alt.hn

4/20/2025 at 7:17:58 PM

Find the Odd Disk

 https://colors2.alessandroroussel.com/

by layer8

4/20/2025 at 9:19:11 PM

I was wondering if it got harder or if it's just random:

    function generateColors(difficulty, blacklist) {
        ...
        let sample = Math.floor(Math.min(Math.max(0, 1-Math.pow(1-difficulty, 1.5)), .99)*5);
        let distance = (5 - sample)/5;
        ...
    }
    function setupRound(blacklist) {
        ...
        const data = generateColors(currentRound/totalRounds, blacklist);
        ...
    }
Plotting that first magic: https://lucb1e.com/randomprojects/js/testformula.htm#%24%28%...

    round#  difference
     0-- 2  5
     3-- 5  4
     6-- 9  3
    10--13  2
    14--20  1
The "blacklist" parameter prevents that you get the same challenge twice. Note also that it submits every answer to the server (fine imo, but I think it would be even nicer if this was mentioned on the page)

by lucb1e

4/21/2025 at 12:29:30 AM

I appreciate https://lucb1e.com/randomprojects/js/testformula.html, it's a cool idea!

by tennysont

4/21/2025 at 1:53:25 AM

Happy to hear, though note the file is without l (lowercase L) in the end (I guess autocorrupt is to blame here?). Fun fact: if you remove the filename, it'll show you all the crap in that directory, listing this file as being last modified in 2015-09-27. If past performance is an indicator, it should be stable to use for the next ten years as well :D

by lucb1e

4/21/2025 at 9:40:45 AM

Thanks for posting, I thought the same thing... my (useless data point of one) results showed 100% accuracy except the last four, which I thought "wow, I am just guessing now, can literally not see a difference".

by readingnews

4/21/2025 at 4:25:01 AM

Got 18/20. I chalk that up to spending years as a graphic designer. I'd like to see a similar study about which text was perfectly kerned, or by how many pixels an element was off-center or misaligned. I can spot that on billboards a block away, and my life is therefore a constantly grating experience.

Marginally related. I paint oils as a hobby, and my studio gets northern light, usually overcast and cloudy, during the day. Differentiating tiny color variations under those conditions is very easy, and in general your objective "pitch perfect" impression of color is also pretty accurate. However, I've painted in the same room at night under a "warm" LED bulb, and been absolutely shocked at how wrong and blue everything turned out when seen in the light of day. Not just that, but the hues I intended to be close to one another are much farther apart than they appeared under LED lighting.

So if lighting conditions can shift not just your perception of a color, but also its relationship to the ones around it, then I think how much more does your screen gamma and range alter that? A fair test would be printed on the exact same Heidelberg in 4 colors.

by noduerme

4/21/2025 at 6:25:35 AM

Regarding the LED lights: unless you use a lamp with CRI < 90, you see obvious, glaring color distortions, and some colors just "disappear", cannot be seen, because of the lack of a particular spectrum bands. Sadly, most inexpensive LED lamps have CRI around 80, and that light feeld definitely artificial, even if pleasant to the eye. A lamp with CRI 90 is okay, most things look natural, even though you can notice it's not sunlight. A lamp with CRI 95 is very fine, it's practically sunlight, and most tricky colors are visible well. I've never encountered a lamp with CRI, say, 97, but they exist and cost a lot.

(Source: doing object photography.)

by nine_k

4/21/2025 at 10:56:17 PM

IME producing artwork that relies on subtle color relationships requires high quality, "full spectrum" illumination. Natural daylight is the obvious canonical option, but of course not always practical.

My studio gets very little natural light, so selecting optimum light sources is crucial. At one time the most practical option was D50 compliant fluorescent tubes, but these were only fairly acceptable.

Situation with LED lamps is also difficult. Even CRI 90 is inadequate, mainly poor red emission and excessive blue radiation. However D50 compliant LED fixtures are available if somewhat more expensive vs. typical LED lamps.

