Color perception of your con-species
- eldin raigmore
- korean
- Posts: 6353
- Joined: 14 Aug 2010 19:38
- Location: SouthEast Michigan
Color perception of your con-species
This was supposed to be a questionnaire. If I don't do it right please help.
What wavelengths of electromagnetic radiation can your con-species perceive and focus into an image?
Which ones can they tell apart?
If their atmosphere is like Earth's, they can't see anything shorter than 200 millimicrons (frequency 1.5 petahertz (1.5 * 10^15 Hz), because the atmosphere is opaque to wavelengths shorter than that.
But I haven't been able to find any mention of any real-life terrestrial natspecies that can see wavelengths shorter than 300 millimicrons (1 petahertz).
Assuming their biology is like ours -- water-based -- they probably can't "see" (that is, focus and form images with, as opposed to merely "detect") radiation with a wavelength longer than about 1450 millimicrons (1.45 microns, frequence about 2 terahertz or 2 * 10^12 Hz), because water is opaque to infrared longer than that.
But AFAICT all earth-based color-vision uses a subset of just four optically-sensitive pigments, a UV one, a "short" one, a "medium" one, and a "long" one. Different species have managed to shift the peaks of the response curves for some of these to slightly shorter or slightly longer wavelengths, but, still, the "long" sensor doesn't sense IR light much longer than something between 740 and 780 millimicrons.
If they're warm-blooded, they're probably "blind" to IR light longer than 740 to 780 millimicrons anyway, because their eyes glow in that frequency. But maybe their eyes hang out of their bodies and are cooler than the rest of their bodies, like testicles.
The militaries' active IR night-vision systems detect light between 750 and 1000 millimicrons (300 to 400 Terahertz).
Pit-vipers' pits respond to IR light up to about 2000 millimicrons long (150 Terahertz).
I don't quite understand what I've read about an "IR transmissivity window" for Earth's atmosphere; it's either up to 5000 millimicrons (5 microns) or up to 50000 millimicrons (50 microns). Either way, the frequency is still in the Terahertz range, and water scatters most of it so that it can't be focused into an image by a biological lens. Pit vipers detect its direction quite well, using a "pinhole" focussing system; but it's hardly image-forming.
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So:
What's the shortest wavelength, highest frequency EM radiation your conspecies can detect and focus and use to perceive images? If it's shorter than 200 millimicrons, why?
What's the longest wavelength, highest frequency EM radiation your conspecies can detect and focus and use to perceive images? If it's longer than 1450 millimicrons, why?
What's the just-noticeable difference in their "color perception" of EM radiation? Is it different at different parts of the spectrum? Is less than 10 millimicrons (say they can tell the difference between 500 millimicrons and 505 millimicrons)? Between 10 and 20? between 20 and 50? between 50 and 100?
How many different light-perceiving pigments do your conspecies' eyes have?
Do they use oil-drops in their cone-cells, like some birds and some reptiles, to make the cone-cells better able to tell the difference between shorter and longer wavelengths?
How many different kinds of cone-cells do they have? (Mantis shrimp are said to have 12 or 13 types of cone cells. They can have any of 4 types of light-sensitive pigment; and they can have either no oil-drop or any of 5 kinds of oil-drop.)
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Mantis shrimp can perceive four kinds of linearly polarized light and two kinds of circularly polarized light.
I have no idea what that sentence means. But it means that mantis shrimp can tell exactly everything there is to tell about how light is polarized.
How good are your conspecies at detecting polarization and discriminating between different kinds of polarization of light?
What wavelengths of electromagnetic radiation can your con-species perceive and focus into an image?
Which ones can they tell apart?
If their atmosphere is like Earth's, they can't see anything shorter than 200 millimicrons (frequency 1.5 petahertz (1.5 * 10^15 Hz), because the atmosphere is opaque to wavelengths shorter than that.
But I haven't been able to find any mention of any real-life terrestrial natspecies that can see wavelengths shorter than 300 millimicrons (1 petahertz).
Assuming their biology is like ours -- water-based -- they probably can't "see" (that is, focus and form images with, as opposed to merely "detect") radiation with a wavelength longer than about 1450 millimicrons (1.45 microns, frequence about 2 terahertz or 2 * 10^12 Hz), because water is opaque to infrared longer than that.
