Are You a Tetrachromat?

June 8th, 2008 by timbotron

If all you see are three circles filled with dots of the same color, you are normal. If you see something different (such as different colored letters inside each circle) – immediately contact me in the comment section below.

You may be a tetrachromat: very rare and super human.

A tetrachromat is sort of like being a super taster of color vision. To date, only two or three people have been identified as potential tetrachromats.

You might be one.

In simple terms, here’s how normal color vision works:
We all have three types of color photoreceptive cells in the back of our eyes (the retina) – which are often called the red, green, and blue “cones.” We are trichromats. Each of these ‘flavors’ of cone is sensitive to a particular range of colors of the spectrum. And usually when we perceive a color, it is the result of a combination of signals from more than one flavor of cone. For example, seeing “orange” is the result of a moderate signal from a green cone and a stronger signal from a red cone. And we are able to distinguish the range of orange hues from each other by the different strengths of green and red cone signals that each orange hue generates (darker orange would have a stronger red signal, etc).

What would happen if you had a fourth cone, an extra color photoreceptor?
If you are a tetrachromat, the most likely scenario is that you have a mutant form of the red cone while also having normal form of the red cone – two types of red cones that are sensitive to slightly different ranges of the red end of the color spectrum. You would not be able to see extra colors the rest of us can’t (sadly, no ultraviolet vision, etc.), but you would be able to make distinctions between very similar colors that the rest of us cannot. Two samples that would look like the same color of red to me would look like dramatically different reds to a tetrachromat.

The most likely candidate for being a tetrachromat:
• You are a woman
• You have men with red/green colorblindness in your family.
• In particular, you have a son or father with red/green colorblindness.

If you can see more than colored circles in the three tests above, drop me a line in the comment section below.

Your Ad Here

218 Responses to “Are You a Tetrachromat?”

  1. Elina Says:

    there must be some other way too for me to proof the rest of world about my rarity and superioty among humans.

  2. Jerry Says:

    Huh. Does this tetrachromacy test work on an RGB monitor? Also, I’d think that all bets are off after the test has been compressed to a jpeg. I think one of the jpeg compression algorithm’s features is to simplify photos by removing colors we can’t differentiate. Interesting info though.

  3. Timbotron Says:

    Good point.
    I accounted for the jpeg compression. The color microdifferences still exist after jpeg compression, I checked.
    However, I don’t know if certain older monitors or ones with significant color limitations will allow these graphics to work properly – they may not properly portray the minute color differences.

  4. Robyn Says:

    It could be my imagination but after looking at it closely my brain (or eyes?) picked out a letter in each one, together spelling a word. I don’t know if I should say it….then everyone might see it! If there really are letters in there, maybe you could let me know.

  5. Joey Says:

    2 or 3, 3, 8

  6. Pam Says:

    I see characters in the red and orange circles but not in the green.

  7. kim Says:

    The three circles all have the same dual shades per color

    i think i am a tetrachromat: can see different shades of red, green & orange per circle

    mmmz wonder what to do with my super-vision :P

  8. Neha Says:

    It seems like I see and E in the green O in the second and a D in the third..

    I wonder…It took me a while to figure out the one in the yellow though.

  9. Karasu Says:

    I seem to see a few things…..I’m not going to say anything, because it may inspire frauds to say they saw what I might say….Then again, I may not truly be one….With everyone here doing so, it’s unlikely…..Either way, you said to post if we saw anything, and so it shall be.

  10. Monica Says:

    Yes, I believe I am slightly a tetrachromat. I can see the letters inside the circles, they’re all a shade lighter than the the circles.

  11. Batman Says:

    The only thing i can see is what looks like the letter “T” in the orange circle.

  12. Frans Says:

    My first thought was the same as Jerry’s. In RGB a color is represented by thee values, each representing the intensity of one of the primary colors corresponding to our eyes’ receptors. A fourth primary color would completely disappear in this algorithm. What might happen, is that for some people the ratio in sensitivity for the three colors is a bit different, and two certain colors represented by different RGB values may look the same to one person, but different to the other. Interesting subject, but I don’t think t you can spot tetrachromats this way. Just my opinion, might be wrong.

  13. Helen Says:

    Is there a B or an 8 in the red field?

  14. Annette Says:

    My son and my brother are both red/green colorblind. I do see numbers in all the circles but not in a bang, of course, sort of way. It took a few seconds. Maybe I’m just matrixing, but I don’t think so.

  15. Mea Says:

    I’m currently being tested for tetrachromacy through a color lab outside of Flint Michigan. They showed me things in print that were similar to this in which I saw differenceds they didn’t, but I’m not noticing any differences here. From what I understand this has to do with the dway in which most monitors display color. My only point is that this is slightly misleading, and you should note that this is not definitive proof against tetrachromacy.

    Especially since registering of color from light is not the same as reflective color which is color percieved from objects. The computer will display light wavelengths where as printed objects will display reflected colors. I suggest that you reanalyze your test and to fine tune it and do some more research on the subject. It really IS fascinating, and while my results have not been determined yet, you could be discouraging some women who do have tetrachromacy and are exploring their acuity for color of their own accord.

  16. timbotron Says:

    You’re being tested for tetrachromacy?!?
    Anyway . . . you have a good point about monitor color issues (though reflected vs. transmitted light should not make any difference regarding detection); the concern would be older/cheaper monitors that have a smaller color range, they could generate a false negative because you aren’t seeing the color microvariations in the test clearly. However, more up-to-date monitors offer a range of color differences at the level I hope to be testing for.

    TO ANYONE TAKING THIS TEST: If your monitor is a cheap piece of sh!t, this test may not be effective.

  17. cory blankers Says:

    Yeah i see different shapes/shades, but also a computor screen cannot project tetrachromacy, at least not to an extent where a test would be accurate. I do have synaesthsia however, i don’t know if this is connected in any way (?), and i am a female painter. Could tetrachromacy affect our way of processing our environment visually, or what is, the general hypothesis, if there is one?

  18. Zoe Says:

    I was waiting for the punchline here, a “stop believing you special, your just an individual like everyone else” type of thing… guess not.
    Interesting concept though.

  19. Who can know Says:

    I’m a super taster already so I think it’s very unlikely I have this Tetrachromacy as well. Also yeah computer monitors can’t show such a small difference in colors I checked the color span on my Mac 2008 series and from what I can tell everyone who left a comment on seeing letters is just seeing things the colors are exactly the same. The way a computer would do this is combine two colors to get the nearest possible hue of color. This combining thing would screw up the entire system also it has not actually been proven that this actually exists among humans.

  20. Who can know Says:

    Oh yeah and also I’m a dude and no one in my family is color blind in anyway. More proof I don’t have this and in terms of anyone actually having this thing your chances are less than 1 in 3 billion.

  21. Who can know Says:

    Even thought I’m almost 100% sure I don’t have this I do have increased ability in night-vision.

  22. Patricia Says:

    Hello, if you are researching tetrachromacy and whatnot, i was very itnrigued with this all when i was looking at colorblindness tests and i could see both what the color-blind should be able to see but not the regular people alongside what regular people could see but colorblind not. It got me really interested in the fact that my mother, grandmother, uncle, one more aunt and a good number of male cousins are color-blind whilst others in the family have gone on to study art and design and are really keen on colors. I have found very little in regards to having color blind females in a family as well in relation to this. Any information on females being color-blind and it’s relation to tetrachromacy?

  23. Sarah Says:

    I definitely see a few shades of orange in the orange one, and a couple shades in the green. The red I’m not sure if I’m actually seeing another color or just the pixelated edges of the letters, but it seems there’s couple shades of red in there too.

  24. bluu Says:

    WOW! i can see it! i see three circles: a red one, an orange one, and a green one

  25. MiraMira Says:

    I’m curious if you have anyone yet positively identify the figures that you have displayed?

    I have no idea if I’m a tetrachromat, but I would lean toward it being a strong possibility. My grandfather was color-blind. My son is color-blind (deutero-…I discovered this when he was ten, and we were playing “I Spy”, and he spied a red Exit sign that was actually green). I’m in a design profession, and I’ve always been fascinated by color — fun to play with, fun to look at, just awed by the interplay of different hues and saturations, etc., etc.

    I’m also intrigued that Mea has been tested by a color lab.

    Strange for me — I love blues and greens, but for me, when I look at most spectrums as displayed on a computer screen, it’s actually the red end that looks like it isn’t as complex as the green/blue end.

    Curious if there will ever be an easily-administered test for tetrchromacy…

  26. Tree Says:

    A lot of people are staying they see a little bit of something.

    ~ If your seeing shades, it could be due to the size and density of dots in a part of the circle- look at pen and ink pointillism..

    ~ Also the human mind locks onto patterns; if your seeing a letter make sure its not merely that your seeing a pattern of large or small dots in the circle.

    ~ Really, you cant be “sort of tetrachromatic” or see a little bit of the 4th color. You either have a forth cone or you don’t. If you’re sort of seeing something its either pattern, or shade do to dot size, or will power to believe you see something.

    Source: Visual Artist for many years, well studied in color theory.

  27. Guy Says:

    Yes I can see different shades of all of the colours, except for both red and orange, only about 2 different shades while green I can see about 4. I’m just guessing but maybe I have a higher green “sensory” than that of red. Nobody in my family is colour blind (that I know of). BTW, I’m a guy too, so if i was to be a tetrachromat, that means not all tetrachromats are female.

  28. stu Says:

    Are there little bluish stars? Particularly in the red.

