My spouse is a tetrachromat, and it's fascinating. Sometimes she sees patterns on leafs or bird feathers that other people don't see. Sometimes she can detect a very minor difference in colors of clothing items that other people see as identical. If a person wears those two items of clothing together she finds it really irritating.
She also sometimes see colors in her dreams that are outside of a pallet humans see in real life, but after she wakes up she can't describe them. It's not one color or one hue, there are several colors that she can only experience in her dreams.
> She also sometimes see colors in her dreams that are outside of a pallet humans see in real life, but after she wakes up she can't describe them. It's not one color or one hue, there are several colors that she can only experience in her dreams.
Sounds like she is describing imaginary or impossible colors.
That whole article is flawed in defining 'color' as 'color perception of average human'. I don't think one gets anywhere unless one strictly separates the physical properties (of a light source) from the perception (of a (human or otherwise) sensor).
With psychedelics, I saw colors that I'd never seen in reality. But that's just color illusion on steroids.
What interesting, though, is that I saw patterns in objects that normally seemed ~uniform in color. So maybe "software tweaks" can mitigate hardware limitations.
Somewhat? I wonder how you would measure that. Many long years ago a co-worker was explaining a control panel to me. It had red and green LED indicators. He had them backward as he pointed them out. I asked him if he was color-blind. His reply was "Yes, a little bit."
It seems to me that when everything looks the same from birth on (excepting perhaps focus. ;) ) then it is difficult to compare what one sees with what others see.
I also wonder if some colored LEDs tend to be "worst case" as they may be monochromatic and if the eye is not sensitive to that particular wavelength, it will not be visible as color.
Actually... I also wonder about how a wide gamut of colors can be represented by relative intensity of three primary colors: red, green and blue. I would expect the emitters in, for example, an LCD screen to emit light at specific frequencies. How can any combination of three frequencies represent what must be a broad rage of frequencies that form any given color in the world around us.
How colorblind you are -- or maybe in what way -- determines which color combinations you can distinguish characters for. That's horrible, I know, but I'm tired.
I suppose it depends on what mutation(s) you carry. And probably other factors that affect penetrance.
I think the tests provide an objective measure of color blindness (or maybe better described as color acuity.) I was more interested in the subjective experience. How can someone know what they're missing if they have never experienced it.
Interesting. I didn't know that red/green color blindness could be partial. In the case I cited, the person was completely unable to distinguish red/green LEDs so I assumed his condition was complete, but perhaps it was just the specific wavelengths involved that were troublesome for him.
That aspect of things that is caused by differing qualities of the light reflected or emitted by them, definable in terms of the observer or of the light
That is, colour is a perception, dependent on the observer. Agreed-on colours being those on which typical observers share common experience, is correct.
Wavelengths, pigmentation, and diffraction effects (which give rise to colour in observers) are phenomena.
The terms quale and qualia suggested by @codebolt are indeed quite useful.
(Language itself is shared agreement among symbolic references, given context.)
The term quale/qualia is useful in this discussion. It seems his wife is experiencing color-qualia in her dream that doesn't correspond to any qualia that is produced in response to light hitting her eyes, whatever the wavelength. To me it only highlights our gaping lack of scientific understanding as to what qualia is and how it is produced.
I don't see why seeing an extended pallet in dreams would be a thing particular to tetrachromats. Unless trichromatic vision completely covers the gamut of naturally occuring wavelength combinations, which I doubt.
Colors like magenta (red and blue wavelengths together) are nonspectral, having no single wavelength they correspond to. They only exist as a mix, and we see a pinkish color that you can't write down as a wavelength.
Tetrachromats could plausibly see more nonspectral colors by activating their extra color receptor and one of the other ones. There would be no exact equivalent in trichromatic vision.
It depends on what their brains decide to do with it- maybe they would just land on an existing color in between. But there's no reason it has to.
So these colors are something that tetrachromats could maybe see while awake, but usually with lots of other colors mixed in. Asleep, maybe the brain starts to play with them and generates pure versions of them. Trichromats wouldn't be very likely to have these dreams because their brains don't have experience of tetrachromat nonspectral colors at all.
Ah! Now I have theory: We trichromats have a hue circle, and magenta is the point where the lower and higher wavelenghts are joined. However this simple model breaks down for tetrachromats. Perhaps they have two hue circles orthogonal to each other. This means, hue becomes two-dimensional. Really crazy to imagine such a thing.
I imagine in school the teacher tells the poor girl: Mix the blue and yellow colors to get green, and the girl doesn't understand because she has a lot more complex color model than the teacher.
We see magenta as a separate color because we can distinguish it from green- it's not green, because Red and Blue don't activate our green cones. But we can't distinguish between spectral yellow and R+G because there's no yellow cone: the activations of all our cones are more or less identical in both cases.
If you have a yellow cone, you'd conceivably be able to distinguish between both kinds of yellow: redgreen and yellow could look as different as green and redblue do. I'm not sure how that would look as a "wheel", perhaps a figure-eight with the crossing at yellow.
I think this is a very good explanation. You're emphasizing that a trichromat will experience the same activation of their cones to the wavelength of yellow light, and light containing the wavelengths of red and green mixed. So the spectra of these two colors will be different, but appear identical.
Whereas a hypothetical tetrachromat with an additional cone type that activates to the yellow wavelength, will have obviously different activations of their cones for the "wavelength of yellow" and "wavelengths of red and green mixed". And hence experience them as different colors.
I'm not familiar enough with the different definitions of color spaces to define how to model this. You could easily define it as a four-dimensional RGBY color space, but to my understanding the other color spaces are defined because they have better properties for combining different colors, or playing better with interpolation between colors.
It would be a challenge to come up with a good four-dimensional color space that is a useful artistic and visual tool, given that there are very few people around to evaluate it! And also because all computer monitors are trichromatic, so it'd be a job in itself to set up a test system.
I wish someone in the interview had asked some of these people how they experience photos on computers!
You can arrange the three colors in a triangle, which defines a plane, is treated like a circle in color theory, and looks like a weird stretched out "U" when put in a perceptually uniform space (stretched towards green, which we see best, and flat on the magenta side). Perceptual color spaces combine this with luminance, which is sensed by rods instead of cones.
