Color blindness | Hacker News Reader

Color blindness

commandcenter.blogspot.com

321 pointsbumbledraven161 comments

I'm r/g colorblind, and suddenly the indistinguishability of small colored objects makes sense now.

Wow. Okay then.

I hate multicolor LEDs with a passion. Those little amber or green dots look identical to me, even when you put them side by side. I use a phone app that uses the camera and shows me RGB values at a reticule. I've gone through rack and racks of equipment with that app, looking for things like dead drives and errored-out ports. Back in the 80s, I borrowed the eyes of cow-orkers (with the cow-orker still attached).

My wife was a PM on a project once, and asked what I thought of a bit of UI. The designers had replaced a set of small status icons with colored dots (green=ok, red=bad, puce=alerting, etc.). I explained that I could not distinguish them. They didn't believe me; it took that team about five months to come up with a UI that made sense (the same icons, but with colored, duh).

> I use a phone app that uses the camera and shows me RGB values at a reticule.

Could you share the app name? It would make my life a bit easier (I hate those red/amber/green leds that look identical) :)

On iOS, it's "Color Blind Pal".

On Android, there's "Color Blind Pal" that I use, doesn't use RGB values, but gives you names for the colors instead.

I’ve been happy using Cone on iOS after seeing it get brought up on HN previously. It’s paid, but it was worth it to me.

I use Color Blind Pal on Android. Been using it for a few years.

If you get it, I'd recommend going into the settings and increasing the sample size - it defaults to "small", which given the way it flickers I'd guess means "1 pixel" :) I use it on the "large" setting, and it works great.

Oh thank you, thank you.

I just installed that and do not know why I never tried to find something like this.

I am not sure how setting the kind of color blindness helps but having the color names displayed is wonderful.

I was flashing a router which seemed broken. Each flashing was failing.

Then my brother came by and asked me if I was trying to trigger a failed flash?

WTF?

As you now guessed I was seeing these little motherfucker LEDs as red when they were green.

I hate them with passion. And I work in IT, they are everywhere.

I sent a few days ago a picture of my home fibre converter to my wife when she was out with friends so that she tells me what colors are the tiny LEDs when Internet was down. This is a nightmare.

Do you reckon AR glasses fix this issue?

Not sure why you're getting downvoted.

This was my first thought. The posts above mention using an app to read RGB. An overlay using AR would bring immediate value, I would think.

My colorblindness is mild. Can tell most colors but fail the petri dish color test around round 3-4, nothing pops out at me.

It seems to me the simplest thing would be to have an app that renders the camera's reds as blue or something

It would at least suffice for these obvious kinds of things

I think the point is devices should be designed to be usable by colourblind people, without having to buy an additional device.

Can you imagine telling someone a wheelchair, that should just buy a portable crane to get into buildings that uses stairs?

That would be great, but reality is that product development at many places depends on a few people to be aware of accessibility in the design process.

And there are situations outside of product usability it will be helpful to know what is commonly seen. For example, when someone asks you to pick up X item at a store that is a color that you have a hard time identifying.

Really we should just make colorblindness part of the ADA and then companies have to solve that liability appropriately.

Ideally, colorblind people wouldn't have to deal with solely color LEDs as a signal in the first place.

I'd like to not spend money on assistive devices if I don't have to.

We live in a world where being an exception means a disadvantage. Changing some factors is difficult. For example, green means good and red means bad. That is not going to change.

My partner is left handed and she has to constantly adapt to a right handed world. Sure, you can buy products catered to both. If you buy for left hand then I can't use as right handed person. The sum is left handed people live, on average, shorter and are due to their giftedness better versed in right hand than right handed people are with left hand.

We both have autism, in an ideal world we never have to adapt, but that ideal world is simply unrealistic.

Now, my question is can AR solve this? I didn't include that I believe AR devices, including glasses, can become a norm ie. this would not be the sole reason you would use AR for.

Adaptation is unrealistic in cases where adaptation costs a lot of money or creates other maladaptations. The world's adaptation that needs to be done for colorblindness is simply not making color the only differentiator between states. And if you have to do so, using one of the many free, publicly available sources to choose a palette that is colorblind-friendly.

For example, in a traffic light, both color and position are status differentiators; the top light is stop and the bottom light is go. Many buttons are both colored and have symbols/shapes on them associated with the color. Even using entirely different senses are helpful; crosswalk signals near me use color, position, shape, and audio, the last because blind people can't see color or shape.

Color in general is just not a great sole associator, even for fully sighted people, because perception of color can change depending on environmental conditions, and because meaning of color is not standard across cultures.

There are normal glasses to fix it. I tried once and it seemed plausible, though I wanted contact lenses, and that wasn't an option back then. So there are 3 different photoreceptor cells in your retina, each responsible for one of RGB. Many "colorblind" people actually have just a lower numbers in one of the receptors and the more present receptors distort colors, like if you try to mix a color from RGB paint but don't have enough from one of the ingredients. These glasses correct the distortion. Though they can not change color perception for people whose deficiency is caused by a complete absence of one of the photoreceptors.

As a kid, before I even knew I was colorblind, I remember experiencing this with my Nintendo DS’ battery LED indicator. I believe it would show green-yellow-red, but I could never tell the difference just looking at normally. I would instead bring it right up to my eye, thereby filling up my entire field of view and I could suddenly tell what color it was.

This article finally gave me insight as to why.

Are you sure it ever turned yellow? I can’t recall it ever doing so. Then again, maybe I am more colorblind than I thought I was…

I'm not colourblind enough to be "legally" colourblind (that is to say I don't have an accurate diagnosis) but I still feel your pain. I particularly hate status indicators that are orange/green, rather than red/green, because I just cannot tell them apart at all, where as at least the red gets a bit darker so that I can tell that "dim is off", for example. Nintendo seem to be pretty bad for this, at least with the Wii, because the LED is forever this weird yellow that looks like what I'd call yellow, but actually isn't, and I had to actually switch to the input on the TV just to check if it was switched off or if I'd managed to catch the button while dusting under the TV.