  29. sciteach Says:

    I’m a science teacher and used your page for class. One girl saw 2, 29, 15 at once. Another 2, 6, 8. Third 3, 32, 4; finally none, 35, 32. Are they just messing with me because I’m a guy?

  30. James Says:

    Ok so I read that its physically impossible for guys to be tetrachromats, due to only having X&Y instead of X&X chromosomes.
    But when I look at the red circle sideways I can make out a distinct shape, and same for the green. This maybe because I want to see something, or because the human brain latches onto patterns (as was mention by Tree) but I could swear I can see a number, tilted slightly, and a shape in the green one.\
    Anyway just the imput of boy with a family full of eyesight issues….

  31. Diego Says:

    You can’t do this test on a computer!!! You would need a monitor able to generate 4 independent frequencies of lights. The way to test a tetrachromat is to challenge her to tell a pure orange from green and red overlapped. Your monitor should be RGBO (O for orange)!!

  32. Joshua Says:

    I saw nothing. My brain made patterns out of the dots, but that was about it. No different shades. I even tried cheating, such as by enlarging the pictures, turning my monitor up to full brightness, but still, nothing. Were there really different shades in there?

  33. Joshua Says:

    I didn’t notice any letters in the circles, but perhaps if I stare at them long enough, maybe I’ll see Jesus in there.

  34. EvanB Says:

    Is it M,K,E?

  35. Julie Cooper Says:

    I used to be able to see these numbers but after cataract surgery with lens replacement I can’t. Have you heard of this before. Of course my vision is worse than in my misspent youth when I last took the test. Now 20/80 and 20/60. Maybe I just can’t distinguish the letters.

  36. Ken Says:

    I see 9 – 4 – 3. Not in numbers but in dots. Like dices’ pips.

  37. Will Says:

    I also am curious whether anyone has had this test work for them. Has anyone seen something and had it confirmed by the author that they were correct? That would be interesting to know.

  38. Silvia Says:

    My friend got this for me to look at it after I told him that people tend to make fun on me for the way that I see colors. After I looked at the circles I can tell that they are several letters and numbers in them and they also seem to move and interrelated one with the other. I don’t believed that I can see more than other people but now I’m curious. It seems that I can view them more easly with my left eye. If there are some indeed, thank you. Now I know that I’m not color blind as I been called and maybe I can see different hues on colors.

  39. Dan Says:

    I don’t think this test is valid, at least as it appears in 32-bit color under jpeg compression. After downloading the enlarged .jpg and using a series of software hue and luminiscity thresholds I was unable to discern any letter formations.

  40. Ryan Says:

    The JPEG compression certainly hurts things (mostly noticeable as the ringing around the edges of each dot). Also, most LCD monitors only operate at 6-bits per color component, meaning only 64 different levels of gradiation can be displayed for each of red, green, and blue. However, many monitors use various methods to fake more levels of color.

    All that aside, playing around in photoshop I was able to find a letter in the orange dot (threshold the colors around 140-145 out of 255). I gave up on the others. But at least one dot maintains the information. Even after thresholding it’s still rather hazy and ill-defined. I do think a 6-bit monitor would be good enough to show it though.

    A true tetrachromat could say for sure how easily visible any of the letters might be.

  41. Mark Says:

    There is a character in each one, it’s not a mind game. If you are staring too long you will never see it. You have to look at the complimentary color (opposite color on the color wheel) for each one for about 15 seconds, then quickly look back at the screen. They are not simple “Ariel” type fonts. Photoshop tweaking is cheating! I’m a male artist at 37 years of age. I can see the yellow-orange one fairly easy, the red a bit more difficult, and the green I can see but my eyes and brain fight over interpreting the green.

  42. Caram Says:

    Love the test… I’m currently researching into how to interpret colour-blindness in type and was, of course, fascinated to find that there is superhuman vision… I’m thinking that it would like something like an HDR picture with a fuller colour spectrum… did anything come out of this?

  43. Miah Says:

    I see D or B in the first, S in the second, and I can’t yet distinguish the third.

  44. Elexis Says:

    I see 2 on the first very clear and bright. Nothing else on the orange and green.

  45. Snowball Says:

    I’m not sure about the first circle, I think there’s “P” or “R” in the center. In orange i see “T” (the lower right corner) and “G” on the green (upper left).
    Sorrry for my bad english.

  46. Isabelle Says:

    I don’t think this test works in any regular personal computer at present.

    Check this Guardian news link:

    “An enhanced sense of colour is of limited use in the modern world because all colour reproduction is based on a three-colour system. To a tetrachromat, television and photographs never quite reproduce colours accurately. They would need a special television or computer monitor with four colour guns or a special colour printer.”

  47. Jen Says:

    I see something and I can tell its the same shape in all the circles, but in the red its nearly impossible to see and in the orange and green I see the same shape but can’t tell what it is cuz its too slight. Maybe if this were a printed test I could tell for sure.

  48. Ann Says:

    How can you create a test for tetrachromacy using an RGB color palette?

  49. Gail Peterson Says:

    I see 5,6,3?

  50. lizzy Says:

    i see an eight in the red, a g in the yellow orange, and my eyes notice that the greens are different colors but don’t form a coherent picture- i’m going to check the picture in photoshop to see if i’m right

  51. Bill Says:

    As far as I know, all PC’s with ‘true’ color are 24-bit, with the other 8 bits being “alpha”, used as a transparency scheme. If “32-bit” color were 32 bits, we could add a 4th gun, the extra one being the rare color.

    Perhaps some MACs or lenix might have the 4th gun? I don’t really know.


  52. TrueBeliever Says:

    I see England, I see France…
    I see the face of Jesus, Mary, and Satan in the Green, Orange, and Red circles (respectively)
    For some reason, Jesus is laughing…and pointing at ME! Mary has the words “you’re wasting precious time” around her, and Satan is pointing to other links for tetrachromacy tests…
    Well, enough fun…for now…thanks for the entertainment. I really could only see the Red, Orange and Green circles, am not a female, and don’t know of anyone in my family that has R/G colorblindness. I wish I had X-Ray vision though…

  53. It's me Says:

    For me i can’t see and colour defined shapes or numbers.
    -and after looking at them for a while i seem to come up with random letters and numbers with the dots themselves.

    But in the red one the smaller dots are a different shade and maybe a little in the orange yellow but the green no change.

  54. Jessica Troisi Says:

    You are all idiotic. He’s playing you for fools. First off, only females can genetically be tetrachromats. Secondly, you CANNOT generate a test for tetrachromacy on an RGB computer moniter. Look at the studies done in university vision labs- it’s much more complex than “hey guys…look at these circles!” …bunch of morons. That’s the only amusing thing about the web- watching retards fool other retards. Look up that deadly chemical called Dihydrogen monoxide while you’re at it. Do some research before you fall for some computer geek’s “home genetics” test

  55. timbotron Says:

    1). In theory, tetrachromacy can come about in more than one way, not exclusively female heterozygosity. For example, a “mosaic/chimeric” male (though very rare) could also have the potential to be a tetrachromat.

    2). You can use an RGB monitor to detect tetrachromacy – it is simply the ability to detect color subtle differences that are not noticeable to the average trichromat (most of us).

    3). This isn’t a “home genetics test,” nor is this test designed to diagnose tetrachromacy. If an individual is able to identify the characters within one or more of the color samples above, they should contact a specialist to determine if they are indeed a tetrachromat. There may be other perceptual abnormalities that would allow someone to see these color differences (a number of retinal disorders, etc.)

    4). Yes, I am a retard. But not because of this.

    5). I recommend switching to decaf.

  56. Jessica Troisi Says:

    I didn’t mean to sound rude but I hate it when someone creates a webpage with info specifically designed to give people misinformation. Retinal disorders not genetically caused will NOT create a tetrachromat and yes- you DO need female HOMOZYGOSY (get your info right) to have the required genes.
    I’[ll say it again and I beg everyone else viewing this website to look into this- RGB monitors will not properly display color thresholds in a way that is conducive to testing for tetrachromacy. It’s a fact.
    You cannot show someone a red dot and ask if they can see a difference between that dot and the one next to it when it’s only a shade or hue different- that’s not what tetrachromacy is. It’s not how “red” (or green) something is when compared to a different hue of red. There is a fourth primary color involved. You just don’t get it.

  57. timbotron Says:

    Jessica . . .

    Tetrachromacy does not actually involve a fourth primary color. It involves having an “extra” cone (that is, a color photoreceptor that is shifted far enough away from the wavelength maxima of the other “normal” three cones to offer yet another POINT OF COMPARISON for color perception). This has been *predicted* to happen in women who are genetically HETEROZYGOUS (having two non-identical genes) for the “red/long” wavelength cone. That is, they have a “normal red” cone, and a “damaged red” cone that is far enough away from the “normal” to function like an entirely separate cone. Thus, offering a fourth reference point to perceive color differences. This would not allow the person to see other unseen colors, etc. but it would allow them to see a greater number of distinctions between colors which would look identical to the rest of us.

    You are right though: retinal disorders that are not genetically generated couldn’t make someone a tetrachromat. However, a HETEROZYGOUS female may not be the ONLY way someone could be a tetrachromat. There is the possibility (however remote) that a male “chimera/mosaic” can have two different (HETEROZYGOUS) sets of genes for the three color photoreceptors (”cones”) – a “chimera/mosaic” commonly happens in humans when fraternal twins do not separate into two individuals in the womb, but become a single individual with two distinct genomes. It’s rare.