Tetrachromatic colors could be placed in a tetrahedron, defining a space and being approximated as a sphere. A perceptually uniform representation would probably be curved on the three edges that agree with the spectrum and flat on the three that don't. Green is still probably the biggest. Then you'd add luminance as a fourth dimension because it's still rods.
Interesting idea, however I think this is too simple. With three cones we have a three-dimensional space of color. We can express this space with RGB or HSV and so on, just by a three dimensional basis vector we can describe one color point in the color space.
With tetrachromats we get a four-dimensional space of color. So we need something like RGBX or a two-dimensional hue value like for example H1,H2,S,V. That's what I meant with a second hue circle orthogonal to the one we already know.
What we see as yellow is for the tetrachromat a whole second hue circle varying in the value of second hue.
An example: Yellow is a point on the first hue circle. For the tetrachromat these colors are different, but boring yellow for us:
- pure yellow
- mixture of red and green
- mixture of pure yellow, red and green
In other words, what we see as yellow is a whole dimension of different colors for tetrachromats.
They also would probably be able to distinguish yellow+blue from pure green.
Also, if you mix R+B, that's magenta, and if you start mixing in blue it will turn white or gray. But if you can see yellow, RYB would look different from R+a little g+B, which is what RYB would look for trichromats, I think.
I imagine in school the teacher tells the poor girl: Mix the blue and yellow colors to get green, and the girl doesn't understand because she has a lot more complex color model than the teacher.
This is honestly one of the saddest parts of human society. Some people, including those in positions of authority, either don't understand or outright reject the notion that different people perceive the world differently.
What you've described is why I (not a graduate of mathematics) never understood why the 'four colour theorem' is difficult to prove. I accept that it is, because it took so long and initially was only done computationally, but I don't understand it.
In secondary school I argued along the lines you describe, that you can mix three colours in a circle, and then a fourth around the circumference mixes only with at most two of the others - and in terms of the FCT is then a 'barrier' allowing re-use of the first three.
That's quite off-topic, but you suddenly jolted my memory of it. More on-topic, being colour-blind (never told which type and I can't work it out either) I find conversations about colours frustrating, and very strange to wonder if we see anything alike at all, or just learn to call the same physical thing alike despite perceiving it perhaps very differently.
The hard part in proving the four color theorem is proving that there aren't any possible maps that can't be colored with four colors. Perhaps there's one out there that needs five and can't be colored with only four.
Proving some maps can't be colored with three colors is easy, you only need to find one and enumerate all the three-colorings and find none of them work.
It's not really a theorem about colors though, they're just labels.
It's straightforward to prove that you can't have more than four plane regions that all mutually touch; K5 is a nonplanar graph. But you can construct maps (planar graphs) that have no K4 subgraphs that nevertheless have chromatic number 4. C5 plus an additional node connected to all 5 of its nodes, for example. The challenge is to show that the same thing can't happen with chromatic number 5. I think it does happen with chromatic numbers 6 and 7 on the surface of a torus (but you can also just map K7 onto a toroidal map.)
I recognize that this comment includes jargon, but I assume you'll Google it. I'd include diagrams but HN doesn't support them.
Thank you for giving me the terminology - I think I do see why it's hard mathematically, I just struggle to understand that graphically, it seems so obvious on paper - looking by cases at how many existing regions a necessarily new colour touches.
But, I understand and trust the mapping of the problem to a graph, so perhaps if I see why the problem is hard on a graph that should be enough for me.
But my reasoning was along the lines (but now in my newfound terminology) of:
K1 - trivially 1 colour needed. K2 - 2.
If we add another region on the map, we either have K3 or K1,2. In the latter case the third region/vertex need only be different to the one it touches, but K3 clearly needs 3 colours.
Adding the fourth region is similar, and again K4 clearly needs 4.
The fifth region touches at most 3 others, since K5 is non-planar. Thus, it can take the colour of the untouched region.
That's not very formal, but why isn't proof by induction easy from there? i.e. if we can't build a map that ever requires a fifth colour, then it can't be that there exists a map which requires more than four?
But why does it matter if I can tell you how to colour it,* isn't it sufficient to show that we can't construct one that can't be coloured in at most four, as I tried to outline above? Surely it must then be that any exercise is either 4-colourable, or non-planar/otherwise out of scope of the problem?
* It's easy starting from the end, just put one colour in the middle, then alternate second/third colours around the edge until you get back to the start and have to add a fourth. From construction, the worst case is from K1,2 then adding another for K1,3 at which point we need four colours already, but when we add two more on what will be the C5# around they each only connect to one each side and the center. In adding each one you can simply use the colour one hop over on the circumference.
# Since the center of K1,3 must be the center of the final C5-plus-thing, as it already had 3 spokes.
It's correct, as you say, that if we can't build a map that ever requires a fifth colour, then it can't be that there exists a map which requires more than four.
It's just that the C₅-plus-thing requires four colors, even though it doesn't contain any K₄ induced subgraphs. So we could imagine that there might be some larger planar graph that requires 5 colors without containing K₅. As it turns out, there isn't, but that's the thing that's hard to prove.
Hm, many thanks for the pointers. It's still not completely clear to me, but I have a much better idea and know the story of thing to search/read up on. Cheers.
That has nothing to do with my argument. Why would tetrachromats be inclined to dream of colors they do not see in the real world any more than trichromats?
My point is they would see those colors in the real world, but only in combination with other colors, so it wouldn't be that noticable. They wouldn't see pure versions of them much, if at all. The intensity in a dream might be much stronger, enough that it would seem like a qualitatively new color rather than "hmm, that blue has something different going on compared to other blues" they you might get in real life.
You could put them in front of light source that generated pure wavelengths designed to selectively activate their extra cone and ask what they see when you start mixing pure blue or green into it. Maybe they'd recognize those colors from their dreams, maybe not. I don't know. But it's a mechanism that would explain how tetrachromats might dream colors that trichromats don't.
But this assumes the gamut of trichromacy is more anchored in reality (woken life) than the gamut of tetrachromacy. In principle there is nothing different between a trichromat and a tetrachromat sense of color. They see one dimension of color more, just like humans see one dimension more than dogs.