But AFAICT all earth-based color-vision uses a subset of just four optically-sensitive pigments, a UV one, a "short" one, a "medium" one, and a "long" one. Different species have managed to shift the peaks of the response curves for some of these to slightly shorter or slightly longer wavelengths, but, still, the "long" sensor doesn't sense IR light much longer than something between 740 and 780 millimicrons.
If they're warm-blooded, they're probably "blind" to IR light longer than 740 to 780 millimicrons anyway, because their eyes glow in that frequency. But maybe their eyes hang out of their bodies and are cooler than the rest of their bodies, like testicles.
The militaries' active IR night-vision systems detect light between 750 and 1000 millimicrons (300 to 400 Terahertz).
Pit-vipers' pits respond to IR light up to about 2000 millimicrons long (150 Terahertz).
I don't quite understand what I've read about an "IR transmissivity window" for Earth's atmosphere; it's either up to 5000 millimicrons (5 microns) or up to 50000 millimicrons (50 microns). Either way, the frequency is still in the Terahertz range, and water scatters most of it so that it can't be focused into an image by a biological lens. Pit vipers detect its direction quite well, using a "pinhole" focussing system; but it's hardly image-forming.
-------------------------------------------------------------------------------------------------------
So:
What's the shortest wavelength, highest frequency EM radiation your conspecies can detect and focus and use to perceive images? If it's shorter than 200 millimicrons, why?
What's the longest wavelength, highest frequency EM radiation your conspecies can detect and focus and use to perceive images? If it's longer than 1450 millimicrons, why?
What's the just-noticeable difference in their "color perception" of EM radiation? Is it different at different parts of the spectrum? Is less than 10 millimicrons (say they can tell the difference between 500 millimicrons and 505 millimicrons)? Between 10 and 20? between 20 and 50? between 50 and 100?
How many different light-perceiving pigments do your conspecies' eyes have?
Do they use oil-drops in their cone-cells, like some birds and some reptiles, to make the cone-cells better able to tell the difference between shorter and longer wavelengths?
How many different kinds of cone-cells do they have? (Mantis shrimp are said to have 12 or 13 types of cone cells. They can have any of 4 types of light-sensitive pigment; and they can have either no oil-drop or any of 5 kinds of oil-drop.)
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Mantis shrimp can perceive four kinds of linearly polarized light and two kinds of circularly polarized light.
I have no idea what that sentence means. But it means that mantis shrimp can tell exactly everything there is to tell about how light is polarized.
How good are your conspecies at detecting polarization and discriminating between different kinds of polarization of light?
My minicity is http://gonabebig1day.myminicity.com/xml
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- cuneiform
- Posts: 92
- Joined: 12 Aug 2010 05:54
Re: Color perception of your con-species
I'd like to answer these, even partially, but I don't know for my species. Their atmosphere has a slightly higher level of CO2, is slightly thicker because their planet is more massive, and their star is smaller than Sol, so it gives off more red light and less blue (and UV?). So, I'm still unsure what colors or how they would see.
Re: Color perception of your con-species
Daron is hotter than the sun, so it produces slightly stronger UV. Agyon can see in the near-UV range (400-250), and have a fourth cone for doing so. Though they look white to humans (and their natural prey), their bodies are covered in a rainbow of colors only visible to them, making identifying each other easy across distances, even during a snowstorm.
Re: Color perception of your con-species
One of my species see quite wide range going from high UV to IE mostly because there is little light where they live (not completely absent) and hence have evolved it
Re: Color perception of your con-species
I know I've considered this question for my conbiology in the past, but those scraps of paper must have disappeared long before I bought my first computer.
I think your question (What wavelengths of electromagnetic radiation can your con-species perceive and focus into an image?) may be a little too homocentric for me to offer an answer beyond "none that I know of". We know from our own subjective experience that sight and heat are separate 'senses', though they're in fact the same thing at different frequencies. Sight is probably perceived as an 'image' by us because the organs that collect those frequencies are highly localised to one part of the body, and processed in specific parts of the brain, whereas the perceptors for heat frequencies are distributed across the entire skin, thus we perceive it as a 'feeling'. So creatures that have a much wider distribution of light receptors across their body might model changes in the visual spectrum as a feeling rather than as images.