    This article is not specifically designed to give people misinformation. The use of an RGB monitor should not have any effect on this test, however a monitor with limited color range may not be able to display sufficient differences in the color tests above. This test does not require a Herring color scheme nor some other four color scheme.

    And finally, I do get it. I am a college professor: I regularly teach human genetics and the physiology of color vision. I also have a journal article published on the subject of the history of color vision and perception.

  58. Lilac Says:

    Um, I’m a woman, and my father is colour blind, and I’m pretty damn sure I have some tetrachromacy based on numerous past experiences and I’m not seeing any colour differences here. I can make out some patterns, but not in levels of colour and I have a good monitor.

  59. ryan Says:

    hey i looked at the last one for a period of time and i kinda saw a “R” word slowly come to view; its like periipheral visio, sorta, cos i stared at the middle, and the dots around it formed the alphabet R… hmm.

  60. Ken Ballweg Says:

    While anecdotal evidence is not strictly scientific, it is common for people to use the scientific method to try to clarify anecdotal perceptions of difference.

    What is clear is that many women report being able to see a wider range of color differences than men. There may be some level of training to it, i.e. being a guy I’m content with a reporting the world in a very limited palate of primary and secondary colors, but know full good and well there is a wider range of hues out there.

    But when my wife tries her best to get me to see the subtle differences that cause her to say “those don’t go together” it’s not stubbornness (or, more accurately, indifference to color nuance) that causes me to argue with her.

    We’ve done the, non-scientific method, some experiments in a large group of men and women, and some women cannot see what approximately half the women in the group can see. And, here is where it gets wildly non-sci, those with the enhanced color perception do appear to have a shared experience which may seem a little fuzzy as a result of differences in color naming conventions.

    Again, not publishable evidence, but highly suggestive of a physical basis for the differences. I do think there is more pressure on women who are not able to see the distinct differences, since most women grow up in a sub-culture that includes a wide range of color names and peers who can get very judgmental about people who can’t “match” colors at their level.

    How much is learned in the sense of being a culturally driven ability to focus on differences (it’s a woman thing as my wife exasperatedly says) is debatable, but the anecdotal evidence, backed by clear scientific findings, support the existence a sub-set of women who have a physically richer spectrum of color differences.

    Given all the back and forth about whether computer monitors are able to produce an appropriate screen, I would be curious to know if there have been people who have accurately responded with the figures you imbedded. As someone commented, the will to impose pattern on noise will allow some people to “see” characters in your non-rigorous “test” but those aside, how does it seem to be working as a quick and dirty screening device for tetrachromats?

  61. Jules May Says:

    timbotron said “And finally, I do get it. I am a college professor ”

    In that case, would you mind explaining a bit of your theory? Because I, too, am pretty sceptical.

    The premise of tetrachromacy is that (however it comes about biologically) the individual has receptors for four different colours of light. Monitor screens have emitters for only three. AFAICS, In just the same way that no additive combination of red and blue light will ever create green, similarly, no combination of red and green will ever create the fourth colour.

    Now, I’m well aware that monitor colours are not precise, and in fact are pretty splurged out. So perhaps a combination of bluey-green and yellowish broad-spectrum light might make something vaguely green? (Though I think I’d need to be convinced of that!) But for this test to mean anything, you’d need to know exactly what the spectrum of the three monitor primaries are (and specifically, you’d need know the overlap of the emissivities of the red and green emitters) /and/ you’d need to understand the backlight spectrum (which, for most cold cathode and EL backlights would be very peaky indeed!). Given the variability between CRT phosphors and LCD filters, then surely the test can’t have any validity?

    BTW, I had a go at extracting the images from your circles. (Cheating, I know, but I’m pretty certain I’m not tetrachromat). Yes: I’ve found the hidden message, and no: I’m not going to post it publicly. But what I did notice is that at any level of downsample, the effect disappeared completely, and upsampling made it very much more difficult to see. I do believe that the effect you’re trying to show – even if I bought into the principle – is pretty much swampled by the JPEG fringe effects. (Out of interest, why did you opt for JPEG and not something more controllable?)

    Umm – care to comment?

  62. david Says:

    each of the circles have other colours inside them. especially the orange one, its got yellow variations in which are shared in the red circle!

  63. timbotron Says:

    Thanks for testing the color samples and bringing this to my attention. I’ll give it a try it myself. If you’re right, I’ll have to revise the color test a bit.

  64. timbotron Says:

    Also . . .
    1). this isn’t my theory. This is what is known about the potential for tetrachromacy. This is not my personal opinion or theory I’m testing out.

    2). Tetrachromacy is not exactly having receptors for four DIFFERENT COLORS of light. Nor does it have anything to do with the ability to see something like “four different primary colors.”
    A brief explanation:
    Each of the three color photoreceptors (”cones”) is sensitive to a range of the spectrum, though each is most sensitive/responsive to a particular wavelength of light (this is called their “maxima”). For example, the “red” (long wavelength) photoreceptor is triggered by light ranging from purple all the way up the spectrum to red, however it is triggered most intensely by light that is in the yellow range (though oddly, it is called the “red” cone). We perceive color differences not by the signaling of a single type of cone, but by combinations of signals. For example, our brains perceive the color “light blue” from a weak “blue” cone signal and a weak “green” cone signal. Or, we perceive/see the color green “green” from the combination of a strong “green” cone signal and a strong “red” cone signal.

    Tetrachromacy is simply having an extra cone that is shifted far enough away from the existing three cone types that is functions like a fourth point of reference for making color distinctions (this fourth cone could still have a maxima very close to that of another cone type). It would not open the door to seeing some new unseen color, and nor does it have anything to do with extra primary colors, etc. It simply would provide another source of signals to the brain, allowing the person to make better distinctions between colors that would appear the same to the rest of us.

    I may need to strengthen the color differences in each of the above three tests to compensate for the possibility that some types of computer monitors aren’t dampening/blending these color distinctions. However, most people, regardless of the color range that their monitors have, will not be able to make out the images/characters in the tests above. That is the point of this test – to find someone who can see the color differences.

  65. Jules May Says:

    Sorry to press you on this, but I don’t think you’ve answered my questions.

    This is what I think we agree on: the concept of “primary” colours is more useful in colour synthesis than in colour perception. Be fair: I didn’t mention the word “primary” even once in my post :-)

    What sets a tetrachromat apart from a “normal” trichromat is that they have an extra kind of cone cell, compared with the normal three. I think we agree on that.

    The additional cone cell type that a tetrachromat has enables the owner (or, /possibly/ enables the owner) to discriminate more finely the range of wavelengths which everyone else sees as shades of orange. I think we agree on that too.

    Here’s where I have the problems:

    First: you’re trying to represent distinctions which are more subtle than the average human can see, using a technology which provides only the most rudimentary control over colour. Monitors can display only a small fraction of the colours we can see, so it’s a pretty blunt instrument at best. But worse: If you look at two monitors side by side, you’ll see significant colour differences between their images: if you tip one of them you’ll see a significant apparent colour change as well. Why do you believe that such a crude instrument is capable of even constructing the distinctions you want to measure? (Indeed, lots of monitors provide things like high-frequency filtering precisely to compensate for this crudity – even if you do see an effect, haw can you be sure that it’s not the filter that you’re seeing?)

    Second: a monitor screen synthesises its colours using (what are quite correctly described as) primary colours, but the advantage that terachromacy confers is the ability to distinguish wavelengths. That is, as far as I can figure, the monitor simply can’t create the signal that you hope tetrachromats will see.

    Let me offer an analogy. Let us suppose that you have a visual defect in which some of your green cones are wired to your read cone signal, and some are wired to your blue cone signal. (pretty rare defect, but it’s just a thought experiment!) If you and I look at some red light (I’ll use the names here in their common-sense, conventional meanings), then you and I both see red. Similarly, we would both have a similar experience of blue light. And if we were to look at a mixture of read and blue light, we would both experience the mixture as purple.

    Now, let’s look at some light which is not a mixture, but is a single wavelength midway between the red and the blue. My experience I would describe as green, but your experience would be indistinguishable from the previous purple. You (with your defective vision) could match that “green” light using a mixture of red and blue, even though no mixture of red and blue light would ever give me the green experience.

    Now let’s raise the analogy into terachromacy. A mixture of red and green light both I and a tetrachromat would experience as orange. A monochromatic light whose wavelength was midway between red and green I would experience as orange also. But if tetrachromacy means anything at all, the tetrachromat would experience the mid-wavelength as being qualitatively different to (even if not entirely complementary to) their experience of orange.

    By analogy, no mixture of red and green light will produce the tetrachromat “orange” experience (even though it does produce the trichromat orange experience), any more than a mixture of blue and red light can create the trichromatic green experience.

    I guess my question is: why do you believe it can?

  66. COMALite J Says:

    Another wrinkle in all this:

    From what I understand, most humans are actually tetrachromats, not trichromats, and what you’re testing for is actually petrachromacy, not tetrachromacy.

    There is a fourth “normal” cone type, more sparsely populated than the “blue” cone, which has a maxima well into the near ultraviolet. But because our corneas, lenses, and aqueous humours (and I think vitreous humour as well) block UV, those don’t get triggered nearly as often as the R, G, and B cones. We’ll call this one “U” (for ultraviolet).

