Chromostereopsis | Hacker News Reader

Chromostereopsis

smartermarx.com

34 pointsEduard28 comments

I'd seen this article a while ago after noticing many ZX Spectrum screenshots have this attribute e.g. https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh...

Other colours also have intermediate depths when arranged on black, so I suspect a depth based 3D image converter may be possible "3D without the glasses", but never found the time to write it.

In my experience as a nearsighted person, this effect is much more pronounced while wearing glasses; less so with contacts, and almost nil without any vision correction.

With glasses, you might also experience chromatic aberration:

https://en.m.wikipedia.org/wiki/Chromatic_aberration

I definitely have chromosteropsis to some degree as long as I can remember.

However, when I got older and went from "perfect" vision to needing glasses (textbook presbyopia), the chromatic aberration of the lenses has intensified the chromosteropsis to a whole new level!

Moving my head around (changing angle of glasses, thus severity/direction of aberration) while looking at that top images in TFA is quite a trip. For those who cannot see what I see...imagine the red and blue being printed on separate sheets of transparent film, and then slid around a few mm independently.

I've had to change my terminal colors to be more pastel to nearly eliminate the effect when I'm wearing glasses. I found it to be too distracting, especially since slightly turning my head would make blue text move around!

Confirmed - same effect here.

I see blue as a fair distance back from red, and I don't wear glasses.

Somewhat related, I recently learned about plain stereopsis and why it matters for motorcycle safety.

https://youtube.com/watch?v=doSDfIo61r0&si=wNo0PKsEaUWdxd9-

There’s an annoying tendency among YouTubers to string what is usually a 10-second explanation into 5+ minute long videos with unnecessary gimmicks, putting the meat at the very end.

TL;DW on stereopsis: 0) Both eyes are required for depth perception; 1) When drivers quickly check their left and right, the extremes are covered only by a single eye; 2) With neither depth perception nor secondary clues (like distance between the headlights in case of a car), the speed of an object coming directly at you is impossible to assess.

That trend is called 'monetization' if you look at historical videos you can even tell where youtube keeps changing the minimum length for monetization.

Awesome video. Anyone who rides a motorcycle (or really any e-bike, scooter etc) ought to see this

TLDR: the combination of one-eye depth perception and a small vehicle means when cars entering a roadway check for traffic, they will see you as a rider but they won’t be able to judge your speed- and therefore they will assume you are going the normal speed/speed limit. So as a rider, don’t travel faster than that around intersections

This effect is much more apparent if you wear glasses, especially so if you’re astigmatic.

The corrective powers of the lensing accentuate this effect.

I'm a near sighted glasses wearer with astigmatism and I'm not seeing anything I wouldn't expect to (though blue/red can be quite 'jarring', but I'm not seeing the 'depth'). Apparently some people experience it, some don't, but I can't find anything about why or what that distinction really means.

Interesting, I've never worn any sort of corrective lens and experience the effect fairly strongly

oh, hey, I always noticed this effect on days I wore my glasses! I just assumed it was a chromatic aberration due to my cheap-ass lenses. But this article says it's actually more subtle and interesting.

> This non-correspondence of retinal positions during binocular viewing can elicit an experience of depth,

I don't have binocular vision but I am still seeing the blue as being deeper than the read, so I think some assumptions may need updating!

If you’re moving your head or screen at all, wouldn’t the same chromatic aberration explanation predict a parallax effect? I also see it if I close one eye, but only if I move my phone side to side a little.

Lost all vision in my right eye to retinal detachment over the summer, but to me, the brains look closer than the background in both cases, though maybe more pronounced in the red brain on the left.

I see the blue deeper than the red, but the effect goes away when I close one eye.

I learned about this phenomenon earlier today, from an artist who does a fantastic job teaching colour theory and colour science under the handle “color.nerd”

If this interests you, I highly recommend having a look: https://linktr.ee/color.nerd

This appears to be related to the https://en.m.wikipedia.org/wiki/Pulfrich_effect where darker part of the image are processed a bit slower by the brain and movement can give effect of depth. To Scott had a video on it https://m.youtube.com/watch?v=Q-v4LsbFc5c

There's also https://en.wikipedia.org/wiki/ChromaDepth which uses diffraction grating prismatic lenses to enhance this effect.

do stereograms use this as well? I recall the magic eye books https://www.google.com/search?q=magic+eye

Since eye lenses are axial symmetric the diffraction difference of colors towards ear/nose is unlikely, to be polite. Depth focusing difference sounds a better founded explanation for the phenomenon.

When you shake an image which has red figures on a blue background or vice versa, they appear to move independently as if joined by an elastic linkage.

I do, but I don't really have stereo vision (amblyopic strabismus), which makes it even stranger.

At last! I noticed this when reading power shell error messages, red text on blue. No one else seemed to see it.

That's why I beg UI designers to avoid that color combination. It's very difficult for me to read without getting eyestrain. Here's another example that you can try at full size with both eyes open:

https://twitter.com/AkiyoshiKitaoka/status/17000613533467980...

For me, the effect only seems to appear when I have both eyes open. I suppose that's not surprising:

https://en.wikipedia.org/wiki/Chromostereopsis#Binocular_nat...

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