The fourth cone in tetrachromats overlaps quite a lot with the other three (which is why most tetrachromats don't see more colors than trichromats). For people where the fourth cone is meaningfully distinguishable from the others, it doesn't seem weird to me that you wouldn't see many objects that are strongly activating just that extra cone and not the ones next to it (wavelength wise) because they're closer together.
We don't see bright, "pure" magenta very much, and when we do it's usually because we've engineered it. Nobody is engineering pigments for tetrachromats to enjoy.
If I'm right, people who are nearly (but not entirely) colorblind (anomalous trichromats) due to a shifted cone would likewise be able to dream in colors they are capable of seeing only dimly while awake, whereas dichromats wouldn't.
That’s why I said naturally occurring. If naturally occurring colors corresponds approximately 1-to-1 with trichromatic vision, that could explaining why a tetrachromat dreams of unreal colors and trichromats don’t.
That's not quite the right way to think about it. Obviously, existing vision "covers" the full spectrum, there aren't any wavelengths that we can't see.
The trick to impossible colors is recognizing that our existing receptor spectra overlap. It's not possible to get "100% red" in the sense of only the "red" cone cells firing and none of the "blue" or "green" ones, because those other cells are going to fire at some small rate for the same frequencies.
But our brain can certainly receive such a color even if our eyes don't produce it, so in some sense we "understand" it as a color even if we'll never see it outside a laboratory or hallucination.
I think you and the other person are referring to two different "spectrums". Our vision covers a tiny portion of the EM spectrum, for instance, we can't see infrared, microwave, gamma, x-ray, etc.
There are separately colors which we are wired to hypothetically receive, as you point out (and I find interesting) - IE, if you replace the eye with some sort of artificial replacement, then such a signal could get received by the brain, but with the current sensors it is impossible (also, I suppose a colorblind person could receive such a signal as 100% red without the other colors).
There's also the possibility during a dream of creating objects or sensations that are not physically possible. For instance, I've had dreams where I had a form of telekinesis, and obviously there's no sort of brain wiring to manipulate physical objects outside of the normal motor functions. Still, it made sense in the dream - and it's not like I could describe how I did it, and it's not because the hardware exists but the sensor doesn't.
Although - you could argue that there's a layer of abstraction in the brain of such things in the brain - for instance, when I'm typing these words I don't actually ever have any conscious awareness of my finger motions. I don't even think about the act of typing at all; only the words. So, thinking about it, the brain does have an idea of manipulating objects outside of a need for muscles to do it.
I would think for a tetrachromat the abstract sensation of seeing colors you can't describe to others is itself a familiar one, and that feeling itself is something you might encounter in dreams. My dreams tend to start with a feeling, and then build a context for it.
probably because exposure to the sensory information is required to be reproduced in dreams. People who are born deaf don't hear sounds in dreams either.
I have the opposite thing. Where I can only perceive 1/10th the colours most people can. Mostly that results in people recoiling in shock when I candidly describe something as blue when it is in fact purple. Or orange when it's yellow. Or something else that's very, very bordeline in-between two colours.
Strange to think there are people who can perceive two orders of magnitude more colour than me. Damn.
When I take psychedelic drugs, I can see colours that are not part of my normal tritanomolous vision, and are impossible to adequately describe. I understand this is quite a common experience.
Maybe those colours are what I would see if I had properly functioning cones, or even a fourth cone variant. Or maybe they're just a symptom of wider brain dysfunction due to the psychedelic drugs. Hard to know...
I sometimes slip into a kind of lucid state with intense unnatural colors and extreme fractal geometries. It's quite fun, and fades away in less than a minute. It is definitely related to psychedelic vision and the colors in tibettan art. I have in rare cases been able to access it with sober meditation.
Being colorblind myself, I used to be envious of people who could see more colors than me. I still am, to some extent. Though, over the years I picked up on an upside to it. Since I'm unable to see as many colors when viewing the world, I tend to pick up changes in motion much more quickly than people around me.
It makes me fairly proficient at driving, dodging moving obstacles while doing any physical activiy, and fast-paced games (like FPS) - even if the trade off is that I occasionally killed teammates because I couldn't see the color differences between players at times.
I've heard (it could be total BS) that color deficient snipers have an advantage because they can spot artificial camo more easily. It makes sense if you're used to not relying on color as much and look more for patterns and motion
I'm also colorblind, and other than the occasional mixup, I don't feel like I'm missing out on much. There's still plenty of color, perhaps just with less vibrant difference in the red-green area.
I was referring to driving a vehicle IRL - just in case that wasn't clear. Some gimmes: brake lights are usually horizontal to one another, and red. If you're driving towards bright white lights, or they are vertically aligned, something has probably gone wrong...
This type of pattern matching is frequently how I go about navigating the world.
Like the other commenter I too am partially colorblind. I don't know how my exact condition is called, but it's very minor. In those online tests with many-many reddish, greenish and yellowish dots I fail to read the symbol or a number in about 1-2 cases out of 20. So, in real world I can see most reds and greens, and it's not a big deal for me. However, due to my condition and her abilities our differences in color perception come up a lot more often than one might think. Surprisingly, we found out about it after about 2 years of being together :D
Of course I envy her, but I mostly just happy that she can experience some aspects of our world better than most other people. It's like with talents: the fact that someone has a particular talent or skill that you lack doesn't make you hate this person. Instead you ask them to show it off, they do, you "Oo-ooh!" and "Aa-aah!", they feel really good about themselves and you're both happy.
Sometimes she is sad I can't appreciate something she sees, but we don't dwell on it. She would often describe the shape or a pattern she sees and I try to picture it and say something like "Oh that's neat!".
Also, there are some clothing items I never combine, and I always ask her for advice when I select my cloths, or colors for my presentation or charts.
Colors are very cool. I wish we could have some kind of tech that would allow us to see colors like some birds or aquatic species do. These days there are glasses for colorblind people to give them some extended color perception, so the tech is making some baby steps.
Have you read about how those glasses work? It's kind of cool.
It turns out that many color-blind people have the normal distribution of cones, but the spectral response is similar enough that the brain can't differentiate. By putting an optical notch filter in the overlap region, the difference is accentuated and the brain starts picking it up normally.