    The U range does, however, extend a bit into the high frequency end of the visual spectrum, and this is why we can see true violet (not “purple” or “magenta” — those are caused by triggering both R & B) and indigo as distinct from blue, when stimulated by light in that range (e.g. the dim visible light emitted by a fluorescent black light tube). We can also simulate those colors by triggering R & B with little if any of the U, which is why those colors can also appear on an RGB monitor or CMYK printing press.

    This is similar to how yellow can be perceived from a near-monofrequency sodium light (true yellow, that sits roughly in the middle between the R & G maxima and causes both cones to signal equally strongly) as well as by mixing red and green light (the yellow we see on RGB monitors) or a range of frequencies from red to green inclusive that would include the true yellow (most yellow ink or transparencies, such as the “bug lamps” that encase an ordinary incandescent bulb in yellow glass).

    RGB monitors cannot display true yellow nor violet, let alone the extra primary that “tetrachromats” (pentachromats) would detect.

    On monitors: keep in mind that there are different basic types of monitor technology. At present, the vast majority of computer monitors are either CRT (the former majority, now a distinct minority) and LCD (new majority). These are wildly different technologies (just for starters, CRT phosphors emit light directly under stimulation from a cathode ray electron beam, while LCD cells block or transmit light emitted from a backlight).

    Even under those two categories, there were different technologies. CRT monitors could have any of several different phosphor types with varying chromaticities: various flavors each of EBU, ITU, SMPTE (a standard for NTSC broadcast TV), etc. In fact, the whole concept of “screen savers” was because older CRT RGB phosphors could suffer from “burn-in” if left displaying the same image for too long, and also over time the three phosphors tended to age and dim at different rates, so the same monitor would show different color responses at different times in its lifespan.

    LCD monitors include TN, MVA, and PVA technologies, and variations thereof. With the cheaper TN (twisted nematic TFT) monitors, even a slight different in angle of eyes to monitor can cause substantial color shifts. With the cheapest monitors, even the difference in angle between, say, the top and bottom or left and right side of the display relative to the eyes of the viewer, can result in differences substantial enough to make a solid color desktop look like a gradient.

    There are also true LED technologies (OLED such as in the iPhone and iPod Touch), LED-backlit LCD (the so-called LED TVs from Sharp and Samsung as well as the newer monitors and notebook computers from Apple and high-end monitors from Dell, etc.), and other technologies in the works.

    And with all of them, there’s also the small matter of color controls, both in the monitor itself and in the operating system (Windows ICM, Apple ColorSync, Adobe Gamma, etc.), which are very rarely properly set except in savvy computer graphics businesses that have monitor calibration equipment.

    With all of these variables (where even a single monitor can display differently based on monitor age, electrical input, user head position in the case of TN LCDs [merely slumping a bit in the chair is enough!], color settings in both monitor and OS, etc., let alone the differences between different monitors especially of differing base technologies), and the fact that all of them are still based on only three primaries and cannot even display true yellow or violet but only the RGB synth versions thereof, how can you hope to have a monitor-based test for petrachromacy!?

  67. Internet person Says:

    Let me add my own wrinkle to this story: I am an anomalous trichromat. I.e. I see three colors, but my green is different from the usual green and is closer to red.

    I would expect that if you want to make a test for tetrachromacy, you have to make some hidden letters that I can see but an ordinary trichromat can not.

    I cannot see anything in your images, so I don’t think a tetrachromat with the most common extra receptor (found in 5% of X chromosomes) would be able to see anything. My mom has genes for all 4 cones. Not sure if she has magic color powers. Maybe I should ask :)

    Another comment: Some people are complaining about how colors change from monitor to monitor. I can say for certain that this is no issue for testing color vision. I have created my own tests of my color vision which are very robust across different platforms and monitors. Moreover, although not perfect, many of the tests found online do work even on laptops.

    On the other hand, RBG does not produce the green found in my cones so I am very dubious of creating a test (on a computer screen) that I can pass, but a person with regular color vision cannot. (This is doable on paper with pigments). Testing for the anomalous green with RBG seems analogous to trying to play a C# by hitting C and D on the piano at the same time. Maybe this test is supposed to exploit the very subtle difference between the green gun on a computer and the peak frequency of the cone?

    If you can make a test A that I can pass, but a regular person cannot and a test B that I fail but a regular person passes, then (A && B) is a great test for tetrachromacy.


  68. Will Says:

    To everyone saying they see things in this, it’s the power of suggestion. Computer video cards and monitors output in the RGB format (Red Blue Green), you can see this effect on old TV’s, lookclosely at them and you will see little segments made of Red Blue and Green stripes. Not only would you need a state of the art computer monitor (none that display in the required format are available to the public coincedently, so don’t go saying you have such a monitor), but you would also need a video card that outputs the required spectrum, then that video card and monitor would require a new type of cable connector that has input lines for the extra spectrum. So to put it bluntly there is about a 0.9% chance that someone has all the requirements for this test to work. And even then, this test should have been saved in a lossless format, such as .tga, as jpg would almost completely remove the extra spectrum to save space (the format was designed to preserve size at the cost of quality). So as many people have said, this test is invalid. Anyone saying they see patterns, numbers, letters, shapes, etc are unfortunately the victims of suggestion.

  69. JerryC Says:

    2, 3, 4, right?

  70. Violet Says:

    I loaded the 3 circle pic into photoshop and blew up part of the green circles.

    I will try to post it here in 2 different ways:


    The circles each have different shades and tints to it.

    I would love to have different paint mixed then painted on the wall, and we try to see which is different. I don’t think you could use computers, photos or printed versions unless you knew the computer could display the difference, the camera picked up the difference or the printer was able to create the difference and not group it all as the same for easy printing.

  71. Ken Says:

    My wife sees a gray 8 in the red. I (male) see nothing. I cut’n'pasted this into Paintshop Pro 7 and saw from the histogram that there are slight color differences in two peaks — i.e. looked like I had two mountains with dips in the peak (like volcanoes). I cut the upper peak of one volcano in half to add contrast — I could then see a 7 in the orange circle. My wife looked again after the histogram adjustment — she could see a 7 in the orange and a 9 in the green.

  72. Amy Says:

    The middle one (orange) is a T. Can’t see the red or green ones.

  73. Amy Says:

    I want to clarify that the “T” in the middle one has a lip on each end of the top line of the “T”, and it is slanted like in italics. So it could like like a 7 with a lip on the top-left part of the 7 if you can’t see the right half of the “T”.

  74. Lynn Loftin Says:

    My husband was blue/green color blind. He did not learn of this until he joined the Army. In WWII, he was the first scout in his infantry group since he could distinguish camoflauge better than the other guys. ( I had assumed green paint, cloth differed from green plants to him) When he was in college, he was accused of cheating on a laboratory test because he marked more colors of a spectrum for a chemical than were visible to the human eye. He always claimed he could see more blues/violets than ordinary people, that blues/violets were extremely vibrant to him. He thought his color vision was more of a shift than complete since he could make out reds if they were in large splotches and very red or red orange. He has passed away, but I will check with his daughter and grandchildren. This may answer a puzzle of many years.

  75. Tiara Says:

    I see s – e – e but very faintly.

  76. Aaron Says:

    I do see some shapes in the circles. Like others I won’t say it on here to avoid people “copying” my answers. I’ve always seen the world a little differently than others. It may be something other than tetrachromatic vision though.

    My father is quite color blind and can only really see green colors. He is one that can easily see camouflage and can even tell different types of trees by the hue of green. My mother has vision problems as well. I have good vision and no sign of being color blind.

    I am also male, so according to current research should not be tetrachromatic. I am not claiming to be either. But I do see shapes in your color test.

  77. nathan Says:

    i dont know if i am imagining things, but i see a e in the red one, a t in the orange one, and something like a j, t, or l (something straight or line like) in the third. i am a guy, so this test might not be able to truly test if you are a tetrachromat.

  78. Trini Says:

    Great, now I’m not only short, but I can only see three colors. :)

  79. Adam Says:

    I just see a T in the middle one :S

  80. NOAH M Says:

    well, the one on the right is the most clear… the one on the left is second most clear.. and the middle one is the hardest to tell

  81. grace Says:

    my sister and i saw letters in each circle

  82. Jarrod Says:

    I don’t see any letters, but I see purple, and red in the first circle. I see orange, and brownish black in the second circle. The third circle just looks all green to me. This is probably not what you are talking about, but this is what I see.

  83. dana Says:

    I see lil blue dots in the green circle , and darker curved shapes
    in orange and red circles, no specific letters or numbers.

    I don’t know if a am a tetrachromat, but I am heterochromat :)
    wich means I have different colors in my eyes (green with blue circles and green dots) , not really on the subject but also interesting :)

  84. Marbles Says:

    I could see letters (after staring for a while) but I think it’s just my imagination. We humans construct patterns, even if they aren’t really there. ;)

  85. Carol Says:

    My daughter sees a dinosaur, a 6 pointed star and the side-view of a seagull.

  86. Christine Says:

    I’m pretty sure that I’m a Tetrochromat. My father is colourblind and I’ve always seen different coloured greens than other people and seem to see further into violet and red. However, when I look at your test I’m not seeing anything.
    Who did you work with to create this test?
    Cheers :-)

  87. Kaansker Says:

    Even if you were a tetrachromat or a petrachromat (which is impossible) it is IMPOSSIBLE to receive tetrachromatic vision from any sort of computer monitor, tv or display device.

    Screens are designed to only reproduce a large portion of the RGB colorspace (red-green-blue fundemental colors that most humans perceive). Even the most accurate screens (CRT’s or plasma displays) cannot reproduce the whole RGB spectrum.

