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Is it me, or do the protanopia (top right) and deuteranopia (bottom left) images look identical? If I’m colour-blind this would be a weird way to find out.


All except the blue-yellow (bottom right) images look the same to me, in both examples. And van Gogh's 'Starry Night' 'filtered to simulate colour blindness' looks the same before as after. I am colour blind.

Now, if only someone could filter it to simulate non-colour-blindness for me, so I can see what they see!


https://www.allaboutvision.com/conditions/color-blind-glasse...

allaboutvision.com/conditions/color-blind-glasses.htm


I'm curious how well that can work, but not '$200 to $450' curious. I wonder how many people actually have enough of a problem with it to get these - it's not like you're suddenly going to be allowed to fly fighter jets after all.


I'm colorblind (strong deutan) and bought a pair of EnChroma sunglasses after trying out a simpler system that pretty much just used a combination of colored lenses (the lenses would have had to be two different colors and would basically look like 3D glasses).

Allegedly the EnChroma glasses work better the weaker your color deficiency is (i.e. they work worse the worse you already are at telling colors apart). For me there's a pronounced effect but it's mostly through shifting all colors more into violet and yellow.

Using them was the first time green LED traffic lights appeared "saturated" to me although yellow traffic lights appeared a bit darker than normal. A clear blue sky appears vibrant but with a noticeable violet tint. Flowers look neat as reds and purples "pop" in the same way pure blues and yellows do normally. I can tell whether lawns are healthy or dried out.

But they don't "fix" my color vision. Of course not. They can't add color where I'm physically unable to perceive it. They wouldn't allow me to pass most colorblindness tests or operate machinery that requires normal color vision. They can however modulate some parts of the visible spectrum so others stand out more. And they're really good at that.

I've had my EnChroma sunglasses for a few years now and I use them instead of regular sunglasses in most situations (except when I expect they might get damaged). I would probably buy them again. I considered buying regular EnChroma glasses but I've heard the effect isn't as strong and as I'm already not in the group benefiting the most, I worry the effect wouldn't be good enough to justify the price tag. YMMV.

EDIT: I'm fully aware of the dramatic reaction videos that made them popular all over social media for a while. I saw them after I found out about EnChroma and after I had already decided to give them a try but before I was able to do so. If anything, these videos made my experience of first using them more underwhelming. Yes, I could "see" purple in a different way than ever before, but knowing the reaction videos and knowing the person I was with knew them almost triggered a form of imposter syndrome because I simply didn't experience the overwhelming sensation the videos suggested I should perform.


Although I suppose if you need prescription glasses anyway, why not.

Fortunately I don't need short/long corrective lenses, so there's no way I'd wear glasses just for improving colour perception a bit. Even if they were free (I'd try them as a gimmick, sure, I just doubt I'd want to wear them regularly).


There are multiple apps that claim to do it using the phone camera… but I’ve never tried them, so no recommendation.


Those images, top right bottom left, actually look really cool. They appear sepia toned, which is a fairly common filter effect that invokes nostalgia. It's almost neat that you might see everything that way.

(I'm sure it doesn't always feel that way)


Sepia looks different to normal to me too, so no, but that's interesting!


We made this once:

https://www.vischeck.com/daltonize/

But no one seemed particularly interested. Let me know if you are...


Blue-yellow? The bottom right image of the parakeet appears to be black, blue, gray, and white, with a blush of pink near the beak.


Yes, sorry, I meant the one simulating tritanopia - blue-yellow colour-blindness - not that the image itself was blue & yellow.

(It's just greyscale to me fwiw, as someone non-tritanopically (I've never been sure what, nor the optician, doesn't seem to be cleanly proto or deuteranomoly, perhaps some combination?) colour-blind viewing it filtered to simulate that. On some hand-wavey high level I lack the ability to see what's left after what I can see has been removed, I suppose.)


It's because the cone cells connected to those variants of colorblindness have very similar sensitivities to wavelengths. Check out this diagram: https://en.wikipedia.org/wiki/Cone_cell#/media/File:Cone-fun...

With protanopia, the L cone cell is affected. For deuteranopia, it's the M cone cell.


My college roommate found out when I showed him a joke tshirt with a message in the circle of dots. He thought the joke was that there was nothing there and I was messing with him, then spent an hour on Wikipedia figuring out exactly what kind of color blindness he had.


The deuteranopia is very slightly more orange in some squares.

The visibility probably depends a lot on your display color calibration and how fil spectrum your ambient light is. Incandescent "soft white" and modern imitations, common in household lighting, is usually yellow/orange.


I overlayed them in Gimp as layers and did A/B comparison with other people and neither could detect a change.


Thanks for doing the "obscure science"! Perhaps it was variations in my lighting or optical illusion effects.


They look identical to me too, and I'm 100% certain I have full colour vision.


This is more a test for reading-blindness than color-blindness :D


Same here, and I just took an online test to verify.


They look very clearly different to me, but the difference isn't big. I made a gif of the starry night images: https://p.mort.coffee/jR5.gif

To me, one of the images clearly has a yellow color where the other image has a green-ish color.


It took me a while to see anything other than resizing - but yes, the larger one is ever so slightly greener to me too (I am colour blind, couldn't see a difference side by side).

And I watched the gif prior to reading your description of the difference - I experience this strange phenomenon sometimes whereby the colour of something (or the presence of different colours) morphs in front of my eyes, after someone describes it or claims that it's there. (Red and green bars on a chart for example might all be the same, then someone says 'blah blah in the second red bar' and all of a sudden I can distinguish them, see the red or green that wasn't there before. Or a bridge in London that suddenly looked green when I was told it was called Green Bridge.) I wish it was easier to learn more about it, because I find that kind of fascinating (and mildly 'scary'!) - must surely mean it's not just about the eyes, but my brain is smoothing over some rough edges as though small red/green differences are assumed to be wrong, but if someone confirms them then the parameters are altered.


