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Sim Daltonism is a color-blindness simulator for OS X. It filters in real-time the area around the mouse pointer and displays the result - as seen by a color blind person - in a floating palette.

What's New

Version 1.1.3:
  • Fixed a crash that would occur on dual-screen setups where one of the two is a Retina display.


OS X 10.6 or later

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Sim Daltonism User Discussion

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Markus Winter Member IconReview+360
Markus Winter

I showed my boss the new FileMaker app I had created for the lab, and he said: "Could you add this info?" which was right there in front of him - that's when I realized he is red/green blind and simply couldn't see the writing. I found Sim Daltonism and since then haven't created an app, a web page, or a presentation without first checking it with Sim Daltonism. Essential app in my opinion.

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Version 1.1.2
Martin Member IconReview+96

Really nice application. I’ve used in the past to test how website designs work for color-blind people. It always worked great and I really appreciate the update after nearly four years, so I could continue to use SimDaltonsim in the future.

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Version 1.0.4
aljuk Member IconReview+69

Brilliant. Very useful for web designers who are into standards compliancy and accessibility (ie. who are into designing properly). Well done.

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Version 1.0.3
WilliamD Member IconComment+7

My son is R-G colour-blind, and I struggled for years trying to understand his world.

Now I can see what he sees, more or less.


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Version 1.0.3
Jibbe Member IconReview+10

I'm color blind and I like this app to show the world I see.
Thanks a lot

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Version 1.0.2
Anonymous Member IconReview

initial launch of your app on a Powerbook G3 Pismo with 640MB RAM running in millions of colors: "incompatible cpu-subtype". apparently your app is has more needs than just 10.3 and millions of colors.

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Version 1.0
Anonymous Member IconReview


A problem, though. When the display window "Funhouses" (Move the view to the window itself... much like in the sample picture), it starts to chug majorly.

I made the mistake of hitting the button to maximize the window size in an (admittedly foolish) attempt to basically get a more firsthand feeling, where my entire screen would be under the effect.

While my whole screen was indeed colorblind, the problem is that Sim Daltonism is showing Sim Daltonism showing Sim Daltonism showing Sim Daltonism. The screen immediately filled up with menubars and the display window lagged to high hell.

Fortunately, the window functions were still passably responsive and I set the window back to its original size without having to force quit the program or otherwise having it crash.

I think it definitely needs some optimization so it doesn't lag so easily, and it should preferably not show its own window in the display

On the more positive side though:
- It didn't crash during aforementioned full-screen funhousing
- It's an interesting concept
- The fact that I can make more than one window and set the filters independently is great.

Reply2 replies
Version 1.0
Michel Fortin (Developer)

Githon, while it would be great if I could take an screenshot of what is behind the window so that Sim Daltonism doesn't show its own windows recursively, I don't think that to be possible. However, I could arrange it so that you see a blank rectangle instead. This would be less distracting.

As for speed, it was too slow some months ago, now it's fine so I can publish it, but it could still be improved. This software is free, but improvements will surely come sooner if I receive some donations.

Thank you for this insithful comment.

Anonymous Member Icon

Only now do I find your response :)

I think a blank rectangle instead of the recursive effect would drastically increase performance, since the funhousing seems to be what makes it chug anyway.

Anonymous Member IconReview

Wow. Fascinating.

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Version 1.0
user icon+0
Version 1.1.1
user icon+10
Version 1.0.5
> 5 6


Current Version (1.x)


Downloads 6,458
Version Downloads 262
License Free
Date 29 Apr 2014
Platform Intel 64 / OS X / Intel 32
Price Free
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