    Plus, a tetrachromatic person has a fourth cone cell that is sensitive to light between the red-green spectrum which approximately is ORANGE. Because your computer screen can only display several levels of the orange tone by mixing red green blue, you are not able to perceive anything different than a normal trichromat person by looking at these circles.

    In order for this test to work for tetrachromats, the monitor whould have needed 4 distinct fundemental colours (RGBO= red-green-blue-orange). Thus, the monitor would produce more color tones and shades of orange (imperceivable by trichromats ofcourse).
    Also, the image is in a JPEG format, a lossy compression format that reduces picture quality by removing unperceivable or very low-perceivable colors limiting thus a true tetrachromatic vision.

    People who claim they see some shades, shapes, shadows or varying color tones just perceive these differences because of the variation of the size of the small dots and the variation of the amount of dots that are displayed the given surface. So technically the brain interpretes those variations by trying to assimilate them to signs/symbols or images that seem familiar to you.

    This test really has nothing to do with tetrachromacy.

  88. Lushy Says:

    All I see is a faint “T,” slightly off center, in the middle circle. The other two look empty.

  89. Clockpainter Says:

    I see 9 in the ecru circle, pi in the byzantium circle and a map of the world coloured by algae population density annotated in Manchu in the octarine circle.

    Am I tetrachromatic?

  90. david Says:

    I don’t see any letters but, I do see reds and purples and little blues(red circle), orange yellows browns red and little green (orange circle) green and yellow (green circle)?

  91. Heather Says:

    Only in the first one i immediately saw 19, but that was about it.

  92. Thomas Says:

    First of all, I think the majority of these people are misunderstanding what you’re asking. That, or I am. Are you asking if anyone can see different-colored letters inside each tiny circle within the three large circles? Or, are you asking if there are different-colored letters somewhere within the three large (red, orange, green) circles?

  93. chad Says:

    The auther said “(sadly, no ultraviolet vision, etc.)” The thing is, I can see into the ultraviolet specturm. Every time I look at a rainbow I see extra colors below violet. They are fainter but for me they are definently there. In the three differnt color patches I can’t see any letters or numbers though. So how is this possible?

  94. neff Says:

    I stared long enough that I saw four circles. 2 red and 2 green. differnt shades

  95. Isee 4 circles? Says:



  96. paul Says:

    i see a sort of diamond pattern but its the same in all 3 so it probably dont mean anything

  97. Paul Says:

    Monitor and video card calibration will most certainly be the largest factor in this test. Without a doubt.

  98. Adeline Says:

    I see 3, 4, 5

  99. Aedriel Says:

    I’ve been demonstrated to be a tetrachromat since I was a child and took a color blindness test. I cannot, however, see any figures in the circles above.

    Tetrachromacy allows you to be able to distinguish between different specific wavelengths of light. A monitor carries red, green, and blue lights on it, specifically to stimulate red, green, and blue cones. Since there is no light on the monitor which emits the wavelength necessary to stimulate the fourth cone in a tetrachromat, it is impossible to test for on a computer.

  100. gus Says:

    R O G ?

  101. james Says:

    I see dead people.

  102. Evan Says:

    I can only see a 7 in the orange one.

  103. Brendan Pound Says:

    I can’t see anything in the first or second circle but the 3rd one I can definitely see a blob of something in the middle – can’t make out what it says *shrug* Fairly certain its 2 numbers…

  104. requiored Says:

    I see . . . dead people!

  105. David Says:

    I have this program that dulls blue and does other things to color on the monitor to make it not hurt your eyes, its scheduled to not be on now but i wonder how it would affect this.

    Its called F.lux-

  106. The Pain Says:

    E C O

  107. NEIL FIERTEL Says:

    I dragged and dropped the jpg image and opened it full screen with graphcs software and I see shapes within each of the coloured circles. there is no question of it but they are vague and rather more like a greenish series of dots within the orange for example. I suggest that a much high res image be posted so that one can really see it. For me, it is very visible once enlarged to a larger image…I cannot thus say if it is a valid exercise though I naturally consider myself warned now to stay well away from Kryptonite.. Send me a better one and I will test it again.

  108. JD Says:

    Does it say GOD? its really messing with my eyes when I try to concentrate. Its almost like it is flickering. And I have a widescreen lcd, so it shouldnt do that.

  109. Joe Says:

    There’s an italicized captial T with serifs in the orange circle.

  110. Latj Says:

    I see a wee man in the orange one- he’s pointing at a tiny fellow in the green one who is wearing a dark green ski mask. In the red one I see a globe, but its all messed up and asia is front and center instead of good ole’ USA. huh.

  111. Thread Says:

    There is a perfect T in the middle picture.

  112. Bryan Keith Says:

    My grandfather (maternal) was color blind red/green. I often (over the years) received complaints from roommates for adjusting the computer or television to suit my vision for color. I am (tested) chimeric. This discovered through a little mishap involving a blood test. My father was to be born with a fraternal twin, he absorbed his twin in utero. I am also homosexual. I am curious as to those variables in all of this. I see “R”, “G”, “B” respectively in the circles. When I first studied them, I saw “O”s or circles in each automatically. Once I read all the replies, I went back, blew my browser up to magnify 400% on a 1024 x 800 res. 22″ monitor. I held a paper over the other circles and observed each, alone, in turn. This was when I made out “R” in red, “G” in orange, and “B” in the green. I DO hope that you will write and let me know one way or the other.

  113. inge Says:

    I think i see more then 1 nummer in each color, but i think it’s,
    30 50 80

  114. Jon Says:

    I’m red-green colourblind so that might be why I see it appears to be more orange in the red circle closer to the middle, and just normal red on the outside.

  115. ronisaurus Says:

    number 2 in all 3 of the circles. cannot distinguish the colors, because they are the same lulz ^^ i have a superhuman sizes nose. what does that make me? :D

  116. Bandi Says:

    I see 23 in all the three circles..

  117. Norbert R Says:

    darker yellow-maybe light brown-central circle

  118. Norbert R Says:

    sorry darker yellow-maybe light brown but four circle

  119. thinkblue Says:

    in all colors there are two hands reaching in each other.
    all circles are the same, only the colors are different.

    or maybe its just a try to feel myself different,,

  120. NEIL FIERTEL Says:

    I sent this tri circle target to a number of people and they do not see what I see. I am male and so in theory I ought not to see what I do see but there is no question of it at all..there are differences in colour within each of the three circles within each of the sub units..clear as can be..second note since I received no reply of interest. I will take my tetrachromatic vision and go elsewhere now…

  121. brett Says:

    I’m a guy and I can see some kinda difference in the circles. But seeing it on a RGB monitor didn’t really help me much. I feel as if my brain can just natrually make out these differences.

  122. pengnui Says:

    r they red, yellow and green?

  123. desan Says:

    i did not read all comments so sorry if it was noticed earlier but does this test work on RGB screen?

  124. Alessandro Says:

    Hi, I’m Italian so sorry for my bad english, I’m a student of physics engineering and I study the optics and the technology of monitors (CRT, LCD, plasma…) and the software technology of image compression (JPG….). The test is impossibile to do whit the monitor (trichromatic) and the JPEG compression… Such system delete the useless information for a trichromatic eye, so try whit a uncompressed image but I’think that is always impossible… The monitor and technology are build for trichromatic people so is very difficult to use such apparatous to generate 2 color equal but whit different composition…

    So mr timbotron please think other way to give the test to people! I’d like to try it but no pay for test hehehe thanks and good bye!

  125. Emma Says:

    Well, I don’t really see letters, rather shapes. Here are the colors I see: In the pink circle, I see hot pink, then a matte pink, then light pink circles. In the orange, I see yellow-orange, and then I see a darker orange, more like a very ripe mandarin circles. In the green, I see a dark green and lime green circles.

  126. Kate Gladstone Says:

    I see, from left to right,
    2 3 8.

    Now where do I go to pick up my Tetrachromat Superheroine Badge and/or get studied by science?

  127. Isobel Lloyd Says:

    I can clearly see from left to right
    G O C.

  128. Dan Says:

    Wow I have flawless colour vision and all I can see is a faint yellow
    ” T ” in the orange circle but its like a weird formal typeface.

    The green and red are just …dots… guess I should be happy that I see UV blacklights as a super bight purple colour.

  129. Grepart Says:

    P 1 4

  130. Rick Says:

    left to right…. 5, 3, 2

  131. Michael Says:

    Think about the following:

    In a ‘normal’ person, yellow light will roughly equally stimulate the “red” and “green” receptors. It is also true that a combination of red light and green light can stimulate those same receptors equally so that the brain sees “yellow” when in fact no light having the wavelength that we call yellow is present. It is a common misconception that mixing red and green light creates yellow light. It does not actually do so, but only fools the brain into thinking that there is yellow light. Our color TV’s depend upon this. You can test the difference between different trichromats by varying the mixture of red and green wavelengths that will appear to exactly match the wavelength called yellow, but as yellow itself is atomic, it cannot itself be varied.

    One can project this concept to the problem of producing a method of detecting a tetrochromat with three colors and see why it cannot be done.

    However… There is a brand of television currently being advertised that uses four primary colors: red, green, blue, and *yellow*. As yellow lies between red and green, it may be possible to produce a test for (at least some kinds of) tetrachromaticy that will actually work on such a monitor.

    The ads make no mention of this, however; they just imply that the picture produced will look more real because they are capable of producing a richer color gamut than other televisions.