One vendor worth checking out is Waveform Lighting [0]. They offer several types of products with CRI 95 and CRI 99. I've been using their D50 'shop light' for several months and find it very satisfactory.

[0] https://www.waveformlighting.com

by jrapdx3

4/21/2025 at 7:36:26 AM

Surely an incandescent bulb, being a black body radiator, has a CRI of 100? Yes, the temperature is low compared to sunlight, but the rendering is theoretically perfect.

I suppose if you want to get closer to sunlight, you need a carbon arc, which is only a few hundred degrees cooler and again, a perfect black body emitter.

by madaxe_again

4/21/2025 at 4:59:02 PM

Yes. An incandescent bulb is basically the reference for CRI 100. The parent of your poster is explicitly discussing non-incandescent technologies.

by jerf

4/21/2025 at 10:31:30 AM

I got 19/20. Turned off True Tone and cranked the screen brightness. Half the time I didn’t know if it was just my eyes playing tricks on me, but it was interesting to notice how the colors seemed completely indiscernible for a few seconds and then suddenly one stood out.

by slowwriter

4/21/2025 at 5:04:48 AM

Swear on me mum I saw a game about kerning and alignment years ago on HN or proggit and of course it's impossible to find on search

by 01HNNWZ0MV43FF

4/21/2025 at 1:50:26 PM

> I'd like to see a similar study about which text was perfectly kerned, or by how many pixels an element was off-center or misaligned.

> Swear on me mum I saw a game about kerning and alignment years ago on HN

Can't Unsee - https://news.ycombinator.com/item?id=27188989 - May 2021 (126 comments)

by isp

4/21/2025 at 5:32:24 AM

I recall playing one that had to do with making sure the kerning was aligned…

by evulhotdog

4/21/2025 at 5:36:28 AM

Kern Type, perhaps? https://type.method.ac/

by pronoiac

4/21/2025 at 11:08:05 AM

This is absolutely brilliant! And an example of why every time I come up with an idea, I should check to see whether someone else had made it before. But brilliant.

I got 100/100 on the first six, except for "Yves" where I got 70/100. I think they're wrong on that one. From any distance, the v should really nestle beneath the Y.

Gonna send this to all my design nerd friends, thank you.

by noduerme

4/21/2025 at 12:06:59 PM

I also got 18/20, I was confident on most of them, blinking I found "reset" my vision and made it easier. This was on my relatively comfortable (not too bright) monitor.

by 0xTJ

4/21/2025 at 6:20:13 AM

Yeah, metamers are a trip and a bad LED bulb will really screw with the appearance of colors. If anything, screens are more consistent, but more limited.

by rcxdude

4/20/2025 at 7:39:05 PM

I wish this had a "I can't tell" option. A few of the really hard ones I got right, but I'd say it was more of a lucky guess than a genuine ability to discriminate the difference.

by zootboy

4/20/2025 at 8:00:14 PM

Quite. With the odds being 1 to 3 you'll pick the right one when you have to click one at random to proceed, the results get skewed.

by Freak_NL

4/20/2025 at 8:25:39 PM

If you repeat the test a few times, it'll average out.

by Retr0id

4/20/2025 at 9:05:18 PM

That's why there's 20 rounds I guess. If you could just press "all the same" it wouldn't have to be as many

by lucb1e

4/20/2025 at 7:43:02 PM

This is from the creator of the ScienceClic YouTube channel [0]:

“As part of the next video, which will be out in a few weeks, l'd like to invite you to take part in an experiment about color perception. If you don't experience color blindness, l'd greatly appreciate it if you could take this test. Feel free to try it as many times as you like, think about it as a game!”

[0] https://youtube.com/@scienceclicen

by layer8

4/20/2025 at 7:46:12 PM

Would be interesting to get some basic analysis of my results. From a glance it appeared that the ones I missed (6) tended towards red. The low saturation ones and green ones I found to be easiest, but was there any actual significance of the distribution of my errors? Simply too small a set to say?

by nkrisc

4/20/2025 at 8:51:20 PM

I got the same number wrong but I've passed every Ishihara test ever thrown at me. I did this test on a cheap mobile that's not calibrated, so it's anyone guess what its gamma and transfer curves are like.