I think envy is instinctual in gregarious animals. It's a mechanism for social balancing. You can't stop the feeling except to be at the top of the social hierarchy. You can control your behavior when you feel it though.
You can practice by surrounding yourself with people better than you. Play games with people better than you. Find mentors.
Grow as a person so you love yourself rather than envy others. Recognize that almost everyone has something you don't. Better than you at something.
Reflect on the great things about yourself. Remember who you are. Where you started.
Be good. Be true to yourself. Develop your moral code. Treat all with respect and love. Including you with all your imperfections.
I don't know about andrewl-hn's spouse, but in general, there is a way. From the article:
But by 2010, [Jordan] had found a subject who perfectly acted the part of a tetrachromat. Jordan’s “acid test” involved coloured discs showing different mixtures of pigment, such as a green made of yellow and blue. The mixtures were too subtle for most people to notice: almost all people would see the same shade of olive green, but each combination should give out a subtly different spectrum of light that would be perceptible to someone with a fourth cone. Sure enough, Jordan’s subject was able to differentiate between the different mixtures each time. “When you ask them to discriminate between the two mixtures, a tetrachromat can do it very quickly. They don’t hesitate,” says Jordan.
Science has a method for cutting through speculation - in this case, it is a variant of the Ishihara test.
Yeah, I don't doubt that there are scientific methods to confirm this, I was interested specifically in how the parent commenter knew (maybe she was tested). I mean there are people who see things that aren't there too... I guess HN didn't appreciate my question. :-/
I did not think it was an unreasonable question. The article also mentions that quite a few of the people who thought they had this ability were unable to demonstrate it through this sort of test. As a certain percentage of the population think they have a given disease when they do not, I would not be surprised if a certain percentage, on hearing about tetrachromacy, would think they have it for less than rigorously sound reasons.
Before asking this very dismissive question, did you pause to think about how you might design an experiment to determine a rough count of how many colors people can discriminate between? Because it took me all of 30 seconds to do so, and I'm just a graph theorist. I don't know shit about anatomy or color spaces.
I'd use a 2-panel diagram. On each round, the panels are assigned random colors. The subject is asked "are the panels same, or different?" Some proportion of the time, they're identical. If they just mash "different" every time, you'll see that in the data and you'd reject those subjects -- or accumulate those false guesses into an uncertainty measure. If they hit 'same' on different colors... make a graph with edges between those colors. Some time after the graph is connected, try and find a minimum vertex cover. The order if that vertex cover should be a reasonable estimate of the number of colors a person can see.
It seems like this one is really easy to test, like via the clothing example the top comment mentioned -- just see if the person can reliably differentiate between them
There's actually a way for us to experience something similar: wear eyeglasses where the two lenses have different spectra. Then these "extra colors" show up as a shimmering sensation.
I have such a pair, but have to say it's not very exciting; there's not that much metamerism in the real world.
This is a really good idea. In fact it should be able to promote trichromats to hexachromats, since we have two eyes. I wonder if we could calculate optimal filters, sort of like EnChroma (enchroma.com) for trichromats.
Where did you get your pair? What filters did they have?
Oh, they're not commercially available. My dad negotiated with an optical filter manufacturing company to make prototypes because I was interested in commercializing the idea. If you were going to do something similar today, very likely your best bet would be to get one side as EnChroma and the other as a neutral density filter (or a tint matching the EnChroma).
Maybe if this group grows over time we can finally move past the 24-bit color space that the mainstream has been stuck with for decades. I'm not a tetrachromat nor a woman, but I do routinely find myself bothered by the banding of gradients in the 24-bit color space. I went as far as asking Mozilla to consider adding a dithering algorithm to their gradients [1].
This. Banding and tetrachromacy have absolutely nothing to do with each other. Something between 30- and 48-bit color will fix banding beyond anyone's perception.
The idea of accomodating tetrachromats is certainly quite interesting, but it doesn't appear they all have a fourth rod that responds to the same frequency distribution, so 4x8 would only work for individual people, not tetrachromats at large?
I don't think there's any need to go to four primaries. If you keep just RGB but have more bits per channel you can widen the color space without getting banding while also representing many more colors. You just move the RGB primaries out to cover more space. Doing 3x32bit float is common to get you all the color resolution you'll ever need for calculations in image pipelines.
We could even go up to 2x64bit floats for even more definition...
Wait, that didn't make sense to you as a trichromat?
Neither does your suggestion to a tetrachromat. For them color is a four dimensional space (tetrachromat literally means "four-colorist"). The RGB cube becomes a RXGB hypercube. You can't emulate X with RGB like you can't emulate green with red and blue.
That will heavily depend on if the extra primary actually allows you to sample something significantly different from the other three or just gives you more color differentiation. My understanding was that human tetrachromats had their extra primary close to one of the "standard" ones and that gave them more color differentiation but not exactly extra colors.
As someone who watches a lot of cartoons, I'm grateful. I'm also grateful for how smooth TV has gotten in the HD era. I was using a neural net to restore standard def TV and make it look like proper HD fooling people around me, but the frame rate difference due to deinterlacing is a giveaway.
It's a complex subject. Most NTSC interlacing is what you call 3:2 interlacing. When deinterlacing this kind of interlaced content, the best method is a 3:2 pulldown which converts the frames back to the original frames, or almost all of them, that is. There is a few frames lost in this process. Eg, 30fps interlaced then deinterlaced turns into 29.97 fps. 24 fps turns into 23.976 fps. This introduces a sort of stutter that true progressive content does not have.
Also, in the 90s most anime, for example, was 24 fps, where modern day anime is 30fps or higher. This difference is noticeable as well.
That's really interesting, thanks. Isn't it possible to fix the stutter by transforming the video into 60fps exactly with frame interpolation? Wouldn't that simulate what an old CRT would end up doing and look better? Or maybe just fudge the timestamps to go to 30fps as the very slight speedup will not be noticeable?
Probably bad deinterlacing somewhere along the way. For too long, half-rate deinterlacing (60i > 30p) has been common. That's starting to change with 60p support on major distribution platforms, but in the piracy scene half-rate deinterlacing is still common for many types of content.
My daughter has something like this. She can see colours nobody else can, but pays for it a little by not being able to see as much out of the corner of her eyes than most people.
