Comment by rotidder
2 years ago
That exactly is the point of the test though. Not to test whether most people call 100% blue blue, or 100% green green. It is to test at which point of the "inbetween" colors people switch from blue to green or vice versa. It forces you to decide whether the color you see is "more blue" or "more green", since after all they're all just a mix of blue and green.
Well for me, personally, blue and green are simply not adjacent, so there's no point where green turns to blue without going through an intermediate color. This might well be due to my extreme exposure to computer colors, where the in-between color is usually called cyan, or sometimes teal or aqua. When I see cyan, I cannot sincerely say that it looks “more blue” or “more green” to me, any more than an orange tastes “more apple” or “more banana”.
Light can absolutely be more blue or more green in an objective sense. Either it is closer to blue on the spectrum or it's closer to green. It doesn't matter if you have intermediate categories in between.
To poke a whole in your analogy, a more apt comparison would be to a gradient of sweetness, where one can indeed describe a flavor as "more sweet" or "less sweet" relative to apples and bananas.
The whole point of the test on this website is to judge subjective color perception, so I'm gonna go out on a limb and say you missed the point of my comment.
I suspect that if you were shown two blue-green colors side by side, with nothing between them, you could look at the boundary and tell which side contains more blue.
You can estimate that if you can determine at which point the color becomes too ambiguous to call blue on one side, or green on the other. Different people will have a different range. If you want to identify a threshold, you can take the midpoint of the range.
Either of these approaches may be bad. The third paragraph of this page explains why:
https://en.wikipedia.org/wiki/Two-alternative_forced_choice
My suggested approach might not be much better though; it still relies on presenting a single stimulus.
It's not clear how the two-alternative forced choice can be used to find someone's blue-green threshold.
I think a better experiment would be to show the user gradients and ask them to move a bar to where they think is the midpoint in the blue-green transition. Subsequent gradients center on the user's previously identified midpoint, but zoom in more.
There is also this question: by which path do we interpolate from blue to green?
Let's imagine the CIELAB color space. Say that our pure green lies on the red-green axis, all the way on the green end. Blue lies on the extreme of blue-yellow. Do we interpolate through these linearly or what? And using what luminance value?
I suspect that for every given, fixed luminance value, the blue-green boundary is a contour. There are many paths we can take between blue and green, and along each path there is a boundary point. If we join those points we get this contour. Then if we do that for different luminance values, the contour becomes a 3D surface in the color space.
In my case, and it seems OP's as well, it forced me to stop the test instead of picking one of the two.