You mention pit vipers. I wonder if the positioning of their pit organ (between the eyes and nostrils) acts as a 'third eye', adding to the visual images their eyes create - effectively an additional 'colour'? Maybe some brave scientist has already done the work to see if the brain circuits for the eyes and the pit organ interact/overlap, in which case the answer would probably be: yes.
The parietal eyes of a few vertebrate species can detect light radiation, but don't make use of rods and cones. I've no idea how data from these organs are interpreted alongside the more image-like information from the regular eyes. Given their connection to a specific part of the brain separate from the visual regions I suspect it might be as a separate sense rather than being integrated into the image. (I do know that the main effect of my pineal gland on me is to tell me when I'm tired - a feeling rather than an image.)
Electric eels detect EM at around 25Hz through perceptors distributed through their skin - so probably another feeling: two different types of heat? If you add in the pressure sensors in the lateral line that would make 3 different sources of information (4 including sound waves), like cones - I wonder if electric eels can 'visualise' their surroundings like we (or cows with their all-round sight) see it?
Conbiologically, I quite like the idea of having an animal perceive/use radio waves - it shouldn't be too difficult to explain/develop as radio waves work by inducing an electric current in a metal wire. Heck, if the real world can come up with electric eels, then why not this? If the radio wave receptors were limited to, say, the microwave range (1-2mm) in antenna close to the visible-spectrum eyes, maybe the data they pick up could be used to add to a visual image?
I think your question (What wavelengths of electromagnetic radiation can your con-species perceive and focus into an image?) may be a little too homocentric for me to offer an answer beyond "none that I know of". We know from our own subjective experience that sight and heat are separate 'senses', though they're in fact the same thing at different frequencies. Sight is probably perceived as an 'image' by us because the organs that collect those frequencies are highly localised to one part of the body, and processed in specific parts of the brain, whereas the perceptors for heat frequencies are distributed across the entire skin, thus we perceive it as a 'feeling'. So creatures that have a much wider distribution of light receptors across their body might model changes in the visual spectrum as a feeling rather than as images.
You mention pit vipers. I wonder if the positioning of their pit organ (between the eyes and nostrils) acts as a 'third eye', adding to the visual images their eyes create - effectively an additional 'colour'? Maybe some brave scientist has already done the work to see if the brain circuits for the eyes and the pit organ interact/overlap, in which case the answer would probably be: yes.
The parietal eyes of a few vertebrate species can detect light radiation, but don't make use of rods and cones. I've no idea how data from these organs are interpreted alongside the more image-like information from the regular eyes. Given their connection to a specific part of the brain separate from the visual regions I suspect it might be as a separate sense rather than being integrated into the image. (I do know that the main effect of my pineal gland on me is to tell me when I'm tired - a feeling rather than an image.)
Electric eels detect EM at around 25Hz through perceptors distributed through their skin - so probably another feeling: two different types of heat? If you add in the pressure sensors in the lateral line that would make 3 different sources of information (4 including sound waves), like cones - I wonder if electric eels can 'visualise' their surroundings like we (or cows with their all-round sight) see it?
Conbiologically, I quite like the idea of having an animal perceive/use radio waves - it shouldn't be too difficult to explain/develop as radio waves work by inducing an electric current in a metal wire. Heck, if the real world can come up with electric eels, then why not this? If the radio wave receptors were limited to, say, the microwave range (1-2mm) in antenna close to the visible-spectrum eyes, maybe the data they pick up could be used to add to a visual image?
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- cuneiform
- Posts: 92
- Joined: 12 Aug 2010 05:54
Re: Color perception of your con-species
I think I saw recently that some group of scientists had found that the heat receptors in pit vipers are wired to the area for vision in their brain.
Here. It's a couple paragraphs down. It doesn't say that these two senses are overlapped, but at the least they are closely associated.
Here. It's a couple paragraphs down. It doesn't say that these two senses are overlapped, but at the least they are closely associated.