One optician panicked so much at what she said they referred her to the hospital in case she was having a stroke! And that's when we discovered what she can do. I just thought she was good at picking clothes that went together well.
> I just thought she was good at picking clothes that went together well.
Good for her, but I doubt this is because she can "see colors nobody else can". If that was the case, she would most likely be worse at picking colors which (to the average eye) goes together well. Maybe she just have good taste?
How do you justify the idea she'd be worse at picking colors that go together?
If you pick points that are close together in four-dimensional space (to make a simplistic analogy) they'll continue to be "close" in a topological sense under any linear projection to three-dimensional space. Or for a different analogy, if objects group together under a filtration, they'll continue to group together under a coarsening of that filtration.
"Go well together" is different than "close together" if we are talking about matching clothes. Color matching effects is based on distances in the color wheel. Closest together is boring, largest distance is jarring. If you imaging a new axis only visible to tetrachomats, the color matching effects appreciated to a tetrachomat will most likely not have the same effect or even be visible to regulars.
Are Antico's colourful paintings really a result of her tetrachromacy, rather than artistic flair? If she's painting such that the colours of the paint match what she sees, then trichromats should also think the paints match what they see, since they're less discriminating than she is.
Distorting colour is a standard post-Impressionist painterly technique.
But the moonlight painting gives it away. Most people don't see any colours under low light, and being able to see and paint a colourful scene under those conditions is a unique ability.
Of course it could be imagination, but it doesn't look like it. The tree and the moonlight paintings have similar colours to the ones you'd see if you took a photo of a scene and turned up the saturation in Photoshop, with a few extra shades. It's a surprisingly literal and unimaginative form of exaggeration, and it's not how most painters distort colour for effect. So I'm more inclined to think it's a perceptual feature, not a creative choice.
Agreed, if the artist saw more range of colors than a normal person, I would think that they would paint using a smaller range of colors because they would find it sufficiently stimulating.
- It should be easier for them to paint highly photo-realistic scenes.
- They should struggle to find the right colors to buy in the shop.
- They should be frustrated with mixing colors because they could never get the color right as they see it.
Disagree -- paints are made from pigments that are real-world things, that show many colors. Why would it be hard to get the color right from paints if you can see more colors? Probably tetrachromats are overrepresented in the paint-color-creating world!
In addition, painting photo-realistically is more about edges and angles than colors.
Pigments are chemically designed to reflect particular wavelengths and combinations of wavelengths. But they are designed for the color gamut visible by trichromats. You can misx colors, but you cannot create primary colors by mixing other colors. Presumably tetrachromats would need a fourth primary color which might not be available.
Just imagine if the pigment selection were designed by a color-blind person.
I imagine paint mixing would be harder for a tetrachromat because they're trying to hit a target in a four dimensional space rather than just a three dimensional one.
It sounds like she doesn’t necessarily see new colors, she just can distinguish far more colors in things that look monochromatic to the rest of us. It’s not that the rest of us can’t see lime green, but we don’t see it in a pebble or tree bark.
I'm pretty sceptical, personally. I'm male, therefore not tetrachromatic, and long ago I had this idea of representing high contrasts as pure rgb values.
For example, if you hold up your hand to shield your eyes from the sun, that's a pretty challenging situation to paint. But the way the after images of the sunlight interact with the silhouette of the hand suggested to me that the idea could be conveyed by painting a shimmering primary colour halo around the hand. And sure enough, Antico's paintings look much like what I had in mind.
I find tetrachromaticity fascinating -- particularly, I wish there were a way to scientifically prove whether tetrachromatics actually perceive colors as qualia that the rest of us don't, because that is absolutely not clear.
Let me explain: our eyes perceive RGB, but we don't in consciousness -- the RGB is mapped somewhere, long before consciousness, further in the brain to more of a perceptual RYGB -- a two-dimensional space of warm/cold (RY/GB) against "lighter/darker" for lack of a better term (YG/RB). See [1] for more info. Psychologically yellow functions as a primary color even though we don't have a rod for it. (In reality it's much more complicated than this, since we perceive saturation, brightness, etc. but this is a valid simplification for current purposes.)
So it's entirely possible that tetrachromats map their four rods to the same RYGB box the rest of us perceive as qualia, only with a different mapping. Then, they can still distinguish between colors everyone else sees as the same (because different spectra), but they'll still perceive them as the same color qualia the rest of us perceive -- colors in the world will just be mapped slightly differently. The closest (but imperfect) analogy I can think of is wearing polarized glasses -- same color gamut, but certain things "compare" differently now.
Or, does tetrachromacy somehow also change the perceived-qualia RYGB model itself? So there's, say, a 3rd axis beyond warm/cold and "lighter/darker"? Or the span of the two axes somehow becomes wider to accomodate more information? Or something else?
Hope this is clear. Perhaps it could be tested psychologically, though -- simply by asking participants to describe the colors they see qualitatively, to see if the words they use in color comparisons (e.g. warmer/colder) are the same as those used by the rest of us... or if there's any new "feeling" component involved.
[1] https://en.wikipedia.org/wiki/Opponent_process - "...the cells were widely called opponent colour cells, Red-Green and Yellow-Blue. Over the next three decades, spectrally opposed cells continued to be reported in primate retina and LGN."
Not sure what the justification is for saying Y functions 'psychologically' as a primary color. It would be a secondary color (R + G) in terms of the light spectrum, and (as you noted) our cones are directly most sensitive to RGB.
To answer the question, as qualia cannot be compared from person to person, there is in principle no way to show that they differ (or are the same) objectively. A sort of relative comparison of qualia within an individual (as you propose) will also not get you there, as it may be that the individual is simply more sensitive to changes along the gradient, not that they are experiencing a new color, and that's assuming we are able to use an objective comparison scale which we aren't.
See the link I included on the opponent process. It explains how we have neurons that respond specifically to red/green and yellow/blue. That's why Y is psychologically as primary as the other 3.
Here's another way of looking at it: psychologically, we don't perceive yellow as a mixture of red and green, the way we perceive purple as a mixture of red and blue. Yellow isn't "perceived" as a mixture of anything in our minds -- it's perceived as primary. If you say "it's kind of a reddish-green", nobody is going to think, "oh you mean yellow!" While orange is perceived as a mixture of red and yellow, for example.