One should only take such tests seriously if one's using a properly calibrated monitor and it's viewed under ideal viewing conditions.

by hilbert42

4/21/2025 at 12:07:31 AM

Interesting! All of my misses were blue leaning a bit towards violet.

by robertclaus

4/21/2025 at 6:01:52 AM

Same here. The blues/purples were all alike. Reds and greens were easier.

by kamma4434

4/20/2025 at 7:40:32 PM

17 out of 20. Was super easy until #10 and I had to stop and think more carefully (which was actually my first mistake), and then I got #14 and #15 wrong. The score was about what I expected, though - would've been surprised if it was <15 correct.

I wonder how much of this would come down to screen calibration / color accuracy? If everything's consistently off in 1 direction I guess not much, but I would imagine certain shades might appear effectively the same on some cheaper screens?

by tripdout

4/20/2025 at 7:55:11 PM

How much of the result is vision accuracy and how much is dependant of the display?

by blueflow

4/21/2025 at 9:12:21 AM

There is certainly also a device limitation. I would expect that with less than full 24 bits of color, some fields might just look the same and the results do not depend on your vision any more.

Let's say the device has a "24 bit color display". What about eye protection color shifting? This limits the color space used could reduce the effective remaining bit depth. Or maybe they do temporal dithering to get more bit depth? Or maybe the 24 bits are already achieved with temporal dithering?

It does not need to be a calibrated display, but a cheap tablet in sunlight will be worse than a color grading monitor in a reference environment.

I hope they also register the devices used and analyze the statistics on that.

by schobi

4/20/2025 at 8:57:09 PM

As I've mentioned, you can't take this seriously unless you've a properly calibrated monitor.

by hilbert42

4/21/2025 at 12:23:02 AM

Calibrating a monitor is intended to ensure that colors on your monitor closely match colors on an ideal reference monitor. That's not the same thing as ensuring that two different colors on the same monitor actually show up differently; that's a much looser quality standard, because even a badly mis-calibrated monitor may still show both colors as distinct wrong colors.

I would only expect poor calibration to break this test for colors near the edge of the display's gamut, or if there's a drastic-enough shift that the color space's lack of perceptual uniformity means a numerical difference that should have been visible ends up in a different part of the color space where that same numerical difference is not perceptible.

by wtallis

4/21/2025 at 3:20:01 AM

Well, I initially ran the test on my cheap vivo phone when I switched to my Motorola the difference was very noticeable, there's obvious color crushing/reduced visible color gamut on the vivo, they're like chalk and cheese when compared side by side.

BTW, I used to calibrate color grading equipment for the film processing industry and the controls were strict, 18% gray walls, D65 calibration sources, densitometric equipment, Ishihara tests for me, etc. so I'm well aware of the issues.

by hilbert42

4/21/2025 at 3:27:08 AM

I think you mean gamut? Calibration would only make the discs have the most correct color, not discernible colors.

by zamalek

4/20/2025 at 7:56:59 PM

What stood out a lot in this exercise is that when looking at, versus near a disc, its luminance (or maybe the color as well) is perceived as changing. Almost the same i have when staring at not too bright stars, they seem to disappear when staring directly on them.

And related, I once had an 'eye migrane'. During that half an hour, the figures of a clock disappeared the moment i looked at them.

by nuancebydefault

4/21/2025 at 2:34:42 AM

I experienced this too. IIRC the brightness-sensitive rod cells are more concentrated in your peripheral vision while your central vision has more colour-sensitive cone cells. This makes the centre of your vision less sensitive to dim objects, so you can see them only while looking indirectly (and they "disappear" when staring at them)

Another related effect is flickering of badly designed lighting only in my peripheral vision. When looking directly at the lights they look fine, but when the lights are in my peripheral vision they appear to flash distractingly. I think the peripheral vision is optimised to detect fast changes/movements. At least, that makes sense based on evolution.

by Liftyee

4/23/2025 at 4:31:27 PM

The flickering i see as well when looking near my ali express outdoor LED light strip, from the corner of my eyes. The sub-components of the PWM seem to emerge as well.

by nuancebydefault

4/20/2025 at 8:54:11 PM

I'm curious how the eye migraine is related. I had one many, many years ago. It was a smallish (palm at arm's length) oval in the center of my vision that looked like snow on an analog TV, accompanied by a feeling of overwhelmed by all the colors of the products on the shelves (I was in a grocery). It stuck around for about half an hour for me as well.

