Why we're blind to the color blue • Hacker News Board

Re: Why we're blind to the color blue

#151

Post by jdashg » Fri, Jul 16, 2021, 11:49 PM UTC

ywain wrote: post #132

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'

This is basically the same as the Y component used in JPEG, right? Could the phenomenon described in the article be caused by the fact that they used JPEG images? I.e. would we observe the same thing happen with raw/uncompressed images?

No, it's not an encoding artifact.

Re: Why we're blind to the color blue

#152

Post by jcoq » Fri, Jul 16, 2021, 11:57 PM UTC

mtdewcmu wrote: post #128

jcoq wrote: post #77

Earlier quoted context omitted.

I agree. Further, almost all of the blue channel in this image is from the white clouds or nearly black water. There's no other major source of blue.

What would be the result if you flipped the colors, so that the sharp elements are blue and the ocean is red or green?

That's an interesting thought but unfortunately I'm travelling.

One thing is that the ocean is hardly blue. Not sure why my eyes register it as such, but it's mostly very close to black with nearly equal parts of red and green, at least the parts I sampled. I think a certain amount of this article's claim is predicated on the reader erroneously believing the ocean should become blurry.

Re: Why we're blind to the color blue

#153

Post by usefulcat » Sat, Jul 17, 2021, 12:03 AM UTC

sgtnoodle wrote: post #133

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…

I dunno, but when I look at glowing blue signs and blue Christmas lights at night, they look significantly more fuzzy than other color lights.

Also the blue LED on a PS3. Those always looked blurry to me. It’s especially obvious because of the adjacent green LED.

Re: Why we're blind to the color blue

#154

Post by dalmo3 » Sat, Jul 17, 2021, 12:27 AM UTC

sgtnoodle wrote: post #133

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…

I dunno, but when I look at glowing blue signs and blue Christmas lights at night, they look significantly more fuzzy than other color lights.

> At long last, we can see why the human eye can't focus on blue light

At long last indeed. For decades I wondered why blue lights are disturbingly blurry at night, to the point I'd rather not look at them. I always thought it was just me since other people didn't seem to care as much.

Re: Why we're blind to the color blue

#155

Post by Talanes » Sat, Jul 17, 2021, 12:34 AM UTC

washadjeffmad wrote: post #117

techrat wrote: post #106

Earlier quoted context omitted.

'eye prescription'? Bruh. Read the comment of mine you replied to. 20/10 and 20/13 vision. I don't need prescriptions.

That's like saying you can run a 3 minute mile so you don't have a shoe size. This whole thread is silly.

Shoe size is an inherent byproduct of having feet of a certain dimension. A prescription has to be prescribed.

If we're doing dumb analogies, it's like you're trying to insist a homeless man must have an address.

Re: Why we're blind to the color blue

#156

Post by civilized » Sat, Jul 17, 2021, 1:12 AM UTC

bacan wrote: post #146

This article is false. Try this out Photoshop and not even close. Here are my results, with a 22px Gaussian Blur on the Channels https://imgur.com/a/AS0LAyk IMO The only reason the blue appears a little less blurry is that most of that color is in the water & clouds. Not in the land masses, with the sharp borders

Nah, the one where blue is blurred still looks the sharpest. And you blurred them all very little so no surprise they look less different.

Re: Why we're blind to the color blue

#157

Post by mmaunder » Sat, Jul 17, 2021, 1:20 AM UTC

Lots of doubt in the discussion here. I found this, and it’s not quite as elegant an explanation, but it seems to agree that it is due to chromatic aberration and the eye being tuned to focus on red and green light.

https://www.thenakedscientists.com/articles/questions/why-ar...

Re: Why we're blind to the color blue

#158

Post by smusamashah » Sat, Jul 17, 2021, 1:23 AM UTC

jbmny wrote: post #91

smusamashah wrote: post #65

Earlier quoted context omitted.

I got dry eyes some time ago. Dryness gone but now I see starburst at night in headlights, neon signs and stars. Being unable to see stars as flickering dots anymore hurts me the most. Neon signs in particular if blue are totally whacky and unreadable until I go too close. I went to optometrist recently and they didn't understand why blue in particular and recommended a color blindness test which I obviously passed.…

May I ask how exactly your dry eyes led to degradation in vision? I've recently been struggling with mild corneal abrasions that leave me with something resembling a "starburst" in my night vision, and I'm suspecting it may be caused by dry eyes.

I think dryness did some damage on cornea. It's better some rare days (which feels like a beautiful dream) but mostly I see lights, moon, stars any bright light with dark background as starburst or multiples. Even moon :(

Re: Why we're blind to the color blue

#159

Post by mmaunder » Sat, Jul 17, 2021, 1:27 AM UTC

drcongo wrote: post #50

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 so…

Amazing, thanks for the pointer to Yves Klein.

I’ve seen blue man group live and they have an otherworldly look in person, and I suspect it’s related to this phenomenon.

I really like his combination of blue and grey images.

Re: Why we're blind to the color blue

#160

Post by perl4ever » Sat, Jul 17, 2021, 1:45 AM UTC

tcmb wrote: post #69

jbluepolarbear wrote: post #63

Earlier quoted context omitted.

I’ve never met anyone without some astigmatism; especially, people with other vision impairment. Astigmatism is the number one cause of night blindness which is what you described.

HN is so funny. 'I have no astigmatism.' -- 'Sure you do!'

There were three people involved in that exchange, not two, assuming nobody's using multiple aliases...

crdrost described their vision problems, jbluepolarbear said "you have astigmatism", techrat popped in and said "[I have] no astigmatism" and jbluepolarbear made a more general statement that most people do.

I'd assume techrat doesn't know anything about crdrost's vision either.