Remember, I'm not talking about what's happening physically with wavelengths -- I'm talking about psychological perception of colors.
>I find tetrachromaticity fascinating -- particularly, I wish there were a way to scientifically prove whether tetrachromatics actually perceive colors as qualia that the rest of us don't, because that is absolutely not clear.
There is an African tribe that can see more greens and browns, due to their genetics and it has been proven for them.
Don't quote me on this, but I believe as a whole qualia has been proven. That is, we all do experience the world differently, but we can both point at the same thing and give it a same name. Words like 'red' are just pointers to the colors we see, and everyone sees it differently. This, ofc, doesn't guarentee we can see more or less levels of detail, just that we what we do see can be different.
I won't quote you... because qualia is not "proven". :) I mean, qualia exist obviously, but there is absolutely zero evidence one way or the other whether we perceive the same qualia or not. It's a completely open question in philosophy, because until we discover a way of analyzing conscious qualia using scientific instruments, there are no experiments we can imagine that would reveal a meaningful result.
> So it's entirely possible that tetrachromats map their four rods to the same RYGB box the rest of us perceive as qualia, only with a different mapping.
If they did this then wouldn't they necessarily also confuse some colours that trichromats can distinguish?
I think certainly, yes. I wonder if that's been researched?
That wouldn't prove, but it would strongly suggest, that they're seeing the same qualia as the rest of us in the end, just mapped differently. Particularly if we could find "symmetries" -- i.e. for each area of new distinction they see, there's a corresponding area of distinction that collapses.
I don't see where there's much question about them perceiving differently. The ability of people to distinguish different colors is limited by the peaks of sensitivity of the rods in our eyes. By adding a fourth it's a new where they can distinguish better between colors that fall in the valley between the red and green cones.
I saw a six color channel video system at SIGGRAPH some years ago in their emerging technology exhibition. I believe the developer may have been Sony, but could not find an online reference. The additional colors were approximately midway the R-B-G colors conventional used. They claim they could display more of the color that people normally are sensitive to. And they had a 6-color monitor side-by-side with conventional showing how nature scenes were more vivid in their system. Of course every part of the system had to double up: video camera, transmission, storage, display.
I do not know if subsequent technologies like OLED, Quantum dots, HDF capture much of the color increase of the six channel system.
I do not know if the six color system could be used to quantify tetrachromacy.
Quattron TVs tried this with a dedicated yellow pixel and weren't that good... I highly doubt we'll see something beyond RGB (unless it's a first class citizen from camera to TV)
Sharp had a four primary display on the market (added yellow), not sure if it's still around. They hired George Takei to do some of the marketing at the time.
I wonder how such people experience pictures, movies etc.? All color reproducing technology is based on the the three-color system.
I'm skeptical of the articles claim that the painting gives us any insight in how a tetrachromat perceive the world. This is just like claiming a color blind person would be able to perceive full-color vision by looking at a painting. Never mind that tetrachromat painters would have real difficulty finding the necessary color pigments to reproduce what they see.
The title is misleading. The extra cone allows tetrachromats to appreciate individual colors that the normal optic system would “average” into a single hue. The visible spectrum is the same for tetrachromats: they cannot see infrared or ultraviolet wavelengths. These individuals see more color detail, not more colors.
> These individuals see more color detail, not more colors.
If you're not able to differentiate between colors you're not able to see those colors.
Hell, your argument can be stretched to stating that there's no difference between monochromatic and trichromatic vision as long as the covered light spectrum is the same.
You misunderstand. Any trichromat could see those colors as well, they would just need to be much closer to the object in order to distinguish them. You are still thinking about them seeing more colors. They see more detail in color. Detail is not a matter of visibility but one of perspective. With a closer perspective you could see those colors as well.
Dichromatism is a disorder. Our brains expect a trichromatic signal and when it only receives dichromatic information the hues are “repeated” because a cone (usually the one responsible for green) is not available. In people with green-weak color blindness this makes green look like a “weak” reddish hue. Tetrachromats’ brains are still expecting a trichromatic signal but they get more information than is expected. That means that the image contains more information or detail but the colors are not nee colors.
That’s not how brains or vision work. The brain is not “hard-coded” for trichromatism. Were that the case we would not be trichromats in the first place.
Disagree. They are not be able to perceive a larger spectrum of wavelengths but they may perceive more colors. Just like a person without green cones would be able to perceive fewer colors.
Would you also say that normal-sighted people "see more color detail" than those with deuteranopia? Sure, there's an experience of perceiving color when deuteranopes look at something green, but they still don't know what green is.
Depends on what you mean by more "color detail". Assuming that the activation curve of the 4th cone is sufficiently different, it's definitely possible to create two different spectra that a trichromat would be unable to distinguish between (regardless of how close they were or how long they stared at it) that a tetrachromat could easily distinguish between.
Both. They can't differentiate between red/orange/yellow, can't differentiate greens from grays, but can see further into UV at the cost of not being able to see as deeply into red as you can.
I'd love to see a tetrachromat who also knows about scientific color theory (tristimulus curves, CIE XYZ color, chromaticity and whitepoints, ...) explain how the color science would looks for them (do they have 2-dimensional hue, and 3-dimensional chromaticity diagram?)
I wonder if commonly available color changing smart bulbs, such as Philips Hue bulbs, have fine enough color control to be able to produce color changes that only a tetrachromat can see?
If so, that would be an interesting way for a tetrachomatic magician with a mentalism act to have their assistant pass them information. In particular, it would almost certainly work to fool Penn & Teller on their show "Fool Us" [1], where it often comes down to whether or not the mentalist can find a way to pass information that Penn & Teller can't spot.
I'd be really surprised if the Hue internally doesn't just have three lights (R, G & B) that combines to produce all colors a human "trichromat" can distinguish.
To my mild surprise, 10 minutes googling did not find any description of how it works.
Adding genes for more opsins is interesting. However, the regulatory mechanisms for developing the retina and differentiating cone types appear to be quite complex.
Most of that 6% don't have the useful form of tetrachromacy. Their response curve of their extra cone is almost identical to one of their existing ones. This is like deuteranomaly (the most common form of colourblindness), in which people can't distinguish red and green because their L and M cones are too similar.