I've also had eye floaters which cause things to distort and can be hard to see through. For about 6 months I had a large one in the center of my left eye vision, which was a bit scary when I discovered I might not see a car reflected in my wing mirror.

by fallinghawks

4/20/2025 at 11:42:43 PM

I’ve had visual migraines ever since I started training hard with weights. Played sports in High School and never had one, but suddenly I’m doing CrossFit in my late 30s and an hour after a workout I get these sparkly jagged lines in my vision (both eyes!). It took a while to even be able to describe them, let alone figure out what they were. Thankfully there’s no pain and they clear up after a while, but I have noticed since this all started that I’m also a bit more sensitive to screen brightness. That HDR emoji article from the other day was kind of triggering.

by twodave

4/21/2025 at 1:28:18 AM

Sounds like symptoms of impending retinal detachment - ex discussion https://www.reddit.com/r/myopia/comments/o7rhi3/retinal_deta...

by z0r

4/21/2025 at 10:55:57 PM

I doubt it. I’ve described the issue to multiple eye doctors, none of whom mentioned this. It’s literally a psychedelic looking jagged line in my vision (which I can see with either of my eyes closed, superimposed over my vision). I’d think if it were an eye issue directly it only affect one or the other (or if both, it would be discernible which one is flaring up).

During an episode I usually first notice it as it is entering my focal region and interfering with reading. Then it sort of moves across my field of vision until it’s in my peripheral, and then goes away altogether.

by twodave

4/23/2025 at 4:37:05 PM

What i saw during the eye migraine when closing my eyes was jittery jagged short bright lines, together forming a half moon. When i looked that up on the internet back then, it was explained as symptoms of 'eye migraine' and i believe it is an inflammation of the visual nerve. The disappearing numbers on the clock were quite scary, that is why i remember.

by nuancebydefault

4/21/2025 at 4:50:24 AM

The characteristic ‘jagged lines’ of aura is not at all related to the characteristic visual flashes of retinal detachment which an entirely different pathophysiology. Given that the advent of the flashes are new and related to exertion however it wouldn’t be unreasonable for the OP to keep a log of onset and duration and consider neurologist referral if they were to become more common with consideration for screening imaging as there are certain conditions related to exertion that can trigger aura

by robbiep

4/21/2025 at 2:18:54 AM

I had visual migraines for years, and was thankful they weren't full-blown... until I started getting headaches that lasted 18+ hours (pretty sure they're migraines). Now I'm just thankful I don't have multi-day-long ones.

by gblargg

4/21/2025 at 7:15:59 AM

The symptoms you mention read like scintillating scotoma: https://en.m.wikipedia.org/wiki/Scintillating_scotoma

I've had it happen many times and it's usually followed by a regular headache. Quite terrifying the first few times it happened to me. Felt like I was losing my sight.

Spending the whole night gaming when I was younger would sometimes trigger it in the morning. Thanks to not having any more time for that, it hasn't happened in years.

by alternatex

4/23/2025 at 4:40:20 PM

Indeed the animated jitter in the meadow shown on Wikipedia is close to what i remember seeing. 'Cortical spreading depression' is said to be the cause.

by nuancebydefault

4/20/2025 at 9:00:48 PM

Similar experience. What surprised me: sometimes the odd-one-out was really quick/easy to see, and other times it took much longer & I thought "at the end, they'll say all disks were the same color".

