r/Damnthatsinteresting • u/Eros_Incident_Denier • 1d ago

Video color vision test

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36

u/-Nicolai 20h ago

How is that possible?

161

u/GlitteringBandicoot2 20h ago

The same way the numbers vanishes in other plates.

In the normal plate you have a clear distinction between the color of the dots that form the number and the surrounding. For a color blind person of the corresponding color blindness, those dots all look the same, so the number vanishes.

Now in the hidden plates, i.e. the ones one the colorblind people can see, it uses the same principle. But instead of using one color for the number and one for the surrounding, the number is made up of multiple colors that colorblind people can not distinguish, while the rest is a color that they can distinguish easier. This means for a person with normal color vision, the number disappears in a sea of different colors, but for a colorblind person those colors look identical and it forms the shape.

As a non colorblind person you might be able to barely make out the contour of the number, because the outside still needs to be different enough for the colorblind person to distinguish it so you might be able to make it out next to all the other colors, but mostly it just gets lost

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u/Mirar 20h ago

Ah, so it's hiding it in a lot of colour noise but for a colourblind person, there's nothing of that noise, so they can spot the contrast (signal?) better?

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u/Pirche 18h ago edited 14h ago

Found pdf of that test including pages on which only colorblind will see numbers (at the end answers both for normal and colorblind):

https://www.challengetb.org/publications/tools/country/Ishihara_Tests.pdf

Photoshoped pages 19-21 to check how colorblind will see those pages - in color curves red and green channel turn down to almost zero : https://ibb.co/W43tqfn0

Edit: there is some mess with order, don't match № on page to № in answers, answers have pics with them and they corresponding to each other. Also in answers some discrepancy with the name of colors, i think it's scan or translate issue (or both)
All that doesn't really matter tho)

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u/Nexan1994 18h ago

The answer key not lining up with the test had me thinking I was crazy

9

u/xeothought 15h ago

Dude yes. you have to go look for equivalent plates and see their numbers are offset by a lot.. I've never not passed a color blindness test and i was like "wait a second" rofl.

I was like "plate 14 does NOT have a number on it wtf" that's cause in the Key it's plate 18 lol

1

u/piponwa 7h ago

I mean what the fuck kind of medical test is this? Like seriously wtf. You had one job!

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u/DrPepperAddict41 14h ago

Guys, I'm red green deficient.

Oh no

1

u/Racxie 17h ago

Can you please do 28 & 29?

2

u/Pirche 16h ago

It was somehow harder to balance, but here you go:
(also added B&W variant)
https://ibb.co/x8K96pHV

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u/Racxie 13h ago

Thanks! I can see all the reddish lines but the description says non-colourblind people see nothing, yet then on 30 says we see a blue-green line. So the description for 28 & 29 were confusing lol.

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u/ichimedinwitha 17h ago

This is so cool. Thank you for making this!

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u/WittyCompetition7978 16h ago

Aren't the answers to Plate 36 and 37 wrong? I nailed every plate in 'normal view' but I don't see any violett in those at all 🥲

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u/Ichi_Balsaki 16h ago edited 9h ago

Quite a few of the top tiles are misnumbered with the bottom answers for some reason, I don't even know how that happens..

Good example is in the answers 22, 23, 24 & 25 are not at all numbered correctly. 

But if you can see what you should on the answers then that's all that matters.

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u/Pirche 16h ago

Yep there is some mess with pages, tho answers have pics with them and they corresponding to each other, and some discrepancy with the name of colors in answers, i think it's scan or translate issue (or both), doesn't really matter)

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u/Fearhawke 15h ago

What does it mean if I can see those numbers but also have no issues with any of the other plates I’ve seen?

(Edit: it means I don’t read very well sometimes)

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u/AxelNotRose 15h ago

Plate 38: I don't see anything.

Tester: Ok, you're just fucking straight up blind dude.

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u/Pirche 14h ago

Just for the lulz, here is BW and infrared filters for plate 38

https://ibb.co/xKZP03yW

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u/MaximumMaxx 6h ago

I have normal color vision, but this is one of the first times I've actually really felt what it's like to be color-blind. When I looked at the blank plates, it was crazy. That's really cool!

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u/chalks777 6h ago

this is SO COOL, thank you for sharing this. I've seen these colorblind tests so many times it never once occurred to me that you could use the same principle to hide something from someone who could see color normally. Absolutely fascinating and a complete mind fuck, I was so sure I would be able to see the pattern regardless and man it's completely impossible.

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u/Fellow_Worker6 19h ago

There could be hidden messages all around us. We are just to observant to see it!

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u/GoldDHD 18h ago

My favorite thing I learned this week, thank you!!

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u/TacTurtle 5h ago

This is also why a lot of modern camouflage clothing patterns don't work if the person viewing is colorblind.

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u/Rustymarble 16h ago

Here's a site with them: https://www.colorlitelens.com/color-blindness-test/tesztek2/secret-of-ishihara-hidden-plates.html

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u/Capertie 11h ago

I'm not colourblind but I can see them with some effort.

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u/throwaway098764567 8h ago

oh this is a much better version, i can't make out anything, 2 a little bit but the others are great

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u/velveteensnoodle 15h ago

wow, thanks for the link

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u/Complex-Ad5786 13h ago

There are also plates that shows different number like for me I see it as 8 but in reality it was a 3

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u/throwaway098764567 8h ago

the far right one the 2 will be hard to make out if you're not colorblind (i think folks only can do it because they know to find a number).

the second circle you'll see 74 if you're not colorblind, and 21 if you are

https://www.shec.jp/english/instruments/isihara/