There are varying types of colour blindness. For example, there are the "opia" and the "omaly" types. For r/g and y/b these seem to have different ramifications.

Mostly the "omaly" types can get by without too much fuss since colour differentiation is more muted and the "opia" types affect more of the spectrum and more difficulty differentiating if they can at all.

It's more nuanced than that, but generally speaking it tends to work out that way.

I'm also Red-green colourblind, and also use a mobile app to check RGB values of things! I also use a Windows traybar app that I wrote with Delphi about 15 years ago, which gives me a dropper I can use anywhere in the screen to see RGB values.

I've also noticed that it's much more difficult to differentiate tones and colours of small objects.

Cues were mentioned in the article, and I think I subconsciously rely on these a lot. For example, with traffic lights I know what the colours should be from top to bottom, and so I "see" them as the right colours - yet if you took photos showing only the colours in the abstract, I couldn't tell any difference between red and amber, and indeed I wouldn't be able to accurately tell you what colour any of them was.

Something people find interesting is that I often don't know what colour something is, but I'm often able to narrow it down to 2 or 3 choices - usually based on context and other cues, and also based on how I know I can misperceive colours. For example, I know I often see pink as grey, so if you showed me something pink, I might think it was "pink, or grey or green".

Another random anecdote that demonstrates the use of cues: years ago we had an old CRT TV, and every now and then it would suddenly display only in black and white. It really annoyed my wife, but I never even noticed - I guess in my head I "saw" someone's coat as red, for example. My mind just kind of filled in the blanks, like I suppose it must always do.

May I ask what apps are both of you using?

I have the same issue, and use "Color Swatch" on iOS for this.

Thank you both!

There’s an iOS app called “Color Blind Pal” which does many things, but most usefully tells you the name of the colour under a cross hair overlaid on the camera, which I find helpful as I struggle to name colours e.g. bright green vs yellow, or blue vs purple

I use "Color Grab" on Android

You need to pass a color-blindness test to get a driving license in my home country and I can't tell you how much I struggled with it 15 years ago. The reason is exactly this -- I can work out traffic lights very easily although I'm r/g colorblind, however the test was about showing a number of different colors and asking you to name them. I failed, obviously, but the instructor did a favor and marked me as passed.

I still have no idea what practicality that test provides in driving.

Wow, that's seemed unnecessarily discriminatory!

As a kid I always wanted to be a pilot, but to get a license you can't be colour-blind. I guess because light colours on runways and such confer meaning, or something like that.

I had no idea there were countries demanding this for a driving test though - I mean, it's not like they randomise the order of traffic lights!

-At a former employer, I volunteered - as in, bullied my way into - the test group for our SCADA GUI front-ends.

This resulted in palettes for both deuteranopes and tritanopes; our support staff on occasion had calls from customers who had inadvertently activated one of the color schemes for the chromatographically challenged - they typically went along the lines of 'Did you nincompoops have some colorblind sod do your GUIs?'

-'Matter of fact, we did. Would you like me to put you through to him?'

To me this is interesting that green and red look the same with RG blindness. I'm YB blind in one eye, but I can easily tell a yellow thing isn't blue, and vice versa. It's the colours around blue and around yellow that I can't differentiate with that eye. (ie: red and orange are just red, green and blue are cyan, and dark blue or purple might as well be black. Royal purple looks like rich chocolate, so that's kinda entertaining.) So the deficient pigments seem to have very different results to colour perception.

Fun fact: I sometimes entertain myself by A/B testing between both eyes with my hand. It's especially interesting at Christmas when bright colours abound. Anyone who's ever seen me doing that probably thinks I'm a bit off, but that's okay. It will probably help with social distancing this year.

That's a big reason for the order of lights in traffic lights.

New lights, around here, are also getting reflective frames, so that people can better understand the position of the active light.

https://pxhere.com/en/photo/265717

It's briefly confusing if you have only lived in places with vertical traffic lights, and then move to someplace that has horizontal traffic lights, and vice versa.

In Michigan traffic lights are painted yellow, which works well for me at night. In California traffic lights are painted black, which means at night I cannot distinguish red and yellow lights. Although some traffic lights are now getting a reflective strip around the outside, which is the best.

R/G colorblind here. I didn't realize how much I relied on traffic light order until I visited Houston, TX where the lights were horizontal. It was a very alarming experience.

I read the article and it really hit the nail on the head, speaking as someone that is also r/g colorblind.

I recently bought an Amazon Basics charger for my rechargeable AA and AAA batteries. My old one had a bicolor LED for charging and charged. The new one shows red for charging and turns off for charged. I love not having to ask my wife when the batteries are charged anymore.

Now I just live in fear of colored graphs and charts where the legend has tiny small colored squares so you can distinguish which line is which.

You wrote co-worker cow-orker TWICE!

http://catb.org/esr/jargon/html/C/cow-orker.html

Wait. Didn't cow-orkers see in black and white?

To the opposite, I have a rather good sense of color. It bothers me when designers make every icon the same color, because I distinguish colors much faster than shapes. (Much easier still than using an app that would tell me which shape it is, of course.)

I think the visual design should embrace both shapes and colors, and use color palettes that are discernible for people with different senses of color.

The objection is usually that the design must look "neat". I'd say that a visually neat but unusable design wastes all the effort that went to making it neat anyway. Being bold and even flamboyant in order to be highly visually discernible pays off most of the time; look at flowers.

Just to clarify (for my own edification) If you look at the colors #FF0000 (red) and #00FF00 (green) does one look greyish or do they both look like the same color?