Got 14/20

by RetroTechie

4/21/2025 at 6:28:25 PM

For some of the easier ones, I was surprised by how aggressively my brain was making what seemed like "close" colors stand out. Like it was mentally "highlighting" the odd one out. I thought that was cool, but eventually the later ones were hard enough that the effect went away, and I was much less confident in my choices, and I got 3 mistakes, all in the last five rounds.

The way your brain manipulates your vision 24/7, with no way to get around that, is truly crazy to me. There's all sorts of effects in your visual system like edge detection and certain types of stimulus suppression that it's crazy we even feel like reality is coherent.

by mrguyorama

4/20/2025 at 8:05:06 PM

19/20. The first many were very obvious. I missed #14 and I think right around there I started to slow down because the differences were getting smaller. Looking away and then coming back helped, I think. It seemed like if you look at them too long, whichever circle you're looking at seems to shift color and it becomes really hard to discern the difference.

by fallinghawks

4/21/2025 at 5:21:47 AM

Interesting. Got 19/20 too, and also missed #14!

by archmaster

4/21/2025 at 7:11:55 AM

The X-Rite Color Challenge and Hue Test:

Are you among the 1 in 255 women and 1 in 12 men who have some form of color vision deficiency? If you work in a field where color is important, or you’re just curious about your color IQ, take our online challenge to find out. Based on the Farnsworth Munsell 100 Hue Test, this online challenge is a fun, quick way to better understand your color vision acuity.

https://www.xrite.com/hue-test

(My memory is that the full test used to be online.)

by js2

4/21/2025 at 6:18:38 PM

What is "color IQ"? Color identification quotient?

by red75prime

4/21/2025 at 12:16:16 AM

19/20 - <https://i.imgur.com/GplfQbO.png>

By the way, I keep Night Shift enabled all the time: <https://i.imgur.com/LGkSlJZ.png>. I don't know how much it matters in a game like this.

See also <https://susam.net/myrgb.html> for a colour guessing game I wrote last year.

by susam

4/21/2025 at 2:23:05 PM

> I don't know how much it matters in a game like this.

Probably significantly since it explicitly tells you to disable any blue light filters on your screen.

I think the website needs to be more explicit that this is trying to gather data and that deviating from the test parameters will skew the results.

by richrichardsson

4/20/2025 at 9:47:21 PM

Shouldn't there also be a few "control" challenges sprinkled in where all three are the same color and there's no "right" answer? If the test is implemented well and/or there is no human bias (either from the previous question or from the positioning of the circles), then you'd expect to see a uniform distribution of answers on the control. If there is bias (e.g. some innate preference for the top circle (say)), that should get adjusted for in the final analysis.

by havan_agrawal

4/21/2025 at 12:31:39 AM

Toward the end, I think the confounding effect of the afterimages of the discs was bigger than the difference between the discs. (That is, when looking at the three discs in turn, the effect of the afterimage of disc 1 on judging disc 2, etc.)

by wrs

4/21/2025 at 1:17:50 AM

I noticed this too. I did much better covering up two of the disks and looking at them one at a time, or comparing pairs of disks.

by aimor

4/21/2025 at 2:16:19 AM

It could rearrange the discs each time to avoid this issue, perhaps just flipping the pattern vertically each time.

by gblargg

4/20/2025 at 8:12:43 PM

Interesting. I only got 15/20, and previously considered myself "above average" at colour distinction tests but based on other replies that's not an especially good score. I'll try again, going more carefully.

by Retr0id

4/20/2025 at 8:16:46 PM

Ah, yes, 19/20 the second time (only the last one wrong).