- eldin raigmore
- korean
- Posts: 6353
- Joined: 14 Aug 2010 19:38
- Location: SouthEast Michigan
Re: Color perception of your con-species
All good answers so far.
http://www.physorg.com/news76249412.htmlThanks, clockworkbanana.
@Micamo, that looks pretty well thought-out along the lines of what I was hoping I was asking.
I think animals with compound eyes, such as insects, do in fact have imaging ability. In case they don't, well, I didn't intend to leave them out, but it might be better to modify "my questionnaire" to include that as an additional question, than to modify the existing question to include them.
I did intend to leave out the kind of EM radiation that can be seen only once per eye because it would ruin the eye. I also intended to leave out, at least in that one question, pit vipers' pits, because they don't form images via living lenses. It's nevertheless a very interesting kind of sense, and I'd like to include a question that would cover it. They have to have "software" that processes what they get into an image-like something, or into data they can use as if it were an image.
Humans can, of course, detect ultraviolet light on our skins; at least, white people can, by being stupid on the beach in the summer and not wearing any sunscreen. That's not what I meant either. I meant something that one can sense rather quickishly and react to rather soonishly. By the time someone realizes they're sunburnt it's too late to do much about it.
Electric eels' electro sense isn't an "EM radiation" sense, is it? It's a sense for an electric field, right? Similarly the sense of the Earth's magnetic field that some birds and fishes are supposed to have, isn't an "EM radiation" sense. "EM radiation" means light-like radiation, from gamma rays through X-rays through ultraviolet through visible light through infrared through radio waves.
But many species use sound for "imaging", or at least, effectively for imaging, maybe as pit vipers use the input to their pit-organs. That's also be interesting; as would anything similar an electric-eel-like sense could be used for.
I once read an SF story about species living on a body with nearly no atmosphere and with an ambient temperature close to the boiling point of many of their nutrients. They had a "sight -- smell" like sense; they had chemoreceptors (like smell- and taste- -organs) as the "retina" of an organ like a pit-viper's pit (or like an eye, for that matter), shaped rather like a pinhole camera. The molecules they "smelled" tended to travel in straight (or, practically, straight-ish) lines, so this arrangement worked for them.
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I guess the questions I asked in the first post were only some of the questions I'd actually like discussed. But I still think they're the main ones.
What EM radiation wavelengths/frequencies can your species sense? That may have all kinds of answers.
What EM radiation wavelengths/frequencies can your species see by?
I still think shorter than 200 nanometers is unlikely, at least if their atmosphere is like Earth's.
I still think longer than 740 or 780 nanometers is unlikely if they're warm-blooded. Vertebrate's ears can't hear sounds that would be drowned out by the sounds our blood makes in our ears. Warm-blooded animals can't see by wavelengths actully emitted by their own eyeballs.
And I still think longer than 1400 or 1450 nanometers is unlikely if their lenses contain water.
An over-all sense of light, say, "feeling" specific wavelengths of "light" all over the skin, would not be good enough to form an image. It's not just that an image is sensed in a particular small part of the body; it's that if one can form an image, one can tell which direction which parts of the scene are coming from, to a very fine distinction of directions.
With a "whole-skin retina", though, the discrimination of which direction which parts of the received radiation were coming from, would be no finer than maybe 180 or 120 or 90 degrees or something like that.
That'd be great for letting you know that there's something you need to turn around and look at! It even gives you a strong hint which direction to look.
But it's not really helpful for figuring out what it is, what it's shaped like, and exactly where it is.
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The other thing I was asking about was, how well can they tell these wavelengths/frequencies apart?
http://www.physorg.com/news76249412.htmlThanks, clockworkbanana.
@Micamo, that looks pretty well thought-out along the lines of what I was hoping I was asking.
Maybe so; or at least it might be too sight-centric.Rik wrote:I think your question (What wavelengths of electromagnetic radiation can your con-species perceive and focus into an image?) may be a little too homocentric for me to offer an answer beyond "none that I know of".
I think animals with compound eyes, such as insects, do in fact have imaging ability. In case they don't, well, I didn't intend to leave them out, but it might be better to modify "my questionnaire" to include that as an additional question, than to modify the existing question to include them.
