Review of Open Source Color Blindness Simulations | Hacker News Reader

Review of Open Source Color Blindness Simulations

daltonlens.org

65 pointsnburrus11 comments

I remember myself testing the colorblindness tool in Gimp 15 or so years ago and concluding they were useless since there was no difference between the images with or without, hehe.

Wasn't until a few years later that I realized I was severely affected I think.

(As for why the obvious explanation eluded me I think it must be because compared to my brother who could help in the garden because he couldn't see the fruits we were supposed to pick I have very good colour vision.)

I have deuteronopia (basically see almost no green), and to my eyes, the blocks marked Marchado, Vlenot, and Brettel are nearly indistinguishable from the original, but the Coblis blocks are not as close. I can see a difference.

Similar for me with protanomaly. I can see a small difference for Machado, Viénot and Brettel (the most saturated red becomes green-ish), but the difference is more significant with Coblis V2, and pretty much just broken with Coblis V1.

To be fair part of the failure of CoblisV1 could be the lack of sRGB/gamma correction, but none of the implementations I found online had it.

If you want to play a bit more with the simulations of Brettel / Viénot / Machado this article has more images: https://daltonlens.org/evaluating-cvd-simulation/

I wish the original article had sliders on the images at the end like the Ishihara patterns do in your link!

It's interesting that you see differences in those images with protanomaly; with my deuteranomaly I see pretty big differences in the images in the OP but playing with the sliders in your link it comes back as severity 0.9 (i.e. I can only ever see numbers if the severity is at max).

Thanks for the feedback, added some sliders to the article, it indeeds help!

That's to be expected since the Coblis methods, particularly the v1/ColorMatrix version, are known to be very inaccurate. Unfortunately, it's usually the top search result for "colorblindness simulator," which leads folks with normal color vision who try to check for color vision deficiency accessibility to conclude that the images they're checking are accessible in cases when they're not.

I wish the comparisons allowed you to flip back and forth between the versions in a single location on the screen. That would make it much easier to spot the differences.

If you're having trouble seeing the differences between the comparisons...

Wouldn't it be still noticable? For a color blind person, it just doubles the effect.

Some color blind people will have difficulty seeing the differences between some of the different simulations, between the simulations and the original, and both.

Someone with normal vision will have no problem with ambiguity throughout, and wouldn't be asking to be presented the images in a different way to help them see the differences.

Thing I wrote about my own colour blindness a few years back, for anyone here who's never really dug into it before:

https://mcconnellsoftware.github.io/colourblind-in-software-...

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