Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How good is your color vision?

  1. May 27, 2015 #1
  2. jcsd
  3. May 27, 2015 #2
    That was really hard!!! I got a 7, but I was certain I'd gotten them all correct!
     
  4. May 27, 2015 #3

    lisab

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Whew, that's a tough test! I got 69. Not good, but not surprising - my eyes perceive color differently (left eye vs right eye). My dad is colorblind, and it seems two different kinds of colorblindness run in his family. I have a cousin who is so profoundly colorblind that when he went to a town where the traffic lights are horizontal instead of vertical, he couldn't tell the "go" light from the "stop" light.

    But beware - a color test online isn't accurate, due to variation between monitors.
     
  5. May 27, 2015 #4
    Nice test, 210 here. Could that be why my wife and I have "conversations" about what color that is?
     
  6. May 27, 2015 #5

    Evo

    User Avatar

    Staff: Mentor

    I scored an 8, but towards the end everything was starting to blur together and decided to stop moving tiles although a few seemed like they were very slightly *off*.
     
  7. May 27, 2015 #6

    collinsmark

    User Avatar
    Homework Helper
    Gold Member

    Wow, I got a 0: Perfect score! (with no re-do, i.e., first time)

    I attribute it in part to the fact that my monitor is calibrated. (I use a calibration tool: an older model that is sort of similar to this tool.)

    On a side comment, the OP's implication is correct that computer monitors cannot be used to test for tetrachromacy. Not unless the monitor in question has more than 3 colors per pixel.
     
    Last edited: May 29, 2015
  8. May 27, 2015 #7

    DaveC426913

    User Avatar
    Gold Member

    Wow, I got a perfect score too!

    I knew I had good colour vision (got tested for working at photo labs), but I didn't know it was that good.

    (I suspect attention-span/patience is a confounding factor in scoring. I wonder how many people kept flipping tiles until they though they were perfect, as opposed to flipping tiles until they simply seemed OK.)
     
  9. May 27, 2015 #8

    DaveC426913

    User Avatar
    Gold Member

    I'm not convinced this is true. I see the logic (screens have only RGB colours) but I'm not sure that's required. A monitor can still produce swatches with very subtle grades of blue/green, and a tetrachromat should still be able to distinguish them better than a tri.
     
  10. May 27, 2015 #9

    Evo

    User Avatar

    Staff: Mentor

    My monitor is small and I can't even guess how old it is, 10-15 years? I also have the brightness all of the way down so it won't hurt my eyes. I'd bet no one could score 0 with this thing aside from sheer luck.
     
  11. May 28, 2015 #10

    phion

    User Avatar
    Gold Member

    I scored an 11.
     
  12. May 28, 2015 #11

    collinsmark

    User Avatar
    Homework Helper
    Gold Member

    Allow me to explain two sides of the same coin that demonstrate the limitation:

    Case A)

    Consider a particular, hypothetical RGB color monitor that generates color by combining different combinations of red, green and blue, and that the bandwidth for each fundamental pixel color (red, green or blue) is very narrow. For example, suppose that a given color is produced by using different combinations of narrow bandwidths peaking at 450 nm (blue) 510 nm (green) and 700 nm (red). The monitor would be able to generate very smooth (perceived) transitions between 450 and 700 nm by using different combinations of these three colors.

    But this is partially accomplished due to limitations of the human eye. For example, to generate a typical yellow color, the monitor combines 510 nm (green) and 700 nm (red).

    The (normal) human eye cannot tell the difference between that combination and an actual, single wavelength at 570 nm. If you were to take a 570 nm, yellow color filter, it would transmit a narrow 570 nm chunk of sunlight that (normal) humans couldn't distinguish from the monitor's yellow color (made by adding two individual wavelengths). And ironically, this 570 nm, yellow filter would completely block out the yellow color from this hypothetical monitor.

    But a prism can tell them apart! Separate the colors using a prism or a diffraction grating, and the monitor's light would still form two, separate peaks in the rainbow: one at 510 nm and another at 700 nm. However the 570 nm yellow filter, filtering sunlight, would produce a single peak at 570 nm.

    Humans (at least typical humans) cannot tell this apart, but certain other animals can. If we want an instrument to test whether a being can tell the two apart, the RGB monitor alone is not capable of producing both.

    Case B)

    The bandwidth of a fundamental pixel color (red, green or blue) of a typical monitor is not necessarily all that narrow. A monitor transmitting pure green will produce a spectrum peaking at around 510 nm, but with a wider rolloff, compared with the hypothetical, narrow bandwidth discussed above.