I did intend to leave out the kind of EM radiation that can be seen only once per eye because it would ruin the eye. I also intended to leave out, at least in that one question, pit vipers' pits, because they don't form images via living lenses. It's nevertheless a very interesting kind of sense, and I'd like to include a question that would cover it. They have to have "software" that processes what they get into an image-like something, or into data they can use as if it were an image.
Humans can, of course, detect ultraviolet light on our skins; at least, white people can, by being stupid on the beach in the summer and not wearing any sunscreen. That's not what I meant either. I meant something that one can sense rather quickishly and react to rather soonishly. By the time someone realizes they're sunburnt it's too late to do much about it.
Electric eels' electro sense isn't an "EM radiation" sense, is it? It's a sense for an electric field, right? Similarly the sense of the Earth's magnetic field that some birds and fishes are supposed to have, isn't an "EM radiation" sense. "EM radiation" means light-like radiation, from gamma rays through X-rays through ultraviolet through visible light through infrared through radio waves.
But many species use sound for "imaging", or at least, effectively for imaging, maybe as pit vipers use the input to their pit-organs. That's also be interesting; as would anything similar an electric-eel-like sense could be used for.
I once read an SF story about species living on a body with nearly no atmosphere and with an ambient temperature close to the boiling point of many of their nutrients. They had a "sight -- smell" like sense; they had chemoreceptors (like smell- and taste- -organs) as the "retina" of an organ like a pit-viper's pit (or like an eye, for that matter), shaped rather like a pinhole camera. The molecules they "smelled" tended to travel in straight (or, practically, straight-ish) lines, so this arrangement worked for them.
-----------------------------------------------
I guess the questions I asked in the first post were only some of the questions I'd actually like discussed. But I still think they're the main ones.
What EM radiation wavelengths/frequencies can your species sense? That may have all kinds of answers.
What EM radiation wavelengths/frequencies can your species see by?
I still think shorter than 200 nanometers is unlikely, at least if their atmosphere is like Earth's.
I still think longer than 740 or 780 nanometers is unlikely if they're warm-blooded. Vertebrate's ears can't hear sounds that would be drowned out by the sounds our blood makes in our ears. Warm-blooded animals can't see by wavelengths actully emitted by their own eyeballs.
And I still think longer than 1400 or 1450 nanometers is unlikely if their lenses contain water.
An over-all sense of light, say, "feeling" specific wavelengths of "light" all over the skin, would not be good enough to form an image. It's not just that an image is sensed in a particular small part of the body; it's that if one can form an image, one can tell which direction which parts of the scene are coming from, to a very fine distinction of directions.
With a "whole-skin retina", though, the discrimination of which direction which parts of the received radiation were coming from, would be no finer than maybe 180 or 120 or 90 degrees or something like that.
That'd be great for letting you know that there's something you need to turn around and look at! It even gives you a strong hint which direction to look.
But it's not really helpful for figuring out what it is, what it's shaped like, and exactly where it is.
-----------------------------------------------
The other thing I was asking about was, how well can they tell these wavelengths/frequencies apart?
My minicity is http://gonabebig1day.myminicity.com/xml
Re: Color perception of your con-species
I'm not sure yet whether I want to have the oil droplets, I'm having trouble finding information on exactly what they do for color perception.
- eldin raigmore
- korean
- Posts: 6353
- Joined: 14 Aug 2010 19:38
- Location: SouthEast Michigan
Re: Color perception of your con-species
See e.g.Micamo wrote:I'm not sure yet whether I want to have the oil droplets, I'm having trouble finding information on exactly what they do for color perception.
http://www.webexhibits.org/causesofcolor/17B.html
http://en.wikipedia.org/wiki/Color_perc ... er_animals
http://users.mis.net/~pthrush/lighting/cvb.html
http://www.ncbi.nlm.nih.gov/pubmed/8351832
http://www.wordiq.com/definition/Color_ ... perception
http://www.ncbi.nlm.nih.gov/pubmed/9839454
http://facweb.cs.depaul.edu/sgrais/color_perception.htm
http://psychology.wikia.com/wiki/Color_perception
My minicity is http://gonabebig1day.myminicity.com/xml
- eldin raigmore
- korean
- Posts: 6353
- Joined: 14 Aug 2010 19:38
- Location: SouthEast Michigan
Re: Color perception of your con-species
They help the perceiver distinguish between different mixes of wavelengths.Micamo wrote:I'm not sure yet whether I want to have the oil droplets, I'm having trouble finding information on exactly what they do for color perception.
