Very useful and easy to use. A note for people who don't want to download an extension: you can also right-click, select "Inspect Accessibility Properties", and on the 2nd bar from the top you can click the drop-down menu beside "Simulate:" to do the same.

This extension has been very helpful for helping me and my coworkers understand when colors need to be changed to make them more accessible to color blind individuals.

I find this very useful for accessibility testing my games

It's a good first version. Still behind the ColorBlind - Dalton Google Chrome extension.

Missing:
1) Persistence
2) Visual preview as you select the daltonization parameters (cf. Chrome Extension)
3) Can't get Severity slider to work on FF56beta, regardless of what I do.

Thanks for providing this!

PROS:
As a colorblind individual, this extension works great for daltonizing problematic webpages! It's also given me the chance to show coworkers what webpages look like to me with the handy simulate daltonized feature. Having multiple filters is also cool to explore other forms of colorblindness!

CONS:
I really wish there were a way to persist the daltonization (effectively making a daltonized browser), since I currently have to click on the extension icon for each webpage loaded.

2019 update: I don't think the simulation feature gets enough attention. I have sent this to all my designer friends who make websites, and it has been really eye-opening for many of them, not to mention useful to quickly check if their designs are CVD friendly. So if you know anyone in graphic designers, tell them about this add-on!

"HOLY SHIT IT WORKS! AND I CAN TWEAK IT!" - me, five seconds after installing it and trying to daltonize on a color-coded map on Wikipedia.

(tip for other users: if wikipedia appears to break, you probably are looking at an SVG image. Click through to the PNG to be able to daltonize it)

I've tried other comparable add-ons before, they all worked rather poorly. This is AMAZING! Thank you so much!

One small tweak I would suggest to the developer: add a big quick-toggle button on top of the menu so switching between daltonized/normal view is just two quick clicks/taps away. Searching for the correct radio button is a comparative pain - look up "Fitt's Law" if you're curious about the theory behind that. If you have a github repo I'd love to help out!

Thanks again, this is fantastic!