Also, apparently this is news to many r/g color-challenged people: peanut butter doesn't look green to every one else. It looks brown (which I don't know if a separate color to you)

Not the OP, but I'm also R/G color blind and I don't believe I'd have any issues with those extreme versions of R and G. My issues happen with lighter shades.

For instance, 00AA00 and 00BB00 are very hard for me. 00CC00 is about when I start feeling confident I could recognize it as green, but it's be harder if the surface area was fairly small (for example text). On the red side, the recognition issues also extend to about CC0000.

I am red/green colorblind. I actually knew about this because they tested for it the first time I got glasses, and it came up there. But for years afterward I never really thought about it; I’d be able to tell basically every color and only falter on some that seemed ambiguous to me but others had an easier time distinguishing–but I never ascribed this to colorblindness; I just thought it was I who didn’t know the colors well enough. For both of your examples: pure red and pure green are very clearly, obviously distinct colors. I don’t think peanut butter looks green at all, it’s clearly a shade of light brown. Really, the only way I can describe the difference I see is this page: https://en.wikipedia.org/wiki/Color_blindness#Signs_and_symp.... There’s a picture of a landscape with various colorblindness filters applied to it. The first two images look identical to me.

I can tell you that it's not about knowing my colors, the colors of the apples you linked look as different as white vs black to me. And they would look just as distinct even if I didn't know my colors.

Yep, I would never confuse those two. And I can tell that the images on the “bottom” are somewhat different.

It seems that there are many shades (Pardon the pun) of colour blindness.

I'm R/G colour blind, but I can still see red and green. I have issues when red and green are close to one another or blended though.

It becomes impossible for me to distinguish between what is red and what is green, or where the colours start and end.

I, too, am r/g colourblind, and don't know anyone else who is. Multicolour LEDs have always been a problem for me, and my gf can't believe that I can't read them... I also have issues with the UI of one of the apps I use regularly (wavelab) as the master section on/off is the wrong shades of red and green, so that's a problem.

Thanks to everyone for posting in here about it - I no longer (at 49!) feel like I'm the only one in the world who has this issue with LEDs in particular.

This article was a fascinating and informative read for me.

The author (who I assume is male, I don't remember if he said so outright) kept repeating how colour is perceived based on the difference between receptor signals. I had learned that already so I kept thinking, "yeah yeah, I know"...

... Then he got to the point about edge detection, and suddenly I understood! I never thought before about how the difference is calculated between receptors that are not precisely co-located on the retina. Of course! Seems obvious in retrospect but I never thought about it. That also makes many colour-optical illusions make more sense.

If the author comes across these comments -- I have full colour vision and unusually good eyesight. Even for me, without magnification the stars are not colourful. Mars is slightly red, Betelgeuse is very slightly red, the milky way has a slightly bluish tinge, but for the most part, the stars are just white points. They do sometimes shimmer / twinkle briefly between different colours in a way that can make it really hard to say what exact colour they are, even if I stare at them. You probably notice that too, though. So I don't think your experience of the stars is likely to be that different, and you shouldn't feel sad!

The author is Rob Pike; https://en.m.wikipedia.org/wiki/Rob_Pike

Non-mobile link: https://en.wikipedia.org/wiki/Rob_Pike

I'm red-green colorblind but the only way it noticeably affects my life these days is with the icons on Github's notifications page. A merged PR an an open PR have different shapes and the merged PR is blue and the open PR is green --- very easy to distinguish.

But an open PR and a closed PR have identical shapes and are only distinguished by the open PR being green and the closed PR being red. Or so I'm told anyway, because I cannot for the life of me distinguish between the two. I end up needing to just open the link to the PR to check its status.

The closed PR icon has a tiny little tickmark in the icon I believe.

I had never realized they had different colors btw, and always wondered why GitHub wouldn't give them different colors. Thanks for clarifying that they actually did, just badly.

Tip for anyone using red and green for statuses: do like traffic lights: make the green a whiteish, blueish green and make the red tend a bit towards orange. And for the love of god use wildly different icon shapes!

Made an issue based on your comment. Is this accurate? http://github.com/github/view_component/issues/495

I didn't know you could do that! Thanks!

Not colorblind (my father was) but I appreciated his brief “old eyes” discussion at the end. I’m 42 and have been using a computer since I was 6. Now I’m both nearsighted (since I was 8) and farsighted (since my late 30s), which means I can’t read without glasses of some kind. Similarly, “light mode” is far easier to use and more legible than “dark mode” despite the recent trendiness of the latter. I can also back up his exhortation to not use the thinnest possible lines for text.

4K monitors have been a blessing, not directly (though they sure are nice) but because they’ve brought good fonts and UI scaling into the general use case.

The research I'm aware of has shown that light backgrounds help people with astigmatism because they cause constriction of the pupils to adapt to the increased light coming in given low ambient light, which brings things into sharper focus for those with astigmatism.

Of course not constricting the pupils is a major reason people like dark mode, and mobile devices have greatly increased the use of screens in environments with low ambient light. I suspect the only good solution is to support both light and dark modes universally.

I've got mild red-green colorblindness (less severe than the author's); this article is great, and goes into much more detail than I knew beforehand. If I could add some suggestions to the author's at the end:

* First, if you have the option of using one or the other, do so. Like, you can use red, blue, yellow, purple, and black for lines on a graph before you even need to find an additional color like green.

* Second, highly saturated ("computer" red/green) are easy to distinguish (for me, anyway, and it sounds like the author as well). So they're preferable to less saturated versions of red and green, if you need to use both.

For me, the most difficult reds and greens to distinguish are in the pastel range.