Yeah, sorry about the resizing and shifting. The two images in the article are different sizes (and aspect ratios!), and I couldn't find a good way to fix it up in gimp without either making everything blurry (cubic interpolation) or cutting out rows and columns (nearest neighbor interpolation).

Your description of how you see colors morphing once they're described is interesting! The brain definitely does a whole lot of complex visual processing which we don't notice, such as filtering out the big hole in your retina which nerves go through, and retroactively replacing the memory of your eyes moving with what you see after they've moved. And your peripheral vision is almost entirely grayscale, yet the brain fills in the colors it expects to be there so it doesn't feel grayscale. It doesn't surprise me that when color information is missing due to color blindness, it will fill in the missing color information from other sources.


I’m color-blind, too. I can see only the resizing difference in the gif; the colors look identical to me.

I haven’t ever experienced the reperception-by-suggestion phenomenon that you describe. But I do think that, when I was young, I gradually became a bit better at distinguishing and remembering colors than I had been as a child, perhaps because having been told that I was color-blind made me pay more attention to colors. “Purple” was a mystery to me when I was ten; by the age of twenty, I could usually distinguish it from blue.


I am not color-blind, but there are shades of colors that, depending either on light source, what other colors are around, or just how I'm thinking about what I'm looking at, will switch back and forth. I can pick out purple from violet, but I have had some clothing that will either appear purple or grey depending on how I am thinking about it (really). Similarly, I have a hoodie that is a timber green that at times appears brown, and a pair of corduroys that are brown that at times appear vaguely purple. I am nearly certain these shifting hue effects of the dyes were intended by the manufacturers.


It's extremely subtle to me - the bottom horizontal stream gets very very slightly greener when it gets bigger. I noticed it first because the starry swirl thing above it, bottom right of the big black thing, seemed to change shape as though the actual brush strokes were different, bit more of a classic star shape emerges. But it's extremely slight, more like the 'what a colourblind person would see' filtering is imperfect than that I can actually see the original.


Parent was talking about the "protanopia (top right) and deuteranopia (bottom left)" cell division pictures, not the Van Gogh on top.


Oh, sorry! I should've read more carefully.

Those do appear to be literally identical to my eyes as well. I made a similar gif of those: https://p.mort.coffee/UIt.gif -- I can only see the noise shifting around a little bit. And GIMP agrees; the RGB histogram looks incredibly similar between the two images (https://p.mort.coffee/tn8.png vs https://p.mort.coffee/t3z.png).


Given one of them is labelled as being a simulation of blue/yellow colourblindness while the blue/yellow in the original image look very distinct, I suspect there's just been an error in producing the composite there.


They're talking about the image with the 4 versions of the call-divisions. They top right and bottom left there look identical to me too


If you were colour-blind, the full-colour image (top left) would look nearly identical to one of the other three.


If you were totally colour-blind (by far the rarest sort), I suppose it would.


It looks identical to both protonomaly and deuteranomoly simulations to me. I am colour-blind, but not 'totally' if you mean grey-scale only - just that certain shades merge together/look like the wrong colour.


The "grey-scale" color blindness is super rare. The "just that certain shades merge together" color blindness is what usual color blindness is.


I know, I was replying to 'if you were totally colour blind (by far the rarest sort)'.


I guess by totally you mean the strongest case of a particular kind of colour-blindness, not achromatopsia. Fair enough, I could have said similar. I just wanted to clarify which image is the one they should compare against.

However, if colour-blindness is not so strong for most people, then these articles should depict a lesser form of colour-blindness as well, to more accurately convey the experience. I don't think I've ever seen a post on colour-blindness that did.


seems normal: different mechanisms creating almost the same symptoms. a few different sources from googling protanopia vs deuteranopia:

> Why is protanopia like deuteranopia? Red and green colorblind deficiencies (deuteranopia and protanopia) are very similar, as these cones often overlap. Therefore, protanopia and deuteranopia can often eliminate the ability to see both red and green, showing the world in vibrant blues and yellows, as well as very similar browns, oranges, reds, and greens.

> People with deuteranomaly and protanomaly are often incorrectly diagnosed collectively as ‘red-green’ colour blind because both types generally have difficulty distinguishing between reds, greens, browns and oranges. They also commonly confuse different types of blue and purple hues and many other colour combinations.

> The answer is that dichromatic colorblindness is imitated by assuming two of the three types of receptors receive the same light input. In deuteranopia, for example, the assumption is that the neural receptors expecting medium (M) and long (L) wavelength light are both receiving signals from cones with long (L) pigments. This results in the yellow you noticed. Note also that deuteranopia and protanopia don’t result in exactly the same hue of yellow because of the difference between their peak sensitivities. In one case it is assumed all signals are coming from L pigments and in the other all from M pigments.


I found a setting in chrome the other day that allows you to simulate the 3 types mentioned in the article.

Seems like there is more variation in chromes filters than the ones shown in the article.

BTW they look the same to me too.

In chrome: console > rendering > emulate vision deficiencies


yup the same to me..

I even overlayed the two images over each other and flicked back and forth between them.. they are identical


Yeah - it looks identical to me too. I already know I am colour-blind but not exactly sure what type.


They are identical to me. I have never showed signs of color blindness in such tests.


They look identical to me too, but I know that I can perceive RGB hues.


The other pictures are better for comparing this.


Yep, looks like they are the same.




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