    With the wider bandwidths it is conceivable that combining a wide 510 nm spectrum with a widish 700 nm spectrum could sum to a wide spectrum with a single peak at 570 nm (yellow).

    But then this monitor would not be capable of producing narrow bands of any particular color; not even the primary, fundamental RGB colors. If we were to test whether a being is capable of distinguishing between narrow wavelengths, again the monitor is not capable of producing them.

    Food for thought):

    http://theoatmeal.com/comics/mantis_shrimp
     
    Last edited: May 28, 2015
  13. May 28, 2015 #12

    Evo

    User Avatar

    Staff: Mentor

    I *LOVE* your avatar, what class, charm and grace!
     
  14. May 28, 2015 #13

    phion

    User Avatar
    Gold Member

    Thank you, Evo. I'm glad you like it. :smile:
     
  15. May 28, 2015 #14

    lisab

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    *wonders if DaveC was reading my mind while I was doing the test*
     
  16. May 28, 2015 #15

    DaveC426913

    User Avatar
    Gold Member

    Sort of. More like reading my own mind. :smile:

    I realized after I'd taken it that I had spent as much time on it as I'd needed to ensure I got the best result possible. I often don't do that, and I imagine most people don't. I made several passes, flipping just one tile one space and checking it, until I was sure.

    So I suspect my results had more to do with patience/motivation than visual prowess.

    I would bet dollars to doughnuts your score would drop considerably if you tried it again and spent more time on it,
     
  17. May 28, 2015 #16

    DaveC426913

    User Avatar
    Gold Member

    I think you're over-examining it though.

    A tetrachromat should be able to distinguish between RGB values 0,191,193 and 0,193,191 (two shades of teal). There's only three colours being transmitted there, but the tetrachromat's extra near-green cones will see the second one as more green and less blue, so they will see two different shades, whereas someone with only one set of green cones will not have enough resolving power to distinguish them.

    There's nothing special about their vision when it comes to perceiving narrow frequencies; simply put, they have a ability to distinguish finer gradients of blue-green than others - regardless of how the colours are rendered.
     
  18. May 28, 2015 #17

    collinsmark

    User Avatar
    Homework Helper
    Gold Member

    It might be best explained with a picture.

    Figure 1 shows two types of "yellows" that most humans find indistinguishable. If an animal had a type of cone that could detect the 570 nm wavelength in isolation, it might perceive an entirely different color than the yellow humans see by combining red and green light. In that animal, the two "yellows" could be as different of colors as humans perceive green and magenta differently. And that doesn't even address the other possible color combinations with existing colors.

    It is not possible for an RGB monitor (narrowband or otherwise) to produce the 570 nm type of yellow in isolation of the Green+Red type of yellow. With narrowband primary colors, the 570 nm type "yellow" is impossible to produce (with RGB) at all. With wider bandwidth primary colors it can be produced, but not in isolation.

    This doesn't specifically apply to human tetrachromats only, btw, but rather to color perception in general, to animals limited to certain sets of cones, and how that relates to monitors limited to RGB.
    RGB.jpg
    Figure 1. Humans (typical humans) find these two "yellows" indistinguishable.

    The yellow used here is just one such example. (Cyan would be the next easiest example.)

    There's a whole rainbow of other possible color perceptions for animals having more than three cone types.

    [Edit: corrected a typo in the attached figure (originally had 470 nm for yellow rather than 570 nm). Oops. Also, added some text expanding on the ramifications of Figure 1.]
     
    Last edited: May 29, 2015
  19. May 29, 2015 #18

    DaveC426913

    User Avatar
    Gold Member

    I understand all that.

    What does it have to do with RGB monitors making poor test equipment for tetrachromats? (Which was the original issue.)
     
  20. May 29, 2015 #19

    nsaspook

    User Avatar
    Science Advisor

    Not too bad, 16 before finishing the morning coffee.
     
  21. May 29, 2015 #20
    Once I sized up the task, I saw that a good score would require more than usual care, and that's what I put into it. Regardless, it is quite possible you put even more care into it than me, and that, if I did it again, I could get a better score by being yet more careful. But that would seem to defeat the purpose of the test. That is: I'm assuming a person with really good color vision wouldn't need to take extraordinary care: the differences between one tile and the next would be more obvious to that person.

    What I'm saying, I guess, is that it shouldn't be a test of who can take extraordinary care or not, but about who naturally and effortlessly sees fine differences.

    It could be there is no such person and that the perception of fine differences is always about training yourself to notice them. I don't know, and maybe the creators of this kind of test should sort that out first.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How good is your color vision?
Loading...