4 years ago by crazygringo
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 than primary red or green, and we perceive differences in lighter colors much more easily.
If the author were correct that we have big problems focusing on blue, then we'd see that blue text against a black background would be massively blurry -- but it's simply not. It's comparatively low-contrast (because blue is a dark color), but it's nearly indistinguishably as sharp as red and green.
4 years ago by GuB-42
Right, I picked the "blurred blue" and "blurred green" pictures, converted them to grayscale using luminance and "blurred blue" still looks sharp and "blurred green" still looks blurry.
If it really was the effect of blue light, the effect should have disappeared by converting to grayscale.
It is well known that luminance matters much more than color when it comes to perceived sharpness. Digital and analog video exploit that by encoding color at a lower resolution (chroma subsampling). And blue only accounts for less that 10% of luminance while green is around 70%. You may find different values because color spaces are a mess but that's the general idea.
4 years ago by Retric
Thatās not an apples to apples test because of how greyscale is computed. Try swapping the blue and green channels rather than converting to greyscale.
4 years ago by skupig
I think for a proper comparison, you would need to swap them by perceived brightness (luminance), not just the RGB value. You can't do that here because the green channel in this image is out of the possible range of luminance you can achieve with blue (in any standard color space, probably).
Which really illustrates why TFA doesn't make any sense- our eyes are less sensitive to blue, so the contrast provided by max RGB value blue is going to be completely drowned out by red and green if the source of your contrast is white on black.
Here's what it looks like with all channels shifted to have the same luminance: https://i.imgur.com/AnKNdfX.jpg - note it is perhaps a little softer as the peak brightness is closer to black.
Now here's what each channel looks like blurred by 2.5px: https://i.imgur.com/XzVWeZg.jpg https://i.imgur.com/LB5JArJ.jpg https://i.imgur.com/jf4ntth.jpg
They're all clearly fuzzy in comparison to the un-blurred image. The answer to "why we're blind to the color blue" is not chromatic aberration (although it could be a contributing factor, maybe even why we have less blue receptors), it's that we're less sensitive to blue and therefore contrast is usually defined by red and green.
4 years ago by analog31
There's a difficulty with testing perceived color by using a computer display, which is that the "blue" is the spectrum of the blue pixels, whereas the "blue" receptors in your eye may have a different spectral response.
Where I've noticed weird things with blue are with blue sources that have fairly short wavelengths, such as some of the blue LEDs used in Xmas tree lights, and the old blue lights that were on police call boxes. Both of those are very hard for me to focus on.
4 years ago by moralestapia
>such as some of the blue LEDs used in Xmas tree lights, and the old blue lights that were on police call boxes. Both of those are very hard for me to focus on
This happens to me as well and I though I was becoming blind (to blue light) because of my heavy use of monitors/"white" light, etc...
4 years ago by bacan
This article is false. Tried this out Photoshop and not even close.
Here are my results, with a 22px Gaussian Blur on the Channels
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
4 years ago by mrob
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'4 years ago by bioplastic
Indeed, green contributes more. Example of the Y channel after blurring r/g/b: https://imgur.com/a/3p15Qe1
And colured versions: https://imgur.com/a/Knq2Ue3
(image source: https://en.wikipedia.org/wiki/Flower#/media/File:Flower_post...)
4 years ago by rob74
More, as in 10 times more for green, and 3 times more for red. So it's true that we're pretty blind to blue, just the "focusing" explanation is not correct...
4 years ago by ywain
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?
4 years ago by jdashg
No, it's not an encoding artifact.
4 years ago by codetrotter
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.
4 years ago by mrob
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".
4 years ago by anamexis
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.
4 years ago by sgtnoodle
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.
4 years ago by Wistar
Yes! I have difficulty with some blue signage and especially with certain intense blue LED lights as they seem to vibrate to my eyes. I also find it hard for me to read the text in blue on the small, scrolling LED signs common in storefronts.
4 years ago by dalmo3
> 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.
4 years ago by glenngillen
Iāve found my people! I have similar issues and nobody Iāve ever spoken to about it seems to have the same experience.