* Additionally, if you're designing UI for a program (game or whatever) with colorblindness options, PLEASE do not label the options with the medical names only ("deuteranopia", "protanopia", "tritanopia"). I don't know what the latin word for the medical condition of red-green colorblind is, I just know I have the relatively common kind of red-green colorblindness. I'd guess most people who aren't doctors are in a similar boat. Labels that include the color-distinction difficulty and relative commonality would be most useful to me, e.g., "red-green (MOST COMMON — deuteranopia)", "red-green (LESS COMMON — protanopia)", and "blue-yellow (EXTREMELY RARE — tritanopia)".

How about this for selecting. Colour scheme: just display a colourblind was test and ask the user to select the one they can or can't read. Then you don't have to rely on them knowing what the different types are at all.

Yeah, that seems pretty reasonable to me!

To add to your suggestions: avoid referring to colors on a chart by name. While it may be able to identify the difference between two colors (e.g. by intensity), it may not be possible to identify the color. In my case, identifying blue and purple are frequently difficult. Presumably this is because purple is a mixture of blue and red.

The issue isn't with referring to colors on a chart by name but with using a color name as the sole identifier. Referring to parts of a chart by color is fine, and provides additional information, as long as a line style or shape identifier is also used, e.g., the "blue solid line" and the "orange dashed line" in the case of a line plot or the "blue circles" and the "orange squares" in the case of a scatter plot. Ideally, I think color swatches should also be included when referring to colors, so it isn't necessary to match the name to the color [1].

[1] https://mpetroff.net/2019/11/figure-caption-color-indicators...

Yes, using multiple identifiers would work as well.

The use of colour swatches is interesting, though I would add that it should use a standard palette of colours to ensure that there is also differentiation based upon intensity (which would also help in the grey scale printout example).

> First, if you have the option of using one or the other, do so. Like, you can use red, blue, yellow, purple, and black for lines on a graph before you even need to find an additional color like green.

I don't see this advice getting much uptake.

First, green isn't a second thought for people with normal vision. It's a first thought. I can understand how this wouldn't be true if, to you, it didn't exist.

Second, the color space without green is harder to draw contrasts in than the color space with green.

Third, a friend of mine with red/green colorblindness always complained that he couldn't tell the difference between blue ("rare") and purple ("epic") items in World of Warcraft. (WoW has since solved this problem by throwing out the concept of item quality entirely, but the colors are still there anyway.)

So you're advising that people should make a quite unnatural choice, which will markedly reduce usability for almost everyone, but which won't actually solve the problem for the colorblind. It's just not a move that makes sense.

> Third, a friend of mine with red/green colorblindness always complained that he couldn't tell the difference between blue ("rare") and purple ("epic") items in World of Warcraft.

I call things that are apparently clearly blue “purple” a lot–I assume some sort of overcompensation of some sort. It’s strange how we adapt, isn’t it?

> It has to do with edge detection. The signals from receptors in the eye are used not only to detect color, but also to detect edges. In fact since color is detected largely by differences of spectral response from nearby receptors, the edges are important because that's where the strongest difference lies. The color of a region, especially a small one, is largely determined at the edges.

Aha! So that is why I have the hardest time with line charts even when I distinguish the colors in the legend just fine!

I didn't know he was color blind. I can't help but connect this to his famous disdain for syntax highlighting and colored text: https://groups.google.com/g/golang-nuts/c/hJHCAaiL0so/m/kG3B...

I usually ignore syntax highlighting. I can't see it well because it's tiny, and because the "designers" usually chose colors that are tough to distinguish, and sometimes very difficult to see at all.

For instance, the default console colors in Ubuntu are TERRIBLE (maybe for everyone). The output of 'ls' uses blue letters on a black background for some type of file, and I literally cannot see those. Ditto for some errors in Emacs (e.g., trying to exit w/o saving a file). That output is invisible.

If you are an engineer and decide to do something with color in your UI, please get some designer help and listen.

I wrote a small DSL editor before and I had to fight extremely hard to get a theme that made the semantic highlighting legible.

I like pretty things too, but they also need to be functional.

My vision is very good and I can confirm, the default Ubuntu terminal colors are horrible.

As a color blind engineer, I love syntax highlighting, but mostly for the "pop" and "fade" contrast effects rather than associating specific colors with semantic values.

I'm red-green colourblind (quite badly), and also use syntax highlighting for the same reasons - it highlights semantically different parts of the syntax (or not, as wanted) even though I have no idea what the colours actually are.

Anecdotal, but I have mild color-blindness and love syntax highlighting.

I do as well. At best it helps, at worst…it’s just not useful? There’s no harm to leaving it on, unless of course the color scheme is garbage and I can’t tell the text from the background.

Exactly. And some colorschemes work better for me than others, which I guess is probably true for everyone, regardless of (partial) colorblindness.

As someone who's similarly red-green colorblind, I'd say it's far more likely to be related to the amount of time he's spent reading and writing code on monochrome displays, perhaps coupled with market trends that tended to associate color with cheap/mainstream/gaming hardware vs. monochrome with expensive/professional/engineering hardware. For several reasons, there was a major trade-off between color and contrast/sharpness/resolution on most hardware until the mid-90s or so, and there was a tendency for engineering-oriented systems to embrace monochrome to get the highest contrast and resolution.

I don’t think that’s it. I used syntax highlighting for nearly 20 years then stopped a decade ago and don’t miss it at all. So I had every reason to want to use it but now I don’t even want it.

It may something to do with Plan 9. At least I stopped syntax highlighting after playing with it. It feels like unnecessary noise.

I wrote an app that aimed to simulate vision impairments, including types of colour blindness.

The idea is that the designer or developer can point their iPhone/iPad at design to get some idea of what it might be like for someone else to view it.

https://apps.apple.com/gb/app/vision-impairment-simulator/id...

>> Maybe I can help you understand how that impairment—and it is an impairment, however mild...

This is actually a slightly controversial claim. While r/g color-blind individuals do have difficulty viewing colors, they seem to have an easier time seeing through camouflage:

A study on the ability to distinguish tones of khaki:

https://www.discovermagazine.com/mind/in-combat-stick-with-t...