The first time I kept my eyes fixed in the same place roughly in the middle which clearly wasn't a good idea. On the second attempt I glanced between each circle in turn, trying to discern the difference over two points in time rather than two points in space.

by Retr0id

4/21/2025 at 12:55:13 AM

I have poor color discrimination, but excellent flicker detection (?). This last skill was discovered by the senior devs when I was doing GPU driver debug, and “we” were looking for an extremely transient high-refresh rate tile clear issue. The issue only occurred at 120Hz (or higher) refresh rate with solid clear color on a large screen, with nearly identical colors. About one 4x8 pixel tile every minute or so. That was a boring few days, let me tell you.

by thechao

4/21/2025 at 12:30:48 AM

This seems to be a test of the color accuracy of a display. I got 17/20 and the 3 I got wrong were the last 3. I did this on my iPad Pro. For the last ones, they all looked the same to me.

by ryao

4/21/2025 at 2:17:36 AM

I wondered whether any display issues caused some to have no difference. I wonder whether it could somehow do a test to be sure your display is up to the task. It's annoying not knowing whether it's a visual limitation or hardware issue that causes wrong ones.

by gblargg

4/21/2025 at 12:35:37 PM

I just tried this on my desktop's monitor, which unlike my iPad Pro that was factory calibrated, has never been calibrated as far as I know. By round 11, the colors were nearly imperceptible, although I managed to answer 4 more correctly for a total of 14/20. Those additional 4 were likely more the result of luck than actual perception.

by ryao

4/20/2025 at 8:09:50 PM

Was way easier after deactivating the Android night light.

by Animux

4/21/2025 at 8:25:58 AM

Towards the end the disk I was looking at would change color and become brighter than the others. I didn't notice until I focused on each one at a time and the "different" one became the one I was looking at.

by throwaway0665

4/21/2025 at 4:59:02 PM

Got 18/20, which I credit mostly to my calibrated display and photographer's eye for color. That said, both of the ones I missed were blue and I am wearing glasses that have some blue light filtering, which likely negatively impacted my perception of the blue parts of the color spectrum. It's food for thought as to whether or not I can effectively do post-processing of my photos while wearing glasses like these.

Interesting idea though. I wonder what the distribution looks like?

by tristor

4/20/2025 at 8:55:48 PM

13 out of 20 for me. Would've been 14 but I misclicked on one early on.

by yellowapple

4/21/2025 at 2:30:55 PM

17/20, not too bad. My failures were a blue, purple and brown example.

As others have said, a lot of this also comes down to what monitor and OS you're using, glossy/matte screen type, interior lighting and how everything is configured. This will be a lot easier with an OLED and all but impossible with an old TN panel. And whether HDR is enabled or sRGB mode, etc.

by Night_Thastus

4/21/2025 at 5:34:47 PM

I'm not sure there is strong signal about individual performance or human perception in the noise of variation between displays, display settings, and, angle of view.

I have two monitors stacked vertically and this loaded on the top one and I'm fairly sure the latter was as big a factor as actual difference for the least-varying challenges.

by aaroninsf

4/20/2025 at 8:21:23 PM

7/20. I'm also red green colorblind so that likely has something to do with it. Could also be the phone screen I'm looking at.

by MisterTea

4/20/2025 at 9:18:38 PM

With phone screen on full brightness I was able to get 14/20.

by MisterTea

4/21/2025 at 1:46:38 AM

Not bad, I only missed 2 on purple and 2 on brown. It seems those laser safety and solar eclipse goggles do indeed work!

by 1970-01-01

4/21/2025 at 7:34:06 AM

Definitely not a brag, but I scored 20/20 on my first attempt. Is this because my phone has a particularly good screen that renders colours very accurately?

I’m not in any way involved with art or graphic design or have any experience working with anything to do with colours so I can’t chalk it up to experience.

by danw1979

4/21/2025 at 2:15:34 PM

Hmm M3 macbook pro screen, brightness at max.

At about 13/20 they all started to look the same. I even turned off truetone at like 16.

I ended up scoring 15/20, but it's more like 12/20 and 3 lucky guesses.

But then I'm well known to not know or care about subtle colour differences.

by nottorp

4/20/2025 at 8:48:53 PM

I think it matters what colors you looked at in the previous screen. It takes a while for the eyes to adjust.

by amelius

4/20/2025 at 8:27:56 PM

17/20

Wonder how big an influence the type and quality of screen has. Do OLEDS give an advantage for instance?

by _Algernon_

4/20/2025 at 7:39:25 PM

18/20 correct, I think I did well? Interesting how sometimes it's more of a feeling than an objective perception.