    The problem with producing such a “better picture” is that you can’t create data from nothingness. One will need a 4 primary color camera to obtain the color mixtures needed to produce images containing the full range of colors that a tetrachromat sees, and the ads do not mention that.

    Furthermore, to properly support tetrachromatic vision throughout all media would require reworking of the infrastructure of color representation. For example, scanners would be known as 32 bit and 64 bit scanners rather than 24-bit and 48-bit, RGB cabling would have to be replaced by RGBY cabling, photographic and motion picture film would need have four appropriately light sensitive emulsion layers, likewise with their digital equivalents, etc…

  132. just passing through... Says:

    Seems to flicker between an “m” and an “O”, depending on if you look “up” or “down”.

    But maybe I’m just seeing what I want to see. I don’t see how an RGB monitor could display these shades anyhow.

    But if you look at the flowers at sunset, you will notice a nimbus of UV light around them. Its subtle at first, like a “pushing out” or “sucking in”. Maybe humans have just forgotten how to see these shades because its not as useful as it would have been in a hunting/gathering context (identifying fruit in the wild).

  133. Taylor Says:

    I see a 2 in the first circle, a 7 in the second circle and a 1 in the third circle.

  134. ringo Says:

    I am a tested tetrachromat (via my eye doctor), I can in fact see into the ultraviolet, and I see nothing in these circles.

  135. Display Myths Shattered: How Monitor companies cook their specs - Hardware Canucks Says:

    [...] in our eyes. Almost everybody. But some women have 4 or are tetrachromat and perhaps some men. Are You a Tetrachromat? | The Tijuana of the Internet Tetrachromacy – Wikipedia, the free [...]

  136. Beth Says:

    Hmm, I don’t see any difference in the colored circles but already know I see the infrared of remotes and also into uv even through polycarbonate lenses so I must be a tetrachromat although no one in my family is color blind. I see a “glow” of bluish-violet in the sky before others see any light pre-dawn. I always know where the sun is coming up. I’ve always known I saw colors differently than most people and can exact match paint colors better than machines as I see something that they cannot distinguish. Obviously, from my name, I am female.

  137. M. Roberts Says:

    There is no problem with the monitor using RGB (or a printed book using CMYK, for that matter) because the 4th cone is sensitive to wavelengths *within* the RGB space. We don’t need a yellow phosphor in monitors to be able to see yellow.

    JPEG compression, however, doesn’t even operate in RGB, it converts the image to YCbCr (and then back again during decompression), which can (and does) alter several colours (typically a 0.4% change just in the conversion, before any compression is applied).

    Also, there is close to 5% variation within each each colour just from JPEG artifacts, which is much higher than the (approximately) 1% “deliberate” variation that the test relies on. As such, it’s unsurprising that so many people report seeing completely different letters or numbers; it’s just “wishful seeing”.

    The only one that appears to have resisted is the middle (yellow) one, and even that is extremely noisy and hard to make out (both naturally and by colour isolation filters. It is indeed an italic serif capital “T”, but I doubt anyone can see it without “cheating”, given the amount of JPEG artifacts. The other ones are simply not there anymore (there’s a lot of colour variation, but it’s just semi-random noise from the JPEG artifacts).

    Although perfect monitor calibration is not absolutely essential, an image for this kind of test cannot undergo lossy compression or any colour space conversions, otherwise the test becomes invalid.

    Note that “cleaning up” this image won’t fix it, since the precise colour information from the original was lost when it was first saved in JPEG format. This kind of image should always be saved in PNG (lossless 24-bit), if it’s going to be put online.

  138. Annie Says:

    I saw a 3 in the orange one, it lasted for about 2 seconds then disappeard, but it was definately a three.

  139. Katrina Says:

    If the goddamn circles would STOP MOVING I could connect the lighter shaded circles together to form something…. but as soon as I move my eyes even a little those little shits start swirling around. >.<

  140. Albert Renshaw Says:

    As clear as day I can see a big capital “T” in the middle circle..
    I don’t see anything else…
    Am I a super-human?
    Please get back to me!

  141. Sam Says:

    Hmmm i can see question mark, question mark, pacman.

  142. Andrei Says:

    I see the number 28 in each of those circles, is this right?

  143. amy Says:

    I’m on a Mac powerbook, and I see maybe some mottling of color in the central areas of the red and orange circles, but no distinct pattern or symbol. I half expected to be a tetrachromat, because my son is colorblind, and I have (or had in my youth) some pretty spectacular vision capabilities… like spotting a four-leaf clover in the lawn at Sea World while walking down the sidewalk with my friends….

  144. Petronius. Says:

    I modified only the Contrast and the Gamma on MS Photo Editor and i clearly see the T in the orange circle.

    Back to your test, this is not a test for tetrachromacy but for the ability of some peoples to differentiate very closed colors. This is not tetrachromacy, as some of real tetrachromat peoples here already tell you.

    Nevertheless, your test is a negative success. Thank you!

  145. Ashley Says:

    I do know that different computer monitors show very different colors. However, even on this one, I do see differences in shades of colors, like in the red one I see straight red, but also red-orange, even hints of greenish hue, etc. I graduated in art, and we were taught to find color in color. I remember seeing green, pink, orange, purple, blue, a variety of colors in a person’s skintone, like literally see it, but only after staring for a while and teaching myself that skin isn’t just skin, and snow isn’t just white, and grass isn’t just green. It’s not an incredibly discernible difference in these colors, but I’d like to think I see colors differently. Sometimes people will say that something is pink when I am so dead set on it being purple, even in 5th grade when us students argued over the color of an iMac haha. I’m not sure though. I would like to know, or have a more definitive test, but if I don’t have it then I suppose I’ll find something else I am superhuman in haha.

  146. Larry Says:


    I’m not a tetrachromat, as far as I know, but I do have a rare condition that bears a resemblance somewhat. (In fact, to my knowledge, there isn’t a name for whatever condition I have.) Basically my visual spectrum is shifted, somewhat. Imagine a window of range, and the entire thing is off to the side. On one end I can see things others can’t, but I suffer on the other end.

    The good:

    I can see in darkness about as well as a normal person can see in twilight. In total darkness I can see a what appears to be a halo-effect aroud people (a soft, whitish hue) that I’m told is ultraviolet, although I’ve never had that proven, so I don’t really know what it is. In daylight I can see shadows that others can’t (too faint for them to discern). And the most bizarre aspect, my eyes sometimes produce luminescence and “glow” in the dark. It’s a family trait we’ve called “cat’s eyes” for decades, even though it’s really nothing like that in effect or appearance. Doctors told me it’s rare, but normal, and is caused by a chemical reaction. I should note, before someone leaps to a conclusion about it, that my being able to see in the dark is unrelated to the luminescence, as that only happens some of the time. Fun to mess with friends, though. Can’t count the number of times I’ve had people see it and run screaming. lol

    It was a pretty common thing for friends to want to test it for themselves, so we’d sit around in the dark, drinking beers and talking, and every now and again one would hold up their hand with X-number of digits fanned out. I’d mumble, “three” or something, and they’d swear aloud and call me a mutant. It was pretty funny, really.

    The bad:

    I’m light sensitive (sunlight can be extremely painful), and I see colors faded, like a poster that’s been in the window too long under sunlight. Not quite colorblind, per se, but it has that effect to a degree. I can see red and green, but colorblind tests label me red/green colorblind about half the time. It’s hard for me to grasp with no frame of reference, but I’ve come to understand that there are things on that “end of the spectrum” I cannot see at all.

    No idea if it’s related, but for many years my eyes would regularly change colors, all over the map, but as I got older (sometime during my thirties) they finally seemed to settle on green most of the time. I’ve also noticed, now that I’m in my forties and my vision is suffering in general, that my ability to see in darkness is beginning to diminish. It’s not gone, by a long shot, but I can tell it’s beginning to get weaker.

    There are some colorblind tests on the internet that, for whatever reason, have things on them that I *can* see that my friends with normal vision can’t, but I don’t remember any specifics. We were mainly just goofing off with some of them, not doing “research” of any sort.

    More than anything I’d just like to finally know if my condition, for lack of a better term, has an actual name, or if it’s just a fluke.

    (On the bright side, it was a handy trait when I was younger for impressing goth chicks and vampire wannabes, lol)

  147. Larry Says:

    Oh, sorry, but I left something out of the above. I’ve learned to ignore it out of necessity, so I tend to forget about it.

    In normal lighting I can also see what appears to be a faint, colorless outline around people. Only on their skin, though, not hair or clothing. It’s barely a couple of centimeters deep, and almost looks like a top layer of skin, although it’s completely translucent. Naturally the new age types all say I’m seeing auras, but I really don’t think so, since if that were the case (and real, which I don’t know about) wouldn’t there be varying colors? Not to mention that, supposedly, people who see auras see them much larger, extending outwards several inches. No, whatever it is, I don’t believe I’m seeing “auras.” Not a clue what I’m actually seeing. My best guess as a layman would simply be that I’m seeing some sort of effect caused by the natural electrical field humans generate. (And if that’s an aura, it sure doesn’t fit the descriptions the new age types have given me multiple times.)

  148. Christina Says:


  149. mouse Says:

    All of you guys that think you are seeing things in the circles are fools. There is no possible way to test for tetrachromacy on a computer monitor because it can only display RGB colors.

    I repeat…


  150. Claire Says:

    I see W, T, F. Just kidding, I don’t see any dang thing except some pretty circles. This could double as a study of people seeing what they want to see… never underestimate the power of your own imagination.

