ColorBlindExt – Better Web Accessibility for Colorblind Users

Have you ever wondered, if you can’t see certain things on a website because of your color blindness? This time is over now—at least for colorblind Firefox users.

The Firefox add-on called ColorBlindExt was released just recently and is a great support to discover things which you couldn’t see up to now. The developers describe it as follows:

This extension helps color blinds while browsing the web, by processing images and text on the page according to the type of user’s color blindness. Color Blindness detection test is included for creating awareness among people.

After installation (see further down) as a first step you should take the color blindness test available through the newly added menu called ColorBlindExt. The test is based on Ishihara plates and will tell you, which type of color blindness you are suffering from. It detects protanopia, deuteranopia, tritanopia and even monochromacy, which means you are completely colorblind.

After taking the test the filter will be set according to your results. This can be changed at any time. Also the filter can be completely enabled or disabled however you like.

ColorBlindExt - Filtered Image
ColorBlindExt – Filtered Image

ColorBlindExt lets you choose to filter whole pages. This can be done either automatically or through the context menu, clicking with your right mouse button anywhere on the page and choose Filter page.

On the other side you can only filter images whereas a little window pops-up, showing you the filtered image by itself.

Personally I like the image filtering on demand. Through this option, which is also available on the context menu when clicking on an image, pictures and diagrams can be enhanced according to my type of color deficient vision.

The developers took the image filtering even one step further. Through the settings you even can adjust the level of deficiency and a choose from a noise reduction and sharpening option. This lets you play around and find the settings which fit the best to your personal color vision.

The tool also has some limitations, which don’t really restrict the usage to me when I look at them.

  • Page contents like flash objects, applets, media players can’t be filtered, it is out of scope.
  • Only elements accessed by DOM are processed.

Unfortunately the installation isn’t a single click and run. I tried to summarize all requirements including the links to get the latest software if you are missing some of them. I hope this helps you to get your colorblind webpage filter up and running without a hassle. Be aware that you need administration privileges if you have to install new software like the Java runtime environment.

Installing ColorBlindExt in 5 Steps

  1. Firefox
  2. Java Runtime Environment
  3. Java Advanced Imaging
    • Version: 1.1.3 or higher
    • Check: Start → Settings → Control Panel → Add or Remove Software
    • Download: – JAI for JRE
  4. Firefox User Registration
    • Why: ColorBlindExt is not yet available as a public download. It is accessible through the Firefox Add-ons sandbox, which is only open for registered users.
    • Registration Form: Firefox Add-ons: New User Registration
  5. ColorBlindExt

Hopefully this tool will help you to access some websites more easily than before or to read some colorful and up to now undistinguishable chart lines. And I also hope this tool isn’t used as an excuse for web designers to disregard accessibility, especially concerning color blindness.

Looking for Children Games Playable with Severe Color Blindness

Keren contacted me, because her son is severely colorblind. He can’t really play basic games as every children game is in color.

What she is looking for are some board games for her eight year old son, where he could pick up the enjoyment of playing games. Because everything heavily relates to colors, this is not an easy task to accomplish.

I have a son that is colorblind with red, green and blue. He can see colors which have a yellow base. This has made it very hard for him to play basic games as every childs game is in color. I have tried every resource in aid to get him the simplest game and now am writing to you to ask if you know or have any games to your knowledge that he would not have difficulty in playing. His age is 8 and has never done jigsaw puzzles, or played board games.

Concerning the color blindness of her son we could at least find out a bit more of what type he is suffering from. This is important because for you, as a mother or father of a child with a color vision deficiency the first step should always be to try to understand what your child really sees. With this in mind it’s much easier for you to help your child and for your child to tell you about his/her problems.

After asking for more details she wrote me the following sentences. They show us some nice insights what it means to live with a colorblind child.

My son has never spoken in color names and as for his crayon box I have had to label every color. With all his school writing books I have to photocopy in black in white as he is not able to see the pale blue lines he is meant to write on.