At the end it says I can play again, because it'll generate more data. But for what?

It'd be cool to see some stats, or learn a bit more about what I just did...

by isoprophlex

4/21/2025 at 6:56:07 AM

18/20 :D The only two I couldn't really discern were indeed the ones that I got wrong.

I'd be curious to see some sort of score for each in terms of similarity in terms of human perception, just to get a scale of difficulty.

by junon

4/21/2025 at 2:27:44 AM

Is it sleep deprivation or do the disks actively change colour and swap places?

I think this must be a low light optical illusion - something to do with different sensitivity in center of eyes vs peripheral. Will try again in the daytime.

by Liftyee

4/21/2025 at 3:21:49 AM

I definitely noticed that effect (it's late here as well) - I found it necessary for the last couple to look at the center of the triangle rather than each dot in turn.

by daemonologist

4/21/2025 at 2:25:24 PM

18/20. I struggled most with the blue ones, but it was actually a purple and a green one that I got wrong - which wasn't what I was expecting! ASUS sRGB OLED at 50% brightness.

by matja

4/21/2025 at 3:44:29 PM

17/20 for me on Windows 10 with a cheap(ish) 27" 1440p gaming monitor. I really struggled with the purples so I'm wondering if that is more the monitor than my eyeballs.

by alyandon

4/20/2025 at 8:21:37 PM

17 out of 20. good enough for me. actually, i wonder how many of the 17 were just lucky guesses haha! they mention data in the end screen, i wonder if it will be made public (so i can see where in the bell curve i sit)

by ilker2495

4/20/2025 at 9:46:10 PM

Not sure what to make of this. Most looked the same and I couldn't tell if I was really seeing a difference or not. 12/20. (And I am color blind, so not sure if that has a lot to do with it or not.)

by morning-coffee

4/21/2025 at 12:13:10 AM

20/20 but I've always done well on these color tests. I had to pause for a second and look with my head twisted though so the afterimage of the previous color didn't affect the next one.

by colordrops

4/20/2025 at 8:44:19 PM

My 14/20 went up to 18/20 after I turned up my phone brightness.

by rkagerer

4/20/2025 at 7:37:39 PM

I think this would be more fun if it started out easier, but most importantly if it gave you some real world stats at the end, such as how you compare to others, or whether you're colorblind etc.

by OisinMoran

4/20/2025 at 8:02:10 PM

I found it did start out really easy, getting harder half way. You might have some form of colour blindness (or a really bad monitor).

by Freak_NL

4/20/2025 at 10:08:55 PM

14/20. Increased brightness to full, turned off blue light filter (aka night light on Android), zoomed in, scrolled the circles up and down to dissipate after image from eyes, 19/20.

by smusamashah

4/20/2025 at 8:18:45 PM

Black text on dark grey background, sorry, that's too hard to read.

by two_handfuls

4/21/2025 at 1:14:26 AM

It's true that white text would be more readable on that background: https://www.achecks.org/apca-accessible-colour-contrast-chec...

The dark-mode browser extension I use changes the text from black to white on that page, which I hadn't noticed wasn't the original text color until you pointed out the poor readability of the black text.

by layer8

4/21/2025 at 12:33:56 AM

Your display might have a more serious gamma problem, because the contrast ratio there isn't horrible on the displays I've tried. Or maybe your display is just set too dim for your viewing conditions. The test probably does legitimately need the neutral grey background.

by wtallis

4/21/2025 at 11:06:45 AM

14 and 15 when doing it relatively quickly. 20/20 when i looked away from the screen for circa 5-10 seconds after each difficult set from 10th one onwards.

by kuratkull

4/21/2025 at 12:23:48 AM

20/20 (once) - I found that by looking at the edge between the border and color sample that I could usually tell pretty quickly.

by terr-dav

4/20/2025 at 8:43:27 PM

19/20 the neon blue one really messed with my head and kind of hurt to look at for some reason, so I am not surprised I got it wrong.