For instance, suppose you have two photo-reactive photo-sensitive visual pigments, VP500 and VP600.
Suppose VP500 reacts at:
100% to wavelength 500 nm,
Spoiler:
Spoiler:
Similarly, suppose VP600 reacts at:
100% to wavelength 600 nm,
Spoiler:
Spoiler:
If the only chromoceptors stimulated by wavelengths between 500nm and 600nm are VP500 and VP600, then the light at any single wavelength between 500nm and 600nm can be mimicked by a mixture of light at 500nm with light at 600nm.
For instance,
100 photons at 550 nm could be mimicked by 75 photons at 500nm with 75 photons at 600nm;
because light at 550nm makes both the VP500 cones and the VP600 cones respond at 75%.
For more instances,
Spoiler:
Suppose OD500 lets through;
0% of the light at a wavelength of 500nm,
Spoiler:
Spoiler:
Similarly, suppose OD600 lets through;
0% of the light at a wavelength of 600nm,
Spoiler:
Spoiler:
Now suppose you have four types of cones that respond to wavelengths of 500nm to 600nm, instead of only two:
VP500 cones without oil-droplets,
VP500 cones with OD600 oil-droplets,
VP600 cones without oil-droplets,
and VP600 cones with OD500 oil-droplets.
Now, light at 550nm makes the VP500-without-oil cones and the VP600-without-oil cones both respond at 75%; but the VP500-with-OD600 cones and the VP600-with-OD500 cones both respond at 18.75% (about 19%).
Light at a wavelength of 500nm always equally stimulates the VP500-without-oil cones and the VP500-with-OD600 cones equally, and always fails to stimulate both the VP600-without-oil cones and the VP600-with-OD500 cones.
Likewise, light at a wavelength of 600nm always equally stimulates the VP600-without-oil cones and the VP600-with-OD500 cones equally, and always fails to stimulate both the VP500-without-oil cones and the VP500-with-OD600 cones.
So any mix of wavelength-500nm light with wavelength-600nm light will get the same reaction from the VP500 cones whether or not they have an oil-droplet, and will get the same reaction from the VP600 cones whether or not they have an oil-droplet.
No single-wavelength light in the range of 500nm to 600nm can be mimicked by any mixture of two other wavelengths in that range.
Apparently many birds who have cones with oil-droplets need to be able to differentiate "colors" in the oranges-and-yellows better than cones without oil-droplets would enable them to do. In particular they sometimes need to be able to tell the difference between, on the one hand, a mix of two wavelengths, and, on the other hand, a single wavelength, when without the oil-droplets they couldn't do that.
_______________________________________________________________________________
Suppose you had visual pigments VP200, VP300, VP400, VP500, VP600, and VP700.
Suppose:
Spoiler:
If, between the peak-response wavelengths of any two visual pigments, one finds a range of wavelengths to which only those two pigments respond, then any single wavelength in the interior of that range can be imitated by a mix of two other wavelengths in that range, and any mix of any two wavelengths in that range can be mimicked by some single wavelength in that range.
But if we had oil-droplets OD200, OD300, OD400, OD500, OD600, and OD700, such that:
Spoiler:
Spoiler:
Spoiler:
Similarly, because OD700 is transparent to wavelengths 600nm and shorter its presence or absence makes no difference to the response of the VP600-bearing cones to light in the 450-to-550nm range, provided those cones don't have the OD500 droplets.
So let's look at some wavelengths.