  151. Hannah Says:

    Apparently you actually can’t be one if you are a guy at all, because they have two X chromosomes

  152. maul Says:

    ITT: Morons trying desperately to feel special… and failing fucking miserably.

  153. varun Says:

    C G O?

  154. varun Says:

    wait ultraviolet cant display on a monitor.

  155. Sam Says:

    Not a tetrachromat, but something interesting: when I take off my glasses the red circle looks like it’s glowing like a stoplight.

  156. g Says:

    I don’t think Red-green-blue monitors would work to test this. This is just an educated guess, but I think if I can explain the reasons for this guess clearly, the debate will clear up. I may be wrong, but I think I can explain this side of the argument clearly.

    Normal eye cones detect Red, Green, and Blue frequencies. When we see a color like “Yellow”, it excites both our Red and Green cones, and we perceive it as yellow.

    BECAUSE we have 3 cones in our eyes – Red, Green, and Blue, our monitors have 3 pixel types: Red, Green, and Blue. These pixels mimic “yellow” by exciting both our Red and Green cones, just like real yellow does. However, its just an imitation: what hits our eyes is not ACTUALLY yellow light, just a thorough mix of red and green. Similarly, we are not ACTUALLY seeing white, on the monitor but just yellow, green, and red mixed up. Look closely at the monitor and you will see this is true.

    We trichromats are incapable of seeing true yellow as a species – its just the brain’s interpretation of what the red and green cones excited simultaneously look like. So, its pointless to include a yellow pixel on our monitors when Red, Green, and Blue suffice to make all colors visible to us.

    Now, imagine an alien race which is all colorblind and has no “green” cone. Our green cone is “in between” the alien red and blue cones, so its not that our RANGE is different, but we will be able to DISTINGUISH colors in the “green” spectrum better than they will.

    When we look at the alien’s monitors, there will be no green pixel. They wouldn’t need one to simulate the colors they see. Their monitor will never simulate our green cone. It will be as if we, too did not possess a green cone. A human and a colorblind alien looking at an alien monitor will see the exact same thing. Both the human and the Alien might PERCEIVE green in the mind as an average of Red and Blue, but neither would actually see green (because there is no green pixel).

    Now, an RBG monitor will stimulate the tetrachromat’s red, green and blue cones. It will NOT simulate the tetrachromat’s “orange” cone. Even if the RGB monitor displays “Orange”, the actual wavelengths emitted are only Red, Green, and Blue. Therefore, the tetrachromat’s Orange cone CANNOT BE STIMULATED and it would be just like it wasn’t there. A tetrachromat looking at a trichromatic screen sees EXACTLY the same thing as a trichromat looking at a trichromatic screen, provided that the R, G, and B pixels correspond to the R, G, and B cones…as they probably do, for the sake of maximizing trichromatic color perception.

    The tetrachromat is capable of seeing true orange, while trichromats are not. BUT, with a RGB monitor, both the Trichromat and the Tetrachromat will merely PERCEIVE orange: the trichromate will not SEE orange because he doesn’t have the cone, and the Trichromat will not SEE the orange because there is no orange pixel.

    I hope this clears things up.

  157. ahuxley Says:

    All your base are belong to us?

  158. Kiera Jayy Says:

    i see little rings in most of the tiny dots. they’re kinda bluish, but they are really discernible. i’m no tetrachromat though, that’s too mary-sue for my taste.

  159. Emily Says:


  160. Berlin90 Says:

    i see sort of 3d cube in all three circles

  161. shawna Says:

    so who got it right?

  162. will Says:

    it’s three spades

  163. will Says:

    I’m sorry, i meant clubs.

  164. Rob Says:

    Opened this image in photoshop and compressed the colour curves which makes it easy to see slight differences in the RGB values. The middle has a capital T, but it is even then quite hard to discern because of the jpg compression. Monitors only have 256 intensity values on each channel, and tetrachromats can see “in between” the colours.

    Basically having the image in a lossless format like .png might help, but ultimately monitors cant display the amount of colours for this test.

  165. Andrew de Andrade Says:

    I don’t know the red one, but the orange one is a capital “T” and the green one is a lowercase “i”

  166. Andrew de Andrade Says:

    Oh yeah, and they are in an italicized serif font.

  167. Don Says:

    six pointed star in each circle

  168. Brian D Williams Says:

    I first read about tetrachromats a few years back, then discovered an engineer who made a special set of glasses that enabled those with normal vision to see as a tetrochromat.

    I tried to get Oakley interested in making them and was trying to get the engineer to loan them to Sci-Fi writer Bruce Sterling for an article

  169. Lauren Says:

    I cheated and using photoshop, could quite clearly see a 7 (possibly a T as others have seen, tho it looked more like a 7 to me) in the middle circle, however could not see anything in the other 2.

  170. Asa Says:

    I was catching a couple of letters, one slightly slanted and definitely one smack in the middle of each

  171. Ali Says:


  172. Eric Says:

    Dear Everyone,

    A standard monitor (32-bit color) these days can only display up to 16.7 million colors using RGB SUBPIXELS.

    Meaning, even if you were a tetrachromat (which chances are, you aren’t, because there has only been two cases ever actually considered in history), these tests wouldn’t be able to properly gauge it considering your monitor outputs colors trichromatically.

    I read internet comments from people like most of you all every day; the echelon of self-important douchebags that walk the earth bragging about how your eye color “Isn’t blue, it’s aquamarine” and how your “online IQ test scored you as a 212″ (for the slow out there, these IQ tests are never accurate, get the fucking Stanford-Binet if you want). It’s all bullshit. It’s all a way for you fucking people to feel special; to avoid drowning in your own mediocrity.


  173. aloner Says:

    i guess i saw R in the three circles. screens brightness disturbs u know..
    somthin cool, look at a bright white light for a while and it separates into three colors. red outside, green in the middle and blue in the center. its like auto focus and zoom…

  174. Southern Girl Says:

    I am a High School Student doing a science fair project on tetrachromacy. I was wondering if you had any suggestions for going about the experiment and the acuracy of the above test.

  175. cbadland Says:

    The August 23rd 2010 post by “g” sums this whole farce up: it is impossible to test for tetrachromacy using an RGB device. People who say otherwise either do not understand how the eye works or are confused as to how a monitor creates color. Or maybe both.

  176. YIM Says:

    I can see in the orange a “T” and green a “j”

  177. Harper Says:

    I saw sort of undefined blobby shapes of subtly different colors in each circle; my vision is evidently superior enough to define the colors but my brain is probably not connecting the signals.

  178. Lorna Says:

    um hi.

    i see variations in the red and green circles, though not the orange circle. the more i look at the circles out of my peripheral vision, the more the variations stand out.

    in the green, there is a number 8 that stands out very clearly to me, in the red, there is nothing quite so clear, but still there are anomalies.

  179. Madison Says:

    well guys, all the people who see shapes and letters and numbers within the circles are imagining them. they’re being formed in your mind, not because they’re actually visible. but i digress.

    my father is colorblind, and i am in fact a tetrachromat. i was tested a few years back, and im currently 18 now. and while i have the ability to see colors much better than the average person, i ironically inherited some other vision issues from my dad. but i can tell you for certain that this test does work to some extent, although i think your monitor can have an effect on it. mine happens to be about as high res as they can get, since i see no point in being a tetrachromat and not enjoying seeing the differences other people cant.

  180. michael Says:

    all the different colors actualy started to confuse me. i dont there is anybody who couldn’t see there were more than one shade of ach color. it’s too obvious.

  181. Aiedail Says:

    This won’t work.

    Computer monitors can only project colors in a trichromat’s range.

    I think I’m a tetrachromat =D I have very good color perception, and I can sometimes see colors that others can’t. Example: Everyone says my eyes are plain green, but I can distinctly see several shades of emerald green and a ring of brown in the center. I’m adopted, and I know absolutely nothing about my birthfather’s side of the family except what he looked like when I was adopted and his name. I have a nice chance of being one, and I still don’t know very much about my mother’s side.

  182. Anna Says:

    I can see the word “see” in all of them..

  183. Vicky Says:

    Hi, i read some of the comments about the whole jpeg thing, im viewing this off my phone so i dont know how that would affect the quality BUT I definitely see some color difference. Each dot has a much darker outline around it. The red has a purpleish one, the orange has one which is grern and red, i cant describe it. And the green one has blue, a brownish color, and yellow, again i cant describe it. Also i do see letters inside each dot. They’re not very clear, i cant make out what each individual letter is ( but then im looking at a really small screen ). Also i can see color when i look at a uv or infrared lamp. If i look closely i can see rainbow dots (like pixels) on any surface. Its like i can see every color thats making up the color of what im looking at. Am i a tetrachromat?

  184. bryan Says:

    i can make out an “s” and an “e”

  185. Aiedail Says:

    Also, there are two types of tetrachromacy. L-cone and M-cone, those who have an extra red and those who have an extra green. I wonder if their extra colors are different…? Hmm…What would happen if a tetrachromat or a red-green colorblind had a kid with a red-green colorblind, and their kid got an extra of both colors…??????

  186. Josh Says:

    I don’t know if this has anything to do with the above test but I can see both answers in Red/Green colour tests (colour blind and normal answers, frustrating as hell) is that normal? both my mother and sister (twin) are, i believe, extremely colour sensitive as well.
    I think what im seeing on this test are patterns in the different circle sizes though, not shades, but my laptop is pretty bad so i cant be sure.