Two similar issues Iāve had, and Iāve wondered if theyāre related, are:
- at conferences with very large overhead projection sometimes the setup produces an effect where each time I blink itās like it separates the RGB elements. Itās like a combination of being able to see the refresh rate (like when a CRT was filmed out of sync) and the colours being projected out of alignment. - a stadium near me as those digital display advertising signs around the sidelines. If Iām not looking directly at them they appear to flicker. Which actually makes watching a game at that venue not enjoyable as watching the action means I have a permanent shimmering right on the periphery.
Does anybody know whatās happening with either of these?
4 years ago by PepPizzazz
I hated blue christmas lights because of this. Also, I couldn't read the time on the stove from any reasonable distance since it used blue LEDs.
After LASEK, though, I can see blue LEDs nearly as clearly as everything else. My eye surgery gave me nearly 20/10 vision and the greatest thing I got from it was the ability to read the stove clock from across the room. Lol.
4 years ago by tokamak-teapot
I had a car with blue and red illumination in the dashboard. It always felt like I couldnāt see it properly - like it was blurred.
While I like the colour combination, my next car had orange displays, which always look sharp.
4 years ago by usefulcat
Also the blue LED on a PS3. Those always looked blurry to me. Itās especially obvious because of the adjacent green LED.
4 years ago by farbissina
You are so right! I always assumed it was the LED's problem until I started reading all these comments. I think I remember the PS2 having the same thing.
4 years ago by lenkite
Does this only affect people with Blue eyes ? As someone with utterly black eyes, I don't have a problem looking at glowing blue signs and don't find them fuzzy either.
4 years ago by lm28469
Eye color doesn't matter in vision, it's not part of the optical path, its role is the same as an aperture on a camera lens.
4 years ago by sgtnoodle
I have mostly brown eyes, so no?
4 years ago 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.
4 years ago by archduck
Yes!! The lack of green-blue distinction is prevalent enough in linguistics that the term "grue" has entered the lexicon.
Paul and Kay (1969) argue for a linguistic universal which posits that the set of which colors a language has is a function of how many colors it has. (Stealing from https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_...):
1. All languages contain terms for black and white. 2. If a language contains three terms, then it contains a term for red. 3. If a language contains four terms, then it contains a term for either green or yellow (but not both). 4. If a language contains five terms, then it contains terms for both green and yellow. 5. If a language contains six terms, then it contains a term for blue. 6. If a language contains seven terms, then it contains a term for brown. 7. If a language contains eight or more terms, then it contains terms for purple, pink, orange or gray.
The opposite of the grue phenomenon exists too, i.e. languages which subdivide the "blue" part of the spectrum into separate lexemes. In Russian, for instance, goluboy = light blue, whereas siniy = blue to dark blue. This morning I was reading the Wikipedia entry for color revolution, and there's a quote from Belarusian President Lukashenko, "They [the West] think that Belarus is ready for some 'orange' or, what is a rather frightening option, 'blue' or 'cornflower blue' revolution." I had to chuckle about that - it sounds so goofy in the English translation, but that's only because we don't have a lexical distinction there. (Now I would have personally translated it to light blue, but that's another matter.)
4 years ago by drcongo
Fantastic post, thank you!
4 years ago by wchar_t
And I thought grues were the furry adventurer-eating dungeon-dwelling horrors!
4 years ago by selestify
As someone who hasn't seen it in the flesh yet, and doesn't "get" modern art unless someone explicitly spells it out for me, could you elaborate more on why it's so spectacular?
For example, Blue Monochrome [1] seems to my uneducated eye to be just a layer of pure blue that every wall painter recreates every time they paint a wall blue. Why is the Blue Monochrome piece more than just a wall painted blue?
4 years ago by pjc50
Klein blue is outside the color gamut that can be represented on normal monitors, so it's physically impossible to get the full impact of it through a picture. It just looks .. deeper.
There are a few flowers that have this property; fuscias, and others with strong UV fluorescence.
4 years ago by WhompingWindows
Consider the time period and the historical context. It's modern times, Cold War is occurring, and WW1 and WW2 left scars across Western Europe and caused major changes in the art world, including being a boon to abstraction and fragmenting styles into many eclectic directions.
Chemistry has DRASTICALLY altered painting from the Renaissance to the World War era. New pigments have been constantly highlighted and displayed in artwork. Finally, an insanely blue blue has been invented, bluer than any other blue paint in the past.