12% of women are tetrachromats in the sense that they have 4 pigments, but only a small minority of those are functional tetrachromat, where the 4th pigment is sufficiently shifted from L or M that it can actually pick up relevant information.
As the article notes, Jordan & al spent 20 years researching tetrachromacy before they found a functionally tetrachromat individual.
May have this. Odds don't necessarily imply even distribution amongst a given sub-population. A person could know 1,000 people and still not know a single tetrachromat, and another person could know 10 people and know multiple tetrachromats.
Is it possible that tetrachromat people may have a lot of trouble shopping for painting supplies? Since the dye or pigment used on the packaging may not be the same as the dye or pigment in the actual pastel/watercolour/whatever.
Wouldn't it be really confusing?
Are there lines of painting and art supplies specifically for tetrachromats?
Super interesting. My notes as a colorblind man (might be misunderstanding some stuff though):
(Being a little sloppy with sex stuff here. Not all women have two x’s, women can be colorblind too, etc.)
• Two of our usually-three cones are specified on the X chromosome
• When one of a woman’s X’s specifies an anomalous cone she ends up with a 4th, anomalous type of cone.
• This happens ~14% of the time for women.
• That’s about the same percent as color blindness in men.
• That’s not a coincidence. Because color blindness comes from one of these women’s sons getting that anomalous 4th come instead of a typical 3rd cone. This anomalous cone tends to overlap more with one of the other cones in its range of perceived frequencies, which is what causes color blindness.
• But only a small percentage (not sure what percent yet?) of these women with 4 different cones actually seem to be able to perceive more colors
• that’s because the 4th, anomalous cone might basically fully overlap with one of the typical ones in its perceived frequency range, so it doesn’t really give the brain any additional info
• one question I have: so it seems like not all these anomalous cones are the same. Is there a fixed number of types? Or is it more of a spectrum? Further, are /all/ cones on a variable spectrum? Or is almost everyone’s blue cone exactly the same?
• this was interesting: colorblind men actually have a set of colors they can distinguish that people with normal color vision can’t (the article explains why)
• in this study they found colorblind men (but by looking at unusual things they /could/ see, not things they couldn’t? Not sure) and then tested their mothers to see if they could see extra colors.
• Most of them couldn’t. One of them could. The study was only like 9 people? Safe to say /all/ of these women had 4 types of cones, even though only one of them had a sufficiently non-overlapping fourth one to get some benefit?
• As a colorblind man, I’ve never noticed an ability to distinguish colors others can’t. Only the opposite.
• it’s intellectually neat to know that’s possible, even if it doesn’t tend to “come up” in everyday life.
• It souuuunnndssss like the amount of extra color vision that these tetrachromats get is only the same as the extra color vision /I/ get—that same “theoretically there, but doesn’t seem to come up in everyday life” thing. That’s a little disappointing—I though tetrachromacy was more kooky.
> Or is almost everyone’s blue cone exactly the same?
I get a stronger blue channel from one eye than the other. So I'm quite sure that there is variability, it's a matter of degree. Also, research into language and culture shows that the brain is heavily influenced by colour as well. Some cultures have difficulty seeing differing shades of blue or green that westerners think are trivial.
My favorite sex-affecting genetic incident is Androgen insensitivity syndrome [1]. People with Y chromosome who have complete androgen insensitivity syndrome [2] have fully female external bodily features; their reproductive systems are ill-developed, and they are infertile.
> Most individuals with CAIS are raised as females. They are born phenotypically female and usually have a heterosexual female gender identity; However, at least two case studies have reported male gender identity in individuals with CAIS. [2]
Alternatively take photos with a normal camera and then with the same camera with a coloured filter. Choose the filter so that it only partially interferes with each colour of sensor (magenta should work well). Then the two images have six independent colour channels between them.
When they're well into the double-digit percentage of the population, I guess. (Not just technically tetrachromats but actually able to discern a 4-dimensional color space).
Since they can perceive more colors, it's never an accessibility issue, so it's far more important to accommodate dichromats, and that's already very hard because we can't tell how a person with a different set of cones would perceive a particular color just by looking at it.
Also, we already have a color model that can't reproduce true cyan as perceived by "regular" trichromats, and so far that hasn't been a real issue.
What is the problem with cyan? That there is no adequate color space that can create more or less cyan? I would think it is just a mix of green and blue, no?
Is the same true for magenta as well? Is it a problem to convert between RGB and CMYK?
For anyone puzzled by the graphic's D50 whitepoint marker being in yellow, offset from the color background's whitepoint (the white intersection of the 3 "arms"), yeah, that's wrong. There's historically been a lot of broken chromaticity code out there, and associated flawed diagrams.
I see, thank you. I took a long look at the diagram and could not discern a difference between colors within and outside the triangle until it alarmingly slowly dawned on me.
Would really like to have a comparison between a monitor that can display those colors now. Apparently there are some more expensive monitors that can display an extended palette.
Some screens have a yellow colour in addition to the usual RGB. For trichromats this just lets us see more intense yellows, but for tetrachromats it would let the screen display every hue they can see, rather than just a subset.
Yes, but the software to drive those (4 color SPR) subpixel rendered screens is limited to an RGB color gamut at the compression and transport levels (DSC / DisplayPort, HDMI). Actually, I wouldn't be surprised if their weren't optimizations most of us can't see that could be jarring for a tetrachromat.
Hm...with a single screen, probably not. With two screens with different output curves for each of R, G, and B; it may be possible to display a color that looks the same across the screens trichromats, but different to tetrachromats.
Probably not: colors are pretty much always expressed in terms of RGB (at the "standard" trichromatic peaks"), and displays work in those terms. So you couldn't express the colors in questions, nor could you have the display show them.
Outside the on-line/web sphere, there are quite a few other ways to express (or specify) colours, but alas, they all seem to have been made by and for trichromats ;-}
The display monitor would make a considerable difference in the reliability of the test.
As the article and the name of the condition state, there is a physical difference in the optic system that causes this condition. No subjective analysis is needed.
I have always found describing color shades interesting/mind-fuck. Does the "red" that you see "red" to me? I am red-green color blind and a lot of "red" looks "brown" to me.