There is strong anecdotal evidence that color-blind men specifically recruited during the world wars to see camouflage: (I have personally heard such an anecdote).

https://www.reddit.com/r/AskHistorians/comments/a32spn/color...

And a short YouTube video on the ability of color-blind monkeys to forage for insects, whereas the monkeys with color-vision are better able to find ripe red fruit:

https://www.youtube.com/watch?v=9NrmH039ffI

I suspect that if we lived in a world where the color-blind were the majority, it would be those with color-vision who wrote about their 'impairment'. Perhaps with a note about how video games often contain almost-impossible tasks to discern camouflage. (In the real world, video games often contain tasks that require the ability to discern colors that I find difficult due to my r/g colorblindness).

Well sure. I would also assume that if we lived in a world where most people were wheelchair bound, people not in a wheelchair would be at a disadvantage.

Well, there used to be jokes about stupid women seeing non existent color differences and making big deal about them. As in women being crazy and their husbands rational having to deal with that.

Meanwhile, color blindness in overwhelmingly make issue.

You don't have to invoke color-blindness or tetrachromacy to explain that. Even normal trichromatic people will have differences of opinion about shades of blue or green. But every difference of opinion that might involve gender will always be exaggerated.

Women have a small chance to be tetrachromats, so yeah they can see colors others have trouble with.

My mom is color blind (so passes the test, but just barely), my dad very color blind. We still make those jokes.

There are some normal trichromats that also better resolve luminance and S-cone signals, so it's not necessarily mutually exclusive.

https://jov.arvojournals.org/article.aspx?articleid=2135713

Normal trichromats read Ishihara plates using their L- and M-cones. Red-green color vision defective observers rely on S-cone and luminance signals in reading the plates. Some normal trichromats can read the hidden digit plates because they can extract S-cone signal difference efficiently despite the distraction from L- and M-cones.

This is such a detailed description of the issues caused by red/green color blindness.

I've had some issues in the past specifically related to small red and green boxes. When you do some operations work you'll eventually run into a chart like this [0] and, during an outage, you'll undoubtedly not be able to notice a scattering of small red boxes in this type of visualization. Similar with line charts. Telling the difference between 2 lines on a graph that are not thick is difficult especially now that people have migrated to higher DPI displays.

[0] - http://status.ovh.com/vms/index_bhs1.html

I am colorblind. Just to be sure, there are no non-green boxes in the chart you linked to, right?

All the boxes are green, apart from the key which is bright blue, bright yellow, dark yellow, orange, red, and maroon.

Thanks, I got a bit worried :)

To be honest, if the boxes were smaller, I couldn't definitively say as I'm also red-green color blind. So I'm glad someone could clear it up for us.

One great example of the case where I absolutely cannot tell is when you have a LOT of tests in something like buildkite https://buildkite.com/features and most API status pages (many small green/yello/red circles/boxes).

> That is a worthwhile endeavor, and the people writing them mean well, but I suspect very few of them are color-blind because the advice is often poor and sometimes wrong. The most common variety of color blindness is called red-green color blindness, or deuteranopia, and it affects about 6% of human males.

This is frustrating. He's trying to correct misconceptions and then he immediately gets the word wrong. What he's describing is 'deuteranomaly'. The term 'deuteranopia' applies to the more severe form of colourblindness shown in his diagram (a); it's a form of true dichromacy.

https://en.wikipedia.org/wiki/Color_blindness#Classification

I had a woodshop/electronics shop teacher in high school with severe red/green blindness. He said at stop lights the only reason he knew which was green and which was red was because of the layout. But when he went to states with sideways lights, he'd just wait until the people behind him honked until he figured out which was red and which was green.

But as an electronics teacher, it was extra problematic, because resistors are labeled by color bands. So he would constantly quiz us on that by randomly asking us what the resistance was, because he needed to know for his own projects!

He also said a lot of warning labels on woodshop equipment was bad because they depended on being able to tell the difference between R and G.

I learned very early in life that any UI that uses red and green as a differentiator is bad.

I remember driving one night alone in a rural area with sideways stoplights. I didn't realize it until one turned red on me, until then I just saw a weird light ahead. At least red is clear to me so I would stop.

Great article. Ummm... dumb question, but... stars are colored? (Color blind poster here).

Yup.

> "The color of a star, as determined by the most intense frequency of the visible light, depends on the temperature of the star's outer layers, including its photosphere."

https://en.wikipedia.org/wiki/Star#Radiation

The poster's question should be interpreted as: can the color of the stars be distinguished with the naked eye?

Again, yes. Particularly in clusters, I can detect differences in the colors of stars.

Wow - sounds like you have more sensitive than average color perception.

Do you think you might be a tetrachromat?

Nope. It probably helps to live away from cities and such, in that there's a lot of stars visible at night. And it's not like looking at a rainbow: they're tints, not intense color differences.

'endogui linked to an article that talks about this: I don't think it's all that unusual.

https://earthsky.org/?p=2875

I am not color blind and I've never noticed star colors. They just look white or yellow to me. It must be very subtle.

It helps to be way out from the city, and some stars stand out better than others as having a color other than yellow/white.

Antares, for example, is one I can consistently see as red.

Try Mars? Not a star, duh, but it's glaringly red, even when observed in the city.

Mars is particularly bright right now too, it's quite striking.

/me takes binoculars and ventures outside... gasp!

It's just after full Moon and Mars is just next to the Moon, hence also on max luminosity.

Is it obvious to everyone else? Do colored dots stand out in the sky? Or is it a subtle thing?

To me (not colour blind), they are not really coloured. Some are slightly more yellow or blue, but that's about it.

They do, however, twinkle: https://en.wikipedia.org/wiki/Twinkling

And while twinkling, I catch glimpses of red, yellow, blue or others. Of course, this is very subjective and that wikipedia page doesn't mention colour changing at all.