The artist highlighted above attempts to showcase the new technology in its purest form. Though, despite this strive for purity of blue, the application is inherently uneven. If you look into the painted canvas up close, you will see imperfections and patterns in "just a wall". It's also a statement, it may cause reactions and cause viewers to question the boundary between art and not-art.
It's not my cup of tea compared to masterworks of Van Gogh or Homer or any of the legendary painters, but art goes through many phases and is used to express many different ideas. What I do think is bonkers is that modern artists (who are well-connected) may be paid millions of dollars for these works, which to me don't showcase skill and talent, but which reward creative ideation and concepts.
4 years ago by jdmichal
> Finally, an insanely blue blue has been invented, bluer than any other blue paint in the past. The artist highlighted above attempts to showcase the new technology in its purest form.
I was thinking something along these lines. Based on the first Wiki article, Klein was involved in developing this pigment. If so, the work stands on the merits of that achievement alone. He was, for that moment, literally the only person in the world that could have created that painting.
4 years ago by lmohseni
Thereās a really great short story by Alistair Reynolds about an artist thatās obsessed with a certain Zima blue (name of the story) which is essentially an extended meditation on the above, I think you might like it. :)
4 years ago by drcongo
There's some great answers to your question below, but I'll add mine anyway. Because of the way our eyes see blue (as highlighted in the OP), and especially Yves Klein blue, it has some slightly magical properties in art. The flat blue canvases are absolutely uninspiring at first glance, but stand in front of it for 30 seconds and it starts to recede - it becomes hard to tell how far away the canvas actually is. You're unable to make out texture on the surface because the brain is struggling to actually work it out. It's most striking on the sculptures though, they almost entirely lose their depth and become a flat thing that changes shape as you moved around it. Imagine a 3d rendering of a gallery scene where there's one model that is untextured and unlit - it's like a brilliant blue silhouette.
I took my then 5 year old daughter to the Tate for the exhibition and it had the same effect on her, while almost everything else on show had no effect at all. The only other thing she loved was Bridget Riley, and I think Yves Klein's blue work is somewhere in the same realm - the art is in defining something that makes the viewer's brain do some of the work, that is going to be experienced slightly differently by everyone who sees it.
4 years ago by jessejmc
Don't know about Yves Klein specifically but remember seeing this video from Vox:
"Why these all-white paintings are in museums and mine aren't" [1]
4 years ago by ameetgaitonde
I like to wander around art museums, and on one visit, I shared a gallery with what seemed like a private tour group.
One woman was conducting the tour for three people, when they stopped at one of these all-white paintings.
She was describing the potential meaning behind the work, and noted that sometimes the artist expresses textures, or covers some background work.
It's hard to describe, but I felt this sort of absurdist joy when I watched all four of them lean in very closely for half a minute, only to discover absolutely nothing unique about the work in its texture or color.
Maybe sometimes art isn't made for the observer, but the observer's observer.
4 years ago by pier25
Great anecdote!
Reminded me of the short story Zima Blue by Alastair Reynolds (which was adapted into an animation short on Netlifx's "Love, Death and Robots").
4 years ago by thom
I found that episode very moving. It captured the feeling I suspect many of us experience, of having started out with simple, blissful naivety, before slowly accreting layers of grown up, professional bullshit until a craft loses its joy. The desire to strip it all away, not just the ways in which your work has changed over the years but also the ways in which it has changed you.
I had no idea Alastair Reynolds was behind the story, Iāve enjoyed his work quite separately.
4 years ago by the_af
Apparently more than one "Love, Death + Robots" episode was based on Alastair Reynolds' work. "Beyond the Aquila Rift", for example.
I also spotted references to other scifi authors. There's one episode from the first season that is almost 100% something Bradbury would have written (without me telling you which one, can you guess which episode I'm thinking of? Just to doublecheck my own perception), and of course "Pop Squad" from the second season is based on the short story of the same title by Paolo Bacigalupi (from "Pump Six and Other Stories").
And I'm sure I'm missing many more!
4 years ago by herbstein
I saw some of the same things you'd have seen in the MoMA (not actually called that) in Nice, France. Walking into the room of these insanely blue paintings and sculptures was almost a religious experience. It's the first time I experienced Stendhal Syndrome[0]. I just had to stand there and stare for a while.
