com/future/article/20140905-the-women-with-super-human-visio...). There is a great article on tetrachromacy in humans in the volume mentioned above (Tetrachromacy: the mysterious case of extra-ordinary color vision. https://www.sciencedirect.com/journal/current-opinion-in-behavioral-sciences...)
Most birds are known to have retinas with four spectral cone types that mediate tetrachromatic color vision. The fourth cone is variable across avian species, but it primarily detects ultraviolet light. There are also pigmented oil droplets in the photoreceptor cells of birds that filter light before it gets to the outer edge of the cells, that give birds a larger color spectrum than that of humans. To study how birds might use this tetrameric system, the scientists in the article I sent previously created a tetrameric, spectral-based camera that mimicked real animal spectral sensitivities that allowed them to visualize the raw data that would be collected by photoreceptors. This cutting edge research was published in one of the most respected scientific journals in the world. (https://www.nature.com/articles/s41467-018-08142-5)
In this era where there has been a great loss of respect for science, and tons of misinformation and false information spread across the internet, I think it is important to remain grounded on the scientific basis of our understanding of the world. Engineers certainly will, as even the avian research described above could be useful in designing sensors with better detection abilities for collision avoidance systems on vehicles, and so on. Understanding and modeling the world around us has been, and will continue to be, the basis for a lot of innovation.
—Rich
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I believe even trichromat human vision comes in more nuances; just in my family, in my case think i have a slight R pigment mutation which is mostly seen in women and rarely men. Which I guess for a fashion photographer was an advantage since much fashion is intended to speak to women. And my son seems to see something at dusk - a glow- around some objects, I think it’s IR, and when you think of that it would give a hunter a big advantage to have built-in FLIR :) but I dont know what channel is creating this sensation. We may have started to understand the physiology but I don’t think we’re quite there yet with the perception of color. Science is rarely finished, it is more often like a mountain road, or a Proust novel, as you move up you see more clearly the road below, but major surprises always await, and the view from above casts new light on what you already passed through. On Mon, Jan 13, 2020 at 11:02 PM Rich Wagner via colorsync-users < colorsync-users@lists.apple.com> wrote:
This gets a bit off-topic, but it is relevant to the prior discussion and may be of interest to some on this list.
On Mon, 13 Jan 2020 12:52:18 -0500, Henry Davis <davishr@bellsouth.net <mailto:davishr@bellsouth.net>>wrote:
One can find all sorts of expert ?scholarly? work about how animals percieve color. You bring up tetrachromatic, and there are other theories out there about animal perception. They are thrown around as ?facts? when a few decades ago they would have only been counted as speculations.
At this point, Henry, you are simply displaying a broad ignorance of science, and in particular, biophysics, which makes further discussion difficult. Yes, there was a lot that was not known about the physiology of “animal vision,” including color perception (and a lot of other science!) decades ago, and much has been learned since then. When I was in grad school working on my PhD in biophysics (electrophysiology), much of the science involving the electrophysiology of photoreception was in its infancy. Neher and Sakmann received the Nobel Prize in 1991 for their development of the “patch clamp” technique that allowed the measurement of femtoamp currents passing through single ion channel molecules in cell walls. I spent more time writing software for data acquisition and analysis and Markov modeling than I did doing experiments. It was a very exciting time during which many of the fundamental mechanisms of cell physiology, photoreception, phototransduction and vision were unraveled.
A lot has been learned since then, as the result of a lot of hard, meticulous work by dedicated scientists. Vision is a phenomenally complex process, and although much of it is now fairly well understood and is not controversial, color perception is still an active area of research. Regarding what’s known: there is an excellent online summary of the science behind the organization of the retina here: https://webvision.med.utah.edu/book/part-ii-anatomy-and-physiology-of-the-re... and color vision here: https://webvision.med.utah.edu/book/part-vii-color-vision/color-vision/ and color perception here: https://webvision.med.utah.edu/book/part-viii-psychophysics-of-vision/color-... This is not a collection of "a lot of theories being waved around.” This is now scientific consensus. Regarding what’s not known and is currently under investigation, look here: Visual perception - https://www.sciencedirect.com/journal/current-opinion-in-behavioral-sciences... There are some fascinating articles in this special issue volume, including a review of cone fundamentals and CIE standards. Other articles are mentioned below. The 36 or so articles can be downloaded free.
It is accepted fact that color vision processing in the primate visual system is initiated by absorption of light by three different spectral classes of cones. Therefore, color vision is described as being trivariant or trichromatic. You can find graphs of the spectral sensitivities of the S-cone, M-cone, and L-cones online (above). These spectral sensitivities have been measured, they are not hypothetical. If you are colorblind, you do not perceive color as most people do. This is also not controversial. Most colorblindness is due to missing or defective cones. The molecular genetics behind most colorblindness is now also fairly well understood.
Tetrameric color vision is not “hypothetical” or “theoretical." There are humans (women) with tetrachromacy, who have a fourth type of cone. To match the sensory effect of arbitrarily chosen spectra of light within their visual spectrum requires mixtures of at least four primary colors. It was once thought that this was exceptionally rare in humans, but that remains an open question. It is certainly not common. ( http://www.digitaljournal.com/article/326976, https://www.bbc.com/future/article/20140905-the-women-with-super-human-visio...). There is a great article on tetrachromacy in humans in the volume mentioned above (Tetrachromacy: the mysterious case of extra-ordinary color vision. https://www.sciencedirect.com/journal/current-opinion-in-behavioral-sciences... )
Most birds are known to have retinas with four spectral cone types that mediate tetrachromatic color vision. The fourth cone is variable across avian species, but it primarily detects ultraviolet light. There are also pigmented oil droplets in the photoreceptor cells of birds that filter light before it gets to the outer edge of the cells, that give birds a larger color spectrum than that of humans. To study how birds might use this tetrameric system, the scientists in the article I sent previously created a tetrameric, spectral-based camera that mimicked real animal spectral sensitivities that allowed them to visualize the raw data that would be collected by photoreceptors. This cutting edge research was published in one of the most respected scientific journals in the world. ( https://www.nature.com/articles/s41467-018-08142-5)
In this era where there has been a great loss of respect for science, and tons of misinformation and false information spread across the internet, I think it is important to remain grounded on the scientific basis of our understanding of the world. Engineers certainly will, as even the avian research described above could be useful in designing sensors with better detection abilities for collision avoidance systems on vehicles, and so on. Understanding and modeling the world around us has been, and will continue to be, the basis for a lot of innovation.
—Rich
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participants (3)
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edmund ronald
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Henry Davis
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Rich Wagner