  187. Lewis Says:

    Well, I screwed around with it in Photoshop for a while. I finally got a T to show up in the center. I couldn’t get anything out of the other circles. Not sure how this test could be accurate as stated by many others above. I made the letter show up by grossly blowing out the levels and adjusting the RGB color channels. The variance in color is ever so slight. So, it’s interesting if you could see it without any tinkering. I think the test just doesn’t quite work in an RGB environment.

    Here’s what I came up with:

  188. Lewis Says:

    Lean back and look at the center one slightly out of focus, you should see the T. Can anyone see anything else?

  189. Gramma Jean Says:

    My red/green colorblind son called and told me I needed to take your test for tetrachromacy. Okay, the red circle is populated with rose red dots but also with burnt-orange dots, not in any particular pattern, just two subtle shade differences; the gold circle is populated with all gold dots, however, a lot of the dots are more color-saturated than others in the same circle; the green circle appears flat green to me, with no variants. I am an artist, if that means anything. I’ve had a feeling I see the world differently than most people. I don’t think people generally discern the minute differences in color shades or tones, nor are most aware of the exquisite effects color can have on a person’s mood.

  190. Emmanuel Says:

    I can see many colors honestly why is that

  191. Peter Says:

    About performing this test on an RGB monitor…. this should not work. Why not? Because the definition of a primary color is that is cannot be made up by the “other colors” and that is why we need this third primary color to make all colors. For example, you cannot make the primary color”red” by mixing the primary colors”green” and “blue” together. So for tetrachromatic “primary” colors it would not be possible to make the fourth color with a combination of the first three primary colors. As a result a display with three primary colors cannot make a fourth (independent) primary color. I can make all kinds of colors, but not this independent one, since all colors made are just different sums of the three primary colors the display can make/display.

  192. Sid Says:

    If you look at it you will seem something, it happens a lot. its like when you look at what seem to be a bunch of dots and after awhile you see a sail boat. whats being shown in the circles cant be picked up by normal people, but we can stare at it and our brain will try to see a image…for me I see S.O.S.,
    But someone with tetrachromat will see whats really there.

  193. Sean Says:

    I’ve analysed this picture and I can tell you it doesn’t work as a test.

    The JPEG artifacts are a small problem (but easily avoided with PNGs); the fact that it’s stored (and normally also displayed) as red, green and blue channels is a massive one.

    No amount of expanding the hues or sampling the different spots can reveal any useful information. This test needs to be printed with a very particular set of inks.


  194. anonymous_nerd Says:

    I’m trempted to try to search these for patterns to find what characters they might be… I can’t tell by color difference though.

  195. KFLINT Says:

    I see the numbers in the green and orange clearly but have to strain to make out the red.

  196. Bouchard Says:

    Your test: 8 – W – nothing (this is normal for me on the yellow green).


    My name is Celia-Violaine Bouchard, I am a 54 year old woman, a professor of biochemistry and biophysics.

    I’m deuteranopia four-color (purple, red, orange, blue), I do not see the yellow but two additional pigments (purple – orange).

    I am doing private research on color and I also work to develop a battery of tests for the four-color.

    I’m interested in talking with you.


    Celia-Violaine Bouchard

  197. Lamouroux Says:


    Me too … I read “S O S”. On the other hand I know I’m tetrachromats …


  198. Helmut Brunner Says:

    I see figures in the red and orange, not in the green.

  199. Matthew Slyman Says:

    As pointed out by others…

    IN THEORY: The colour-space of ANY RGB-based monitor will make it impossible for this test to work. It doesn’t matter whether it’s a cheap one or an expensive one. If you scanned the test-cards using a trichromatic scanner or camera, or encoded the images using a trichromatic compression algorithm, or display the images using a trichromatic screen; any of these things (most particularly the latter, since one might conceivably design a tetrachromatic screen that attempts to decode RGB signals and re-encode them as RGBX); and you’re finished—your test won’t work.

    Personally, if I was designing a test for tetrochromacity and expecting it to work, I’d print using inks that are based only on one colour chemical (not based on a blend of colours). You’d probably need specially made printer cartridges in a photo printer system (the sort that uses 6-8 primary inks), controlled by custom printer-driver software that doesn’t try to reinterpret the colour space in terms of RGB. Get ready to get your hands dirty with some real low-level colour chemistry, software engineering etc.

    IN PRACTICE: I’m pretty convinced by Mea’s first comment. Proof of the theory, if you like.

    TO ANYONE WHO IS SEEING THE LETTERS VAGUELY IN THE CIRCLES: Sorry but anyone who is subtly “seeing” something other than flat colour is probably just imagining it. After staring at the circles for a while, I began to see very subtle shapes myself… Curiously, the shapes depended on what I believed I saw… So in other words, I saw in a very subtle way, what I wanted to see. If you look hard enough, you can see patterns in the arrangements of the little circles… I think that’s what does it.

  200. Fade Says:

    Black, grey, Blue

  201. Martha Says:

    I see B T and maybe S?

  202. Jessica Troisi Says:

    You are all STILL getting fooled by this shit? I know you all want to be “special” and “different”, but you’re not. No RGB monitor can be used for a tetrachromacy test. You wanna stand out and show the world how awesome you are? LEARN BIOLOGY…AND COLOR THEORY.

  203. Peter Says:

    I just opened the test image in Photoshop, and determined it to be only a highly compressed image with NO hidden characters at all in any channel. Sorry, but if it did indeed have those extra colors, they were lost in this lo-res JPG conversion. FAIL.

  204. lola Says:

    I saw the letter S in the red one and maybe the green one at some point. And what looked like an odd flower shaped doodle in the red one. The shades are definitely different there. And I saw green and red flakes in the orange one. Some of the circles are darker, closer to the red spectrum, and some are lighter, and some look sort of green. The green one was harder to get anything from, at least from my perspective. But I did notice some reddish and orange flecks. I noticed them in an odd pattern sort of like a crane :p Maybe I’m just sleep deprived.

  205. Harry RayGene Pierce Says:

    I see the E in both the Red (easiest)..Orange (perceived next) and Green (ambiguous).. I would like to know more. This is the first tetrachomat test I have taken. PS: this phone was taken via an iPhone 3GS. I hope to hear from you, thank you…^^

  206. Carolyn Lipson Says:

    I see what appears to be a digit 9 in each circle. To me it seems more like an illusion related to the dot pattern than a noticeably different color

  207. Brie Says:

    I saw differences in the orange and green circles pretty quickly but the red one I had to stare at for a couple seconds and then I caught a few differences. The red is the hardest for me to see.

  208. Lili Says:

    In some ways I see 1,3 and 6. In others, there are kinds of kaleidoscopic fractal-like shapes.

  209. Jane Lillian Vance Says:

    Yes–I see other colors.

  210. Kathrn S King Says:

    My wife (after playing with the setting of the monitor and zooming in and out) says she sees ‘8 point star/scallops’

  211. Katherine Says:

    I see the same thing in all three and it is not letters. It is stronger on my laptop than this old desktop I am writing from this morning.

  212. Cecilia Bahena Says:

    I saw circular disks of color (something like an aura) emerge behind, in front, to the left, to the right bottom of the colored circles.
    Lavender-Pinkish by the , Perwirle-bluish, tourquise-greenish. First they were white then they quickly turned into the soft colors.
    As far as the actual color circles I see some sort of animal shapes but that is due to the patterns within them.
    After a minute or so the aura circlular disks began to come in closely to the colored circles making rings around them of another color.

  213. Kai Says:

    Everyone is a tetrachromat on the internet.

  214. Patti Dengler Says:

    My daughter says she sees starfish, especially in the red one.

  215. Anonymous Says:

    There’s an extra thing that you should consider with your test. Some of us can see into the UV range, either due to natural deficiency or surgery. Cataract surgery with the right person can bring it out.

    I had cataract surgery done to one eye (the only one I needed). In that eye, I see black lights as a vibrant purple. Some things, like some purple flowers, look different in each eye. Unfortunately, I haven’t seen a monitor that can reproduce the effect, so no web based test could possibly do it. There’s no reason they should, since most people can’t see it.

    It’s an unusual sensation. Think of hearing two musical instruments, one in each ear. Now if one were slightly out of tune, you’d hear a warble. Imagine seeing it instead. I guess to understand what I’m saying, it would help if you’ve tried LSD at some point, and seen music. :)

    When the surgery was first done, seeing UV was physically painful. Over the years, it has just become a curiosity.

  216. Michelle Says:

    I can see different shades of red and yellow within the yellow circles but it doesn’t form a solid letter and seems to move around a bit. I have a condition called Irlen Syndrome, so I don’t know if that has any effect on it – I’m supposed to have tinted glasses to see properly but currently can’t afford them. My father is red/green color blind though. I also have Aspergers syndrome. I often feel like I see colors that others don’t and describe colors differently than what other people do. I don’t know if that would be related to this or not, but I’m very interested in finding out more about how my eyes work and how I process the information I receive from them.

  217. Lawrence Silverman Says:

    My wife says she saw numbers in the first two, but nothing in the third. I hesitate to publish what she saw online, but if you email me I’ll tell you what those numbers were.

  218. Dina Says:

    There’s no way you can create a tetrachromactic test on a computer. A computer’s colors can never imitate every single color in the world.

    However, I’m interested in this study…

    Ever since I was young (preschool age) my teachers mentioned that I was very sensitive to color.

    My right eye vision is slightly warm toned; my left eye vision is cool toned.

    And my father is colorblind.

Leave a Reply

More Posts You'll Like