extension ExtPose

Spectrum (delisted)

CRX id


Description from extension meta

Instantly test your web page with different types of color vision deficiency.

Image from store Spectrum
Description from store Color Vision Deficiency (CVD) affects people’s ability to distinguish certain colors. Estimates indicate that approximately 200 million people worldwide are affected by some kind of CVD. Individuals of Northern European ancestry, as many as 8 percent of men and 0.5 percent of women experience the common form of red-green color blindness. This extension helps you to test web pages for people with different types of CVD. It's particularly useful for websites with data visualisations, because some colors may not be distinguishable from other colors in the charts. Flash enabled websites are also supported!

Latest reviews

  • (2021-09-03) Najla Nur Ariqah: Actually got recommended to this extension from an article, I just feel i wanted to try it although i don't need it.. But to be honest this extension help my eyes from getting hurt than made it dark theme (i don't really like dark theme, also this is just my opinion). Btw beside of this extension last update is 2017, I saw some people saying this "not working", Idk if this because it's not working on some website or they forgot to refresh page. Because you literally need to REFRESH or RESTART BROWSER anytime after installing an extension. Note: btw on google search, I saw it's working but,, with the low-contrast mode it's make some things of article being highlighted (idk how to describe it) iis that normally like that or..? I don't have problem at all with that I just want to mention that. (here the photo since I am not good at describe thing:https://i.imgur.com/2WSyvmq.jpg)
  • (2021-08-17) Beatriz Albino: Hi there! Is this project open source? could you send me the link? :D
  • (2019-10-10) Archi Cad: I'm a color vision expert and I must say this colorblindness simulator has a lot of shortcomings. It shows protanopia red way too dark, as well as deuteranopia red. It also shows protanomaly and deuteranomaly red hues way too reddish than what they truly perceive them. Their reds are much more closer to yellow hues. Tritanomaly simulation is almost the same as normal vision which is totally wrong. Tritanopia simulation is also wrong since it shows that they practicaly see a whole hue circle with some saturation loss, while in reality they only perceive two hues - our reddish pink and cyanish hue. All in all, if you want to use this extension, use only protanopia and deuteranopia simulations since those are the closest to being correct, but keep in mind that reds are represented darker for both types than what they should be, especially for deutans who see red wavelengths much brighter relative to green wavelengths (they still see both colors as yellowish hues) compared to normal vision. Deuteranopia simulation is actually very close to being correct if it was named protanopia, it just needs a slight double grays (around pink and aqua green) position shift.
  • (2018-08-06) Nerdy Maple: I had to restart my computer, but it works. It has a nice range of colour blindness to chose from, and you don't even have to reload the page as it works instantly! I would recommend this to anyone.
  • (2018-02-16) Shadowbandit: Works well enough, but I have to reset it every time I change the page. I saw that you were going to update it to where it stays, even after a refresh, but until then, I recommend other extensions, such as colorblinding, which can do the same thing, only it does what your app cannot.
  • (2018-01-22) Just Nierninwa: Shame it doesn't work on YouTube videos when you open them in full screen. But it's nice that it's instantaneous and doesn't need reloading the page! :)
  • (2017-07-04) Malgorzata Felis-Maj: Hah! It didn't work when I've added it to my browser. I restarted the computer and it works now :)
  • (2017-05-09) Jordyn Bonds: Quite helpful! Just wish it worked on local files.
  • (2017-04-26) David Mills: I enjoy the simple, clever technique for applying the filters!
  • (2017-04-09) Jonathan Gregson: It does the job. One thing I would suggest is to use the common name for the type of color blindness. I wanted to test what it would look like to specifically red-green color blind individuals, so I had to Google red-green color blind to figure our that "Deuteranopia" is what I was looking for. It would ideally be written as "Deuteranopia (red-green)" in the menu.
  • (2017-02-06) Jim Parrillo: Fantastic plugin for my UX testing!
  • (2016-11-17) Ken Goulding: This used to work great, but as many others have commented, seems to have stopped working (Version 54.0.2840.99 m)
  • (2016-11-03) Ash: Great simulation, but lacks options and I'd like to be able to browse my site without having to re-enable it after every single page reload.
  • (2016-10-29) Paul Rescigno: Doesn't work at all for me for some reason
  • (2016-09-27) Djame Goldston: This should only be one of many color accessibility tools that you use. It's nice to have as a design/development check, but it cannot replace more sophisticated methods. 2 critical issues that need to be fixed: • Color overlay causes clipping during scrolling on some sites • Needs an on/off switch as DOM is still affected during "Normal" mode
  • (2016-08-28) Lily Wilson: great idea, but the fact that it doesn't change background colors/images makes it pretty useless.
  • (2016-07-03) Ely V: Had to disable it because it breaks some sites using javascript.
  • (2016-06-30) Stefano Bua: Simple and does exactly what it says! The checked mark resets every time i pull up the menu.
  • (2016-06-08) Sarah D: It's not working at all and I can't figure out why
  • (2016-06-06) Niko Storni: this extension helps me when i want to show my friends what i truly see compared to what they see. It's extremely efficient!
  • (2016-05-03) Jay None-of-your-business: Works great, BUT, causes conflicts with JIRA (by Atlassian). If this is fixed then it's a 5-star plugin.
  • (2016-04-14) Jake Riley: EDIT: You have to refresh the page. Previous: 1-star Does not seem to work. "Options" is greyed out.
  • (2016-04-04) Have used this in the past but now it breaks Jira/Confluence. I couldn't view attachments to tickets, so I had to disable this extension.
  • (2016-03-24) Lucas Francois: How to show people what I see, I love it ^^
  • (2016-03-13) Eric Scoles: I don't have a way of assessing how accurately it represents the colorblind experience, but it does something and is straightforward in operation. Caveat: this does not appear to modify all DOM objects. E.g., background images were unmodified, as were some outer DOM containers. So treat it only as a general indicator, don't try to treat is as a real compliance test.
  • (2016-02-11) AxlWolfU / MRP: Excellent simulator
  • (2016-02-09) Bryan Anderson: If you happen to use Jira/Confluence, this extension breaks some editing ability when enabled.
  • (2016-01-04) Drew Cossey: Sounds like a great extension but it doesn't seem to work for me.
  • (2015-12-11) Luiz K.: Very usefull, and works great


21,732 history
3.8 (56 votes)
Last update / version
2017-01-11 / 0.2.0
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