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Why we're blind to the color blue

calebkruse.com

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Re: Why we're blind to the color blue

#41

Post by codetrotter »

mrob wrote: post #33
crazygringo wrote: post #19

I don't believe the blurred images at the end have anything to do with eye focus, as the author suggests. After all, chromatic aberration is blurring of only a very, very small amount. The demonstrated seemingly negligible perceptual effect of blurring blue to a huge degree in a multicolor image doesn't seem to have anything to do with that, but rather the fact that we perceive primary blue as a much darker color tha…

See the very low coefficients for the blue channel when converting (gamma-compressed) RGB to luma. E.g. the common Rec. 709 standard assigns only 0.0722 weight to blue. Y' = 0.2126R' + 0.7152G' + 0.0722B'

Did you mean to respond to another comment in this thread where they were talking about YUV? Your comment does not make much sense to me here but would make more sense to me there.

Re: Why we're blind to the color blue

#42

Post by mrob »

codetrotter wrote: post #41
mrob wrote: post #33

Earlier quoted context omitted.

See the very low coefficients for the blue channel when converting (gamma-compressed) RGB to luma. E.g. the common Rec. 709 standard assigns only 0.0722 weight to blue. Y' = 0.2126R' + 0.7152G' + 0.0722B'

Did you mean to respond to another comment in this thread where they were talking about YUV? Your comment does not make much sense to me here but would make more sense to me there.

Luma is an approximation of perceived brightness. All the conversion formulae weigh blue substantially less than the other primaries. This supports crazygringo's assertion that "we perceive primary blue as a much darker color than primary red or green".

Re: Why we're blind to the color blue

#43

Post by anamexis »

codetrotter wrote: post #41
mrob wrote: post #33

Earlier quoted context omitted.

See the very low coefficients for the blue channel when converting (gamma-compressed) RGB to luma. E.g. the common Rec. 709 standard assigns only 0.0722 weight to blue. Y' = 0.2126R' + 0.7152G' + 0.0722B'

Did you mean to respond to another comment in this thread where they were talking about YUV? Your comment does not make much sense to me here but would make more sense to me there.

It makes sense to me here - GP discusses how we see perceive blue as a dark color, and parent comment corroborates that with a low luma coefficient for blue.

Re: Why we're blind to the color blue

#44

Post by skunkworker »

abeppu wrote: post #36

There's an optometry place in my neighborhood with a back-lit sign with big, blue block letters. And every time I walk by at night I note how fuzzy it looks. I'm convinced this is an intentional troll. This optometrist knowingly picked a sign to make people momentarily question their vision.

This happens every wintertime for me as blue string lights are put up, and they always appear “fuzzy” compared to other colors.

Re: Why we're blind to the color blue

#46

Post by aaroninsf »

The use of "blind" in the title is problematic in several serious ways, not least, for being obviously false for any conventional interpretation.

Idle comment: were divergent focal point such a significant issue for visual perception, IMO we could anticipate it would be widely applied by evolution, and we would see many prey species hiding inside blue blurs. There are innumerable reasons this is not the case; but that it isn't is one more problem with the conjecture.

Re: Why we're blind to the color blue

#47

Post by aidenn0 »

klodolph wrote: post #25
seunosewa wrote: post #16

I'd like to see what happens when the red channel is blurred. Digital images like JPGs seem to blur the red channel more than the blue and green channels.

JPEG transforms the color into YUV channels. Y is the luminance, equal to R+G+B or something like that. The U&V channels (color) are often downsampled.

Y is basically "mostly green, a bit of red and hardly any blue" rather than a flat R+G+B. So blurring the green channel (as TFA does) is nearly equivalent to blurring the Y channel.

Re: Why we're blind to the color blue

#48

Post by ihojman »

easy physics question here: if the light converges in one focal point after passing through the lens, as pointed in the 2nd animation, that means that the outer light beams reach that point latter in time than the inner ones, right? My point is that at the same speed, they are traveling longer distances, and the animation does not show that, but that they get to at the same time.

Re: Why we're blind to the color blue

#49

Post by SomeHacker44 »

Alas, this situation is even worse if you have an astigmatism, which blurs the blue more than the other colors. I had an astigmatism my whole life (although my near/far vision was otherwise fine), and the invention/popularization of blue LEDs has been a constant source of irritation.

Unfortunately, this effect is even worse if you wear glasses (as described in the article), which I have done for about two decades now.

And even more unfortunately, it is even worse with the shift to progressive lenses (due to age-related presbyopia) in my experience. It has gotten to the point where all my computers are configured to use blue sparingly, and almost never in pure blue color. For example, there is no blue in my IDE color schemes anymore, and any mostly blue color is made magentaer or cyaner.

Re: Why we're blind to the color blue

#50

Post by drcongo »

One of my favourite series in art is Yves Klein's blue work. For anyone unfamiliar, he found a blue that he considered the bluest possible blue [1], and went on a journey painting everything in that blue. I loved that he did this, and then eventually managed to get to an exhibition of his work at the Tate Modern and was absolutely blown away by it - it really needs to be seen in the flesh to appreciate it. There's something about his blue, that when painted on to a sculpture, almost makes the 3D disappear and the sculpture looks 2 dimensional. Extremely beautiful.

As a side note, some (many?) cultures around the world have no word for blue, blue is just other shades of green.

[1] https://en.wikipedia.org/wiki/International_Klein_Blue

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