by vinnymac

4/21/2025 at 4:06:49 PM

13/20. Didn't analyze the results, but I immediately tried it on my other monitor and got 19/20.

by kimbernator

4/21/2025 at 2:05:39 AM

Aww. 16/20. Seems like this is the worst score anyone's posted, other than the color-blind guy who tied me.

by the__alchemist

4/20/2025 at 11:23:02 PM

I got 16/20 but I am colorblind and tried it on a small 8+ year old laptop screen in dubious lighting conditions :)

by dark-star

4/21/2025 at 5:15:19 PM

Apparently I have trouble telling the difference between different shades of pink...

by Teknoman117

4/20/2025 at 9:17:57 PM

Tried it briefly, upto 6. Got all right. Gonna do more later.

Need some interesting optical illusion type of posts on HN!

by fuzztester

4/20/2025 at 8:21:42 PM

19/20 somehow on my first try. Near the end was just tiny differences in saturation or brightness.

by jjmarr

4/20/2025 at 10:23:01 PM

I got 17/20, but then again I have a high-end NEC PA302W hardware color-calibrated monitor.

by fmajid

4/20/2025 at 11:09:57 PM

18/20 on an uncalibrated "gamer" spec display with windows' late night colour yellowing turned on. I'd argue spec/calibration isn't maybe that important, as long as a difference can be spotted.

by Cthulhu_

4/20/2025 at 10:40:19 PM

18/20 on an iPhone – they’ve have Display P3 wide colour for many years.

by tkcranny

4/21/2025 at 12:34:37 PM

16/20 speedrun, all my mistakes were within the final 5 weirdly. Boredom?

by nand_gate

4/21/2025 at 4:18:15 AM

19/20. I'm on a MacBook, so I have a pretty good screen.

by coolcoder613

4/20/2025 at 9:17:21 PM

Browser > right click on the dot > inspect the RGB numbers

by theoa

4/20/2025 at 9:57:47 PM

The first line on the page says

> Click the disk that's a different color. Use your eyes only!

Inspecting the color is cheating.

by Mogzol

4/20/2025 at 9:18:26 PM

Clever.

by fuzztester

4/21/2025 at 3:43:16 AM

does 20/20 on my first try mean i get the job?

by akww

4/20/2025 at 9:07:24 PM

How do I know my screen can display all of these correctly? I tried on three different screens, one of which I know is bad, and got 16, 16, 18. Is those two mistakes the error margin of the screen if my eyes are fine, or much more likely to be the error margin of my eyes?

For those reporting scores: please also report device type, like LCD/OLED, or which phone model if applicable. Tweakers.net has a large database of screen color measurements. As mentioned in e.g. https://news.ycombinator.com/item?id=43746400, it can make quite a difference

My 18 score was on an Oppo Reno8, the 16 score on the not-known-bad screen is some ~2008 display. On the former, Tweakers reports an average color error of 3.42 ΔE2000, 9.58 ΔEITP, or 2.60 ΔE2000 if white is excluded

by lucb1e

4/21/2025 at 8:42:25 AM

Your score: 17 out of 20. Mistakes: 3

by bobbyblackstone

4/21/2025 at 2:41:38 AM

Oh god this is colorblindness torture

by saagarjha

4/20/2025 at 8:13:27 PM

Your score: 20 out of 20. Mistakes: 0

by dvh

4/21/2025 at 7:50:36 AM

I honestly felt the grime on my phone’s screen had more impact on my accuracy than anything else. Sometimes i’d just rotate my phone and instantly spot the difference after the disks moved.

by laserbeam

4/21/2025 at 1:13:35 PM

Interesting, it'd be neat if it showed the one you missed.. I had 19 of 20 correct, but I don't know which one I got wrong.. and my wife tells me I'm terrible with colors because I insist most turquoise are greener than they're blue :P

by dusted

4/21/2025 at 2:37:28 AM

11 of 20.

by SoftTalker

4/20/2025 at 11:37:04 PM

[dead]

by nsibr

4/21/2025 at 7:19:23 AM

[dead]

by shriramhack