It is subtle and to the naked eye, at a quick glance, the stars in the night sky are all little white dots.

Not a mass of little coloured dots.

It probaly has to do with the low visibility of stars in general. Especially mayor european cities have so much light pollution that people, myself included, just see a few white dots at the night sky varying in brightness and ever so slightly in color if you pay attention.

Also r/g colorblind, and that line surprised me. Apparently it is visible to the naked eye on the brighter stars:

https://earthsky.org/?p=2875

Stars mostly look white to me (or very light yellow or blue) and I‘m fairly confident I have standard color vision — but I’m nearsighted and have mild strabismus, so they look pretty bad unless I’m using a telescope. :(

Yes. I still see the colors of stars, but it's like a pale color. They are mostly white, but some tend toward red, others yellow, others blue. There's definitely a difference. When I see Mars, it is definitely more red, especially so when it is closer.

But I distinctly remember my young eyes, probably when I was 4, that the the stars had a lot more color than they do now. I remember talking about it with my mother while she was driving one night.

I score fairly high on color acuity tests, and gravitated toward a job in color printing in my 20s, and learned color management. I matched so many colors in CMYK and CMYKOG by hand, because the color models used to calculate color differences and tolerances do a poor job of modeling the response of the human eye to color. Since then the models have improved, but they still need work. Given what this article describes, this makes complete sense. You are mapping two very different mathematical spaces from one to the other. One based around specific pigments with specific values, and the other based around differential curves between color receptors with overlapping ranges.

Are you by any chance one of the (described in the article) tetrachromates?

Not possible. Tetrachromates have to have two X chromosomes, which means that almost all tetrachromates are women. In rare cases, a man can have two X chromosomes, but I'm definitely one of them.

Of course I meant to say "not one of them."

Somewhat unrelated story, but I used to be in astronomy and two friends of mine were once on an observing run together. Observing can sometimes be a bit dull and as you're getting night shifted it's hard to do anything productive while you're waiting for the exposures to finish. So you're looking for ways to pass the time.

Anyway, somehow my two friends started looking at color blindness tests. One of them had grown up in Latin America and hadn't seen a color blindness test before, so the other was explaining how there's a number in the center that you can't see if you're color blind. And he said... "what number?" That was how he learned at age 26 that he was color blind.

Probably not that severe.

They are almost impossible to tell apart in a lit sky.

When the sky is dark, red stars are very distinctive, I don't think even color blind people would have a problem. (I am color blind, but I confuse blue and green, not red and green.)

Both yellow and blue stars emit blueish and yellowish light, and are much harder to tell apart.

As an added bonus, red stars are the first to disappear against a lit sky :(

A color-blind poster here - this month has been the first time that I've noticed colors in stars (or planet, specifically).

Mars is very close and red these days, which I hadn't noticed before. I got quite giddy when I first saw a "colored dot" in the sky a few days ago and now most of my evening runs are motivated by getting a glimpse of the bright red planet. :)

A few weeks more until it starts rising early and isn't distinguishable anymore.

> "First, choose colors that can be easily distinguished. If possible, keep them far apart on the spectrum. If not, differentiate them some other way, such as by intensity or saturation."

Because "keep them far apart" on the spectrum might not be helpful when taken litereally, here is a link to Lines of Confusion Diagrams im CIE 1932 color space.

https://www.color-blindness.com/2007/01/23/confusion-lines-o...

> "Second, use other cues if possible. Color is complex, so if you can add another component to a line on a graph, such as a dashed versus dotted pattern, or even good labeling, that helps a lot."

I find this easier said than done. My issue with alternative cues is that they often introduce a form of unintentional order or hierarchy. For example: When I want to plot two different variables and I want to avoid that one of them appears more important than the other I can do this nicely with color.

Other line attributes are not so easy. A solid line will always seem more important than a dashed or grey line and a dashed line more important than dotted one. Trying to change the dash and dot pattern so that they have similar grey values makes them hard to distinguish. I find color is the easiest way to distinguish things without introducing unintentional order.

I watched a youtube video where a color blind guy in his 50s was given a pair of EnChroma glasses for color blindness, put them on, and had a strong emotional reaction, like a deaf person hearing for the first time.

Then I read the wikipedia article (https://en.wikipedia.org/wiki/EnChroma) that says "they do not restore normal color vision, and claims in excess of this by the manufacturer have been characterized as marketing hype ... They are simply a very expensive pair of hunting glasses ... How could they possibly work? The answer is that they can't."

I liked the video and now my feed has dozens of similar ones with similar strong reactions. If they don't work why the reactions? Am I missing the videos where they just say "meh"? Is it a placebo effect or maybe they're just playing it up for the gift givers? I guess the test is whether they continue to wear the glasses for long.

Im red green colorblind and have enchroma glasses. They work by reducing the other colors to balance with the reduced colors.

There are lots of reddish brown things that are actually red. I wear mine daily, but if I didnt, I wouldnt miss them.

With the glasses on I can see subtle red tints that I cant normally notice. For whatever reason it doesnt help much with green.

You might want to spend a few more minutes on finding out what those actually do. Yes, of course they don't restore normal colour vision. They can't possibly work iff that's the goal.

Look at the frequency responses of cone cells in a human with normal colour vision: https://en.wikipedia.org/wiki/Color_vision#/media/File:Cone-...

Those already have a very high overlap. A lot of people with red-green colour blindness still have those two types of cones working quite well individually, but the overlap is even more extreme. What these glasses do is filter out photons that fall in these overlapping regions. This amplifies the difference in responses from different cone cells.