Color doesn’t actually exist. We don’t see actual objects as they are, we see the light that bounces off of them. Brains will create their own way of mapping wavelengths to colors, so therefore we do not see the same thing, but we perceive it as the same.
If I opened your brain and swapped your red with blue, you would not notice.
Yes, it's kind of like wondering "Does my computer store [R,G,B]? Or is it actually stored as [B,G,R] in memory? Are they represented in 2's complement form?", etc. Functionally our perception of colour is just how we mentally represent and compare vectors with 3 (or in this case 4!) components.
That said, our shared physiology and biology as humans makes my default assumption that red looks about the same to me as to anyone else. Unless they're colourblind or tetrachromats, of course.
Summary: About 12% women have a mutation due to which they have 4 cones instead of 3 in their pupils. Most of the time the extra cone has an activation curve so close to another existing cone that it makes no practical difference.
But in rare cases extra cone has a quite unique activation curve and allows to differentiate mixes of wavelengths that are perceived as the same color by most people.
Further, I'd think the brain must value that extra information, lest it'll just ignore it. If a kid is told that oranges are orange and bananas are yellow, will it actually develop a sense that there are different shades? Otoh, the ability to pick the bananas which are just perfectly ripe or the sweetest strawberries might come in handy. Oranges, bananas and strawberries might be bad examples as to some degree trichromats can perform such feats, but there might be other fruits and vegetables for which this would be more difficult.
In curious, would you say she has a particularly unique clothing style? And would you say she has a better than average ability to match? Also curious if she has a profession or hobby that utilizes her extra abilities. Does anybody else in her family also have this condition?
He's taking it too far but yes, in this sense there is "oddly" no sex egalitarianist asking for a way to compensate men for a so-called women privilege or to level everyone down.
Generally all common kinds of colorblindness are considered in accessibility. We are expected to accommodate to this mostly male problem. Using primary colors and strong color contrasts is the normal way of doing things, using subtle shades that color blind men dont see is considered bad thing.
With exception of electrotechnic which is historically male dominated and uses ridiculous color system that ignores the issue entirely. Dunno why. I am all for changing that.
Color codes on resistors. The worst part is brown, red and orange. I am good at distinguishing colors (was tested no issue) and sometimes it was quite difficult.
I am not, that's just how things are these days. And if you're talking in a condescending way to me as if I am the angry white male, I assure you I am not white and not even a Western man and never been to the west.
If men were the ones who had this the tenor of dismissiveness sprinkled across our comments would be transformed into the desperate attempt to convince that we all had this
100x or "resolution" doesn't convey it correctly in my opinion. It makes you think they can distinguish more shades of the colors we all know. As if it was a quantitative difference. But the difference is qualitative, they see colors we don't see. We are color blind to them.
I don't know where they get the bit count from, it seems to be based upon an understanding of the cone's operation that I've never seen justified in any of these articles.
Assuming that the cones of different frequency range have approximately the same degree of sensitivity, I'd be thinking that the number is about n^(4/3) where n is the number of colours perceivable by trichromats.
But even if that's true - which I doubt - the additional colours are in unlikely to have a useful distribution, and will be centered around the frequency response curve of the fourth cone (I believe it's generally in the yellow spectrum; somewhere between red and green).
100x more colours is just nonsense. Trichromacy is already sufficient to see all the colours. The only difference is that some things may look like they are a different colour (which means they might be able to distinguish two objects where tetrachromats can't).
By that logic, white, black, grey or brown or pink does not exist either. The article confuses human color perception with wavelengths. It is not that purple doesn't exist, it is just that a rainbow does not contain all perceptible colors because it only contains colors represented by a single wavelength. Just like our ears can perceive chords as different from a single "average" note, our eyes can perceive combination of multiple wavelengths.
It doesn't require any pop-psychological explanation - you can easily make an electronic device which detect the color purple. It just needs to be sensitive to more than a single wavelength.
> Whilst we can see violet and blue next to each other, there's no purple. Because purple doesn't exist.
Back in reality, "purple" and "violet" are synonymous.
The article also makes the completely unsupported assumption that the color you "should" be seeing when you look at a mixture of wavelengths is the color of the average wavelength of that mixture. That's how it decides that purple "should be" green. But that's nonsense.
> When you see red and green for example, the L and M cones both fire, and your brain interprets the result as something near both. And what's near both is yellow. So even though there's no yellow light entering your eye, your brain imagines the result as yellow, because both cones are being stimulated in similar amounts.
This gets the causality backwards. When you see red and green, your L and M cones both fire. And you interpret that as yellow, because yellow is what you perceive for that pattern of cone activation. To the brain, cone activation patterns are all there is. The question "what single wavelength would best approximate this activation pattern" is not even part of the model the brain is working with. But, obviously, if there is a single wavelength that approximates the activation pattern of a mixture, you'll perceive those two things as being similarly colored. Is it necessary for the single wavelength to be the arithmetic average of the wavelengths in the mixture? No.
Except when they’re not. People who have to think and talk about color on a regular basis, such as artists, sort colors into much more detail than people who don’t.
Have a look at the Wikipedia pages for purple (https://en.wikipedia.org/wiki/Purple) and violet (https://en.wikipedia.org/wiki/Violet_(color)). The image examples given for purple range widely, from a photo of some grapes I would call more blue than purple, to a dress that I would call magenta at best. And a color swatch that is somewhere in the middle of that range.
Meanwhile the page for violet leads with a specific wavelength, and a set of photos that are all very close to the swatch above them. This particular color could fit into the range of colors given as examples of “purple”, towards the bluish end of the range.
"Purple" is perhaps ambiguous, but it is true that magenta (a reddish purple) does not exist in the rainbow. But you are correct about the rest; the article is bs.
No, when you see purple you are not seeing something your brain "thinks should be green".
It's true that purple is a non-spectral colour. The rest of what that article says about purple is nonsense. (Perhaps motivated by the analogy they want to make with what they say about "customer experiences"?)
She also sometimes see colors in her dreams that are outside of a pallet humans see in real life, but after she wakes up she can't describe them. It's not one color or one hue, there are several colors that she can only experience in her dreams.