Suppose we represent the responses by ordered 7-tuplets of percentages of peak response, in the order
Spoiler:
460nm gets (12%, 60%, 80%, 80%, 32%, 0%, 0%)
480nm gets (3%, 30%, 90%, 90%, 63%, 0%, 0%)
500nm gets (0%, 0%, 100%, 100%, 100%, 0%, 0%)
520nm gets (0%, 0%, 63%, 90%, 90%, 30%, 3%)
540nm gets (0%, 0%, 32%, 80%, 80%, 60%, 12%)
550nm gets (0%, 0%, 19%, 75%, 75%, 75%, 19%)
No linear combination of 450nm and 500nm and 550nm, can add up to mimicking any of 460nm, 480nm, 520nm, or 540nm.
Spoiler:
My minicity is http://gonabebig1day.myminicity.com/xml
Re: Color perception of your con-species
Wow! That was a really helpful explanation. You're so awesome!In particular they sometimes need to be able to tell the difference between, on the one hand, a mix of two wavelengths, and, on the other hand, a single wavelength, when without the oil-droplets they couldn't do that.
Re: Color perception of your con-species
Eldin, can you explain that in a few simple words?eldin raigmore wrote:They help the perceiver distinguish between different mixes of wavelengths.Micamo wrote:I'm not sure yet whether I want to have the oil droplets, I'm having trouble finding information on exactly what they do for color perception.
For instance, suppose you have two photo-reactive photo-sensitive visual pigments, VP500 and VP600.
Suppose VP500 reacts at:
100% to wavelength 500 nm,75% to wavelengths 550 nm or 450 nm,Spoiler:0% to wavelengths 600 nm or longer or 400 nm or shorter.Spoiler:
Similarly, suppose VP600 reacts at:
100% to wavelength 600 nm,75% to wavelengths 650 nm or 550 nm,Spoiler:0% to wavelengths 700 nm or longer or 500 nm or shorter.Spoiler:
If the only chromoceptors stimulated by wavelengths between 500nm and 600nm are VP500 and VP600, then the light at any single wavelength between 500nm and 600nm can be mimicked by a mixture of light at 500nm with light at 600nm.
For instance,
100 photons at 550 nm could be mimicked by 75 photons at 500nm with 75 photons at 600nm;
because light at 550nm makes both the VP500 cones and the VP600 cones respond at 75%.
For more instances,But now, suppose you also had differentially-opaque/differentially-transparent droplets of oils, OD500 and OD600.Spoiler:
Suppose OD500 lets through;
0% of the light at a wavelength of 500nm,25% of the light at wavelengths of 550nm and 450 nm,Spoiler:100% of the light at wavelengths of 600nm or longer and 400 nm or shorter.Spoiler:
Similarly, suppose OD600 lets through;
0% of the light at a wavelength of 600nm,25% of the light at wavelengths of 650nm and 550 nm,Spoiler:100% of the light at wavelengths of 700nm or longer and 500 nm or shorter.Spoiler:
Now suppose you have four types of cones that respond to wavelengths of 500nm to 600nm, instead of only two:
VP500 cones without oil-droplets,
VP500 cones with OD600 oil-droplets,
VP600 cones without oil-droplets,
and VP600 cones with OD500 oil-droplets.
Now, light at 550nm makes the VP500-without-oil cones and the VP600-without-oil cones both respond at 75%; but the VP500-with-OD600 cones and the VP600-with-OD500 cones both respond at 18.75% (about 19%).
Light at a wavelength of 500nm always equally stimulates the VP500-without-oil cones and the VP500-with-OD600 cones equally, and always fails to stimulate both the VP600-without-oil cones and the VP600-with-OD500 cones.
Likewise, light at a wavelength of 600nm always equally stimulates the VP600-without-oil cones and the VP600-with-OD500 cones equally, and always fails to stimulate both the VP500-without-oil cones and the VP500-with-OD600 cones.
So any mix of wavelength-500nm light with wavelength-600nm light will get the same reaction from the VP500 cones whether or not they have an oil-droplet, and will get the same reaction from the VP600 cones whether or not they have an oil-droplet.
No single-wavelength light in the range of 500nm to 600nm can be mimicked by any mixture of two other wavelengths in that range.
Apparently many birds who have cones with oil-droplets need to be able to differentiate "colors" in the oranges-and-yellows better than cones without oil-droplets would enable them to do. In particular they sometimes need to be able to tell the difference between, on the one hand, a mix of two wavelengths, and, on the other hand, a single wavelength, when without the oil-droplets they couldn't do that.