I don't know about what marketing claims were made by that particular company. Maybe some were plain wrong; maybe they were correct but overhyped with a tendency to mislead. Maybe some of those YT videos aren't as ‘organic’ as they seem, but dramatic reenactments incentivised by some PR douche handing out free samples. All I know is that it's not implausible that someone is happy because they can finally tell grey from purple for the first time. I'd encourage interested consumers to check out other brands first, but no idea if those even exist in the consumer eyewear market. Maybe Enchroma are sitting on a patent? Anyway, try before you buy.

By the way, I would have been surprised if that Wikipedia article actually said ‘they can't possibly work‘. That's not the case — it contains a quote with that claim. It's cool to shorten a quotation to just the relevant parts, but please try to not invent ‘alternative facts‘ in the process.

> like a deaf person hearing for the first time

Yeah, definitely not. Once upon a time, my headphones and earphones failed simultaneously and I spent a couple of weeks listening to podcasts through busted earbuds, in shit quality, mostly one ear at a time. Then I got proper IEMs and finally could hear music again. In stereo. Experience all the instruments. That felt quite good. I guess it's more like that. Except it would be for the first time ever. I can see how that would prompt an emotional response.

I tried contact lenses for colour blindness as a kid (No idea if they were made by EnChroma).

They made everything seem so much brighter and more colourful, like someone dialed the saturation notch right up.

I didn't like it. Everything was so colourful it felt like it was giving me a headache. I guess I could probably have gotten used to it if I'd kept with it, but I just didn't believe it would make me able to recognise colours correctly - I mean, surely my brain was already pretty much hard-wired to comprehend course a certain way? And I remember they were expensive, and our family wasn't exactly well off, so I declined.

Anyway, as a middle-aged man now, I don't feel like it's been significantly detrimental to my life. For the occasions I need it, I use apps to check the RGB values of things, and I can roughly figure out colours, but in general, yes, it's an impairment, but just doesn't feel like it's a big deal.

A former colleague of mine who was also red/green colourblind had a pair of these and I borrowed them for the weekend. I was pretty underwhelmed to be honest, couldn’t see much difference. Maybe they work better for certain types of colourblindness.

I'm yellow/blue blind in my dominant eye. This article rings true for me, although with different colour choices. For example, I didn't realize the halo thing was common, but I see it when looking at bright pink things.

The larger an object is, the more likely I can tell from that eye alone what colour it is. Mostly I err on the side of cyan - any colour near cyan (green to light blue) will invariably look like a single shade of cyan to that eye, so those colours are pretty much indistinguishable if overlapping like in the text examples. Eg: At night, the blue lights on buses and the green "go" light at intersections are the same colour to that eye - cyan. Until they get close (large) enough and then I can tell that they are different colours.

There is a huge difference when I do A/B comparison in either case, but when looking through both eyes simultaneously, I don't notice the deficiency at all. The brain decodes colour and fills in the blanks in unusual ways.

R/G colorblind here. This is simply the best writing about my color vision deficit I have ever read. The charge status LED thing makes me crazy and I now wonder if I could use diffusion/ground glass or film over the LED with a little gap to, in effect, enlarge the color field of an LED so that I can better discern the color.

This is a super interesting article! However some parts of it are... well they are true for me as well, even though I'm pretty sure I'm not colorblind.

This, in particular:

> Another consequence of all this is that I see very little color in the stars.

It's all white for me... Am I missing colors?

"Another consequence of all this is that I see very little color in the stars. That makes me sad."

WTF, Am I color blind too? I pass regular color blindness tests with ease, but I have never seen any color in the stars. Not with the naked eye at least.

With the naked eye, stars can be seen to have subtly-different colors. Other commenters have pointed out that Mars is rather distinctly orange/red, and easily visible in the skies of North America now.

One example between stars right now is the two brightest stars in the constellation Orion. Where I am, in Indiana, USA, Orion rises around midnight EDT (~0400 UTC) tonight. It will rise earlier is you are east of me, and will rise earlier as we get into northern-hemisphere winter.

Betelgeuse (pronounced like the movie "Beetlejuice", but with "bay" instead of "bee") is Orion's right shoulder. Since he is facing towards us, it is the star in the top-left of the constellation. Betelgeuse is a red supergiant, so it is both distinctly bright and distinctly red when compared to the other stars in Orion.

The star I like to compare Betelgeuse to is Rigel, Orion's left knee (bottom-right from our point of view).Rigel is a blue supergiant, similarly bright to Betelgeuse.

Here's an excellent color-enhanced mosaic image of the constellation by Rogelio Bernal Andreo, which clearly shows the red-orange-ness of Betelgeuse compared to the other stars in the constellation:

https://upload.wikimedia.org/wikipedia/commons/4/47/Orion_He...

More information about the image can be found here:

https://apod.nasa.gov/apod/ap101023.html

To the naked eye, I (and other typically-sighted people) can distinguish these colors easily when looking for them. Their color ranges from red/orange to white to sort of sky-blue. This is because starlight is black-body radiation, which creates a very specific scale of colors. Here is an image showing the typical colors of stars, and their corresponding surface temperatures:

https://en.wikipedia.org/wiki/Black-body_radiation#/media/Fi...

Rest assured that to me, at a glance, stars are just bright white dots. Even knowing that the colors are there, I still have to stop for a second and look at them in order to see it.

I have also red-green color blindness and it makes me really mad that a lot (like 90%) devices have a tiny LED that indicates if it is charged and the LED changes color from red to green when it is fully charged - I have to ask my kid or wife what color it is.

Please please, if you work in hardware, make it a red/blue or green/blue colors for empty/fully charged, or make it blink, anything, just not tiny 1 pixel size red or green color (or amber/yellow, they are equally hard to distinguish for people like me from green).

Turn off light when charged, works for Panasonic batteries charger.

Unfortunately the light also turns off when the charger is broken, or unplugged.