Yves Klein's "Leap into the Void"[1] is another one of his works that really grabbed me when I first saw it. Can't quite explain it. Those are the best types of art experiences in my book.
4 years ago by abeppu
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.
4 years ago by skunkworker
This happens every wintertime for me as blue string lights are put up, and they always appear āfuzzyā compared to other colors.
4 years ago by nyanpasu64
Technology Connections did some videos on "Making Holiday Lights Less Garish", where instead of using narrowband colored LEDs he filtered white ones: https://www.youtube.com/watch?v=PBFPJ3_6ZWs
4 years ago by smusamashah
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.
Now I understand why blue in particular. Damage is done, I wish I could take it back.
4 years ago by pionar
Wait, stars are flickering dots for most people?
4 years ago by jbmny
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.
4 years ago by abeppu
Do you also find that this effect is way more pronounced in recent years with LED string lights than colored lights many years ago? I think b/c LEDs are more monochromatic, I will notice a difference between my parent's extremely old string lights and newer sets.
4 years ago by soheil
Epic! Trolling or genius marketing while a bit misleading. At the same time if people can't clearly read the sign how do they know it's an optometry and that they need to go there?
4 years ago by tobr
The author is wrong, that experiment doesnāt show anything about focusing. The blue channel in RGB is simply much less bright than the green, which means it has much less contrast, which means that manipulating it in various ways has less of a noticeable effect on the image as a whole. This happens to be true for blurring it, but also adjusting the contrast, inverting it, pixelating it, offsetting it, averaging it completely, whatever manipulation you can think of.
4 years ago by phkahler
There are also fewer blue cones in the retina, so we have lower resolution in blue.
4 years ago by mdeck_
Blue LEDs and black lights show this effect very clearly. This is e.g. described much more succinctly in the top comment here: https://www.reddit.com/r/askscience/comments/3c1qsg/why_do_b...
> 2 reasons: 1) You don't have the nearly as many short wavelength detecting blue cones as you do red and green in your fovea. 2) The angle of refraction is dependent on wavelength and short wavelengths get refracted more than relatively longer ones by your eye and therefore focus in front of your retina if you are myopic (nearsighted). The black lights are throwing off a ton of very short wavelength light and when coupled with the larger pupil you have in the dark it sets your eye up for a bunch of chromatic aberration. They should look clearer if you are hyperope or overcorrected in your myopic prescription, or if you view them at a closer distance.
4 years ago by culebron21
Interesting demo, but I think the retina resolution has more effect on this.
Also note that blue neurons are also much less dense, and our eye blue channel has natively much lower resolution.
This is why in old Windows installers, blue color was used for gradient, when colors were 16 or 256 -- blue and black dots were blurred in the eyes, while the same combo of green dots was very visible.
A windows setup with blue background: https://guidebookgallery.org/pics/gui/installation/copying/w... (Don't have a green one, but one may try photoshopping this one.)
4 years ago by Someone
I would guess the deeper reason is that the sky is blue. That makes it more useful to have good vision in red and green.
If we needed good resolution everywhere, we might have had eyes optimizing for different colors, four eyes, etc.
Also, it isnāt as simple as this article describes. The human eye can vary its focal distance (https://en.wikipedia.org/wiki/Accommodation_(eye)) over a larger range than the effect of color aberration, so the eye _could_ optimize for having optimal focus for blue light or vary that over time.
(https://www.osapublishing.org/josa/abstract.cfm?uri=josa-68-... indicates humans can learn to do that in the lab)
4 years ago by throwaway8582
One theory I've heard is that hunting for fruit was probably a major driving factor in human color vision, as well as that of other primates. Good red/green vision would've helped our ancestors search for ripe fruit (usually red) by being able to easily distinguish it from foliage and unripe fruit (usually green).
4 years ago by crowbahr
What's funny is that most mammals can't distinguish between red & green.
For example: the reason why tigers have red camouflage is that their prey cannot distinguish them from the background green of the forest, combined with the fact that mammals cannot create green pigment for their fur (yet).
4 years ago by briefcomment
The second to last demonstration blows my mind. I can't help but feel like I'm being duped, the result is so sharp.
4 years ago by enriquto
i guess with red you get a similar effect. The green channel is the one that affects most the perceived intensity. If you blur the green everything becomes blurred.
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