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Suppose you had visual pigments VP200, VP300, VP400, VP500, VP600, and VP700.
Suppose:If there are no oil-droplets, the VP400 cones by themselves can't tell the difference between wavelength 350nm light and wavelength 450nm light; VP400 cones respond at 75% to both of those wavelengths. But 450nm light stimulates the VP500 cones too, whereas 350nm light does not.Spoiler:
If, between the peak-response wavelengths of any two visual pigments, one finds a range of wavelengths to which only those two pigments respond, then any single wavelength in the interior of that range can be imitated by a mix of two other wavelengths in that range, and any mix of any two wavelengths in that range can be mimicked by some single wavelength in that range.
But if we had oil-droplets OD200, OD300, OD400, OD500, OD600, and OD700, such that:Now, in addition to each visual pigment without any oil-drops, we could also have:Spoiler:For instance, the cones that respond to light in wavelengths between 450nm and 550nm are:Spoiler:Because OD300 is transparent to wavelengths 400nm and longer its presence or absence makes no difference to the response of the VP400-bearing cones to light in the 450nm-to-550nm range, provided those cones don't have the OD500 droplets.Spoiler:
Similarly, because OD700 is transparent to wavelengths 600nm and shorter its presence or absence makes no difference to the response of the VP600-bearing cones to light in the 450-to-550nm range, provided those cones don't have the OD500 droplets.
So let's look at some wavelengths.
Suppose we represent the responses by ordered 7-tuplets of percentages of peak response, in the order450nm gets (19%, 75%, 75%, 75%, 19%, 0%, 0%)Spoiler:
460nm gets (12%, 60%, 80%, 80%, 32%, 0%, 0%)
480nm gets (3%, 30%, 90%, 90%, 63%, 0%, 0%)
500nm gets (0%, 0%, 100%, 100%, 100%, 0%, 0%)
520nm gets (0%, 0%, 63%, 90%, 90%, 30%, 3%)
540nm gets (0%, 0%, 32%, 80%, 80%, 60%, 12%)
550nm gets (0%, 0%, 19%, 75%, 75%, 75%, 19%)
No linear combination of 450nm and 500nm and 550nm, can add up to mimicking any of 460nm, 480nm, 520nm, or 540nm.
Spoiler:
My neurochemistry has fucked my impulse control, now I'm diagnosed OOD = oppositional opinion disorder, one of the most deadly diseases in totalitarian states, but can be cured in the free world.
- eldin raigmore
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Re: Color perception of your con-species
Probably could, by leaving out most of the words in my previous post; but I don't know exactly which ones to leave out, and expect I'd have trouble deciding.Tanni wrote:Eldin, can you explain that in a few simple words?
Since Micamo understands what I said, maybe Micamo can rephrase it in shorter and/or simpler form?
@Micamo; care to give it a try?
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Re: Color perception of your con-species
Basically the oil droplets change the cone response function to no longer be "linear." In humans, photons with different wavelengths can be mistaken for photons of a single wavelength, where the "blended" color is a sort of average of the different wavelengths. The oil droplets make it so the creature can differentiate between, e.g., 400 nm + 500 nm and 450 nm.
- Ear of the Sphinx
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Re: Color perception of your con-species
Yhm.Basically the oil droplets change the cone response function to no longer be "linear." In humans, photons with different wavelengths can be mistaken for photons of a single wavelength, where the "blended" color is a sort of average of the different wavelengths. The oil droplets make it so the creature can differentiate between, e.g., 400 nm + 500 nm and 450 nm.
In other words, we see RGB. Yellow is a mixture of red and green for us, so we can replace yellow with red-green e.g. in construction of screens. If there was a creature seeing in RYGB, it would see yellow and red-green different, as we see green and red-blue different.
But that's possible there are humans that can see four basic colours. And there are some RYGB screens produced.
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Re: Color perception of your con-species
It would be cool to be a tetrachromat...
I wonder if that is another reason birds can see small animals from a distance... by discerning color differences that humans and other animals cannot.
I wonder if that is another reason birds can see small animals from a distance... by discerning color differences that humans and other animals cannot.
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