I've been wondering if syntax highlighting has a different amount of usefulness for colorblind people and whether it would be worth it to have a "font highlighting" system for different things. I already use bold for curly braces and italics for square braces since I use a small font. I'd like to try it. But vim chokes if the fonts are different sizes and sublime only allows one font at a time.

This was a great read. I am red/green colourblind and it was fascinating to learn about how edge detection plays a key role - I’ve always thought it was interesting how I struggle to tell colours apart on a graph, but it’s usually quite easy if there are two blocks to compare.

I do also find that it’s quite hard to match up two similar colours in the red/green spectrum, regardless of size, unless they are actually next to each other. I also struggle to differentiate between bright green and yellow, dark green and brown and sometimes blue and purple; to the point where I don’t know which of the two to call something. This I guess is not related to edge detection.

As an aside, I love this kind of content - well written, interesting and not on some bland platform like Facebook or Medium. It reminds me of the sort of stuff I used to discover with Stumbleupon. Any recommendations where to find this kind of stuff, except for on here?

> I see red and green just fine. Maybe not as fine as you do, but just fine. I get by. I can drive a car and I stop when the light is red and go when the light is green.

Yup. If I had a pound for every time someone would hear I'm R/G colourblind, hold up something red and go "so what colour is this then?".

> In short, color detection when looking at small things, deciding what color an item is when it's so small that only the color difference signal at the edges can make the determination, is worse for color-blind people. Even though the colors are easy to distinguish for large objects, it's hard when they get small.

Like the author of the article I am partially red-green colorblind.

I found it particularly Illuminating to understand why the amount of colour makes a difference in the ability to distinguish between them. It's someting that I have repeatedly observed on my own, but I could never properly explain.

Interesting thing about people with deuteranomaly, is that in some situations we can utilize luminance and S-cone data better than most people with normal vision. That's how Ishihara hidden plates work (numbers that are visible only with color vision deficiency). But some normal trichromats can also read these hidden plates: https://jov.arvojournals.org/article.aspx?articleid=2135713

That's not how I read it. Normal trichromats see noise on L/(L+M) axis, for red-green color vision defective that axis is L/(L+L). We use S/(L+M) axis and luminance differences. Some normal trichromats can see through that noise.

To understand how it feels lets compare with a superior vision of birds [1]. "That bird is mostly black", I see what it does not see.

With normal vision colors pop out. I've checked once emulation, animal tongue is so red (displayed as hot pink), the brightest point on the picture. Meanwhile it is "just red" for me.

[1] https://www.google.com/search?q=how+bird+see&tbm=isch

There have been plenty of times where I (r/g colourblind) have been able to see paint mis-matches on red coloured cars where people with normal vision haven't seen an issue, and I've been able to tell at a distance which panel has been refinished. I think the input/output curve of my red perception is non-linear compared to normal colour vision, and while on a lot of that scale it is a deficiency, in some situations, I have improved sensitivity.

Having said that, I'd trade in a heartbeat, so I could see bloody charging LEDs properly.

If you're colorblind you should know that since 2018 or so there are special glasses to aid your specific type of color blindness. You can buy them, put them on and in 3 seconds you have color differentiation where previously there was not.

One friend once told me that he would see 100% red down to 70% red as the same thing.

So after certain point, the intensity of red didn't matter.

Summer studies show that colorblind person don't get fooled by camuflage.

Anedoctaly, another friend got a LCD tv with a red dot in the middle of the screen. He sold the tv to the first friend because he had no problem with that dot...

I also have this ind of slight red-green color blindness. It doesn't bother me in practice except for a few unimportant edge cases.

One of them is color maps. I wish people just used brightness maps instead, there's no value added by changing brightness gradient into a hue gradient.

The worst by far are multi-hue gradients.

> I can drive a car and I stop when the light is red and go when the light is green.

I'm also slightly colorblind and pure green light would be harder to distinguish from distance (not critical because there is also light position, but still). That's why traffic lights usually have cyan tint.

Discriminating a sole blinking-red vs. blinking-yellow light is a bit hard , but in practice I get it right.

I see traffic lights as red, yellow, white. At night from a distance this can be a problem.

Good to consider everyone when designing interfaces.

As for degrees, I had a Cub Scout making a craft project. He held up a pipe cleaner and asked "Is this green?" It was black. Jet black. I said "No, its black". Oh. He selected another (green) one and all was well.

So it can be complicated for some.

Is there a more precisely evocative term? color-disability, color indistinguishment. Color vision-impaired? Vision/visual-color impaired. Impaired color perception.

The word "blind" implies, at a first impression, nothing to be done for a visual use-case.

Colour (vision) deficiency.

Being tritanope, my favourite euphemism is 'chromatographically challenged'.

I once got married just to know whether my battery pack is charging or not.

  I see very little color in the stars

I can't see any color in the stars either. All of them are white. Are you people seeing colored stars ?

I'm not colorblind, but the only colored star I remember seeing is Betelgeuse - it's bright and easy to find. Mars is also usually reddish but it keeps moving, so it's harder to find (for me) - also it's not a star.

I think seeing the color of stars is more a question of how dark your night sky is, and how many stars you recognize.

This article is high quality - learned a lot by reading.

I'm r/g colorblind, the biggest takeaway from this article is that, there are different colors in the stars??

Nice article. Small correction, humans are not old world monkeys (or any kind of monkey). We are apes.

Interesting, so English language has two words for them. e.g. in Polish both are "małpa" (and usually translated to monkey), similar to turtle and tortoise, for us it is a single world "żółw" (and usually translated to turtle).

Ape could be also translated as "człekokształtne" ("humanoids"?)

It's partly an issue of language, but "old world monkey" and "ape" correspond to specific scientific classifications as well.

I have fairly severe deuteranomaly, and boy are the default label colors in Jira hard to see.

want to piggyback onto this thread and request someone to help me test my ui.

link and creds is in my profile. you can leave feedback here or right on the site.

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