All this descriptions point into the direction of some kind of achromatopsia. People suffering from some type of achromatopsia have at most one type of color receptors they can perceive colors through. Therefore they see either only in shades of gray or, when suffering from blue cone monochromacy, can see at most some shades of blue.

This of course means, that children suffering from achromatopsia can only play games which don’t rely on colors. Or the colors must at least be easily distinguishable when transformed to shades of gray. Here is a tip how you could test this:

  1. Take a digital picture of all the game pieces.
  2. Upload the picture on your computer.
  3. Transform it to a grayscale picture (most picture programs support this like the free available Picasa from Google).
  4. See if you still can distinguish all the different parts of the game.

Unfortunately I don’t have that many children games and don’t know of any which are playable even with the handicap of not perceiving colors.

Do you know of any games? Please add your ideas in the comment section to help not only Keren but also all other mothers and fathers facing the same challenge.

Colorful Peacock

I enjoy going to the zoo very much. And as we are a big family now we even have a season card for the local zoo.

Christopher wrote about Finding Color at the Zoo. So what does a colorblind guy do with his camera handy and looking for some nice shots to take? – He is also looking for colorful pictures; even if this sounds a bit contradicting.

Here is the most colorful picture I took at my last visit. It’s the very colorful eye on the tail of a peacock.

Peacock Eye
Peacock Eye

And here are the colors I can perceive through my colorblind eyes. Starting from the middle going outwards.

  • very dark blue, almost black
  • dark blue
  • light blue
  • reddish-green or brown?
  • yellow
  • again a light blue

Now it would be interesting to know: How far away are my colors from to the reality? And what colors do you see?

Market Research on Internet Accessibility

Criteria Fieldwork Logo
Criteria Fieldwork

Adam from Criteria Fieldwork contacted me today. They are looking for people who would like to join a market research study into internet use, and it’s accessibility for individuals, who have certain impairments, that may or may not effect their use of the web.

Specifically they are looking for the following types of people:

  • Visually impaired individuals.
  • Individuals who have Dyslexia.
  • Individuals that have mobility impairments.

I suppose at least some readers of Colblindor best match into the first group. Unfortunately I’m not living on the island and as the interviews take place in a North London location, or in your home/office close to this, I can’t join. But maybe you have some time this Thursday 14th, Friday 15th and Monday 18th. The research will consist of one-to one interviews that will last up to one hour.

Not forget to mention you get a thank you cash out of £40.00.

Unfortunately it is the nature of market research that we are unable to disclose the end goal/ purpose of the research to potential. As we like each participant to have an un biased approach when taking part.

So we won’t find out more about this study. But if you like to see what it is all about and are living in the area, just either add a comment to this article or contact me directly. I’ll get you in touch with Adam.

Police Officer – Does Color Blindness Matter?

“Can I become a police officer even when I’m colorblind?” This is a common question among colorblind young men, when dreaming about a career at the police department.

This article will tell you, if color blindness really matters when you want to become a police officer. First we will have a look at some main factors and possible test methods. After that you will find out more about local regulations concerning color vision and some actual job offers seeking police officers. An in the last part of this article I will list your 6 steps you have to walk through to become a police officer despite your color blindness—or at least to make sure you check all your possibilities.

Imagine the following situation: A police officers witnesses a theft and reports it to the police station. “The suspect is about 35 years old, has brown, dark-brown, no black hair. A orange, I mean green shirt; or was it yellow-red. And blue, almost blue, kind of blue trousers. Skin color—oh don’t care about.” I know, it doesn’t have to be like that if you suffer a mild color blindness. But with some types of severe color vision deficiency this statements are coming closer to the truth than not.

Color blindness is not a definite no go for becoming a police officer, but it’s certainly a big handicap. Before we have a closer look at the topic and the differences in some countries and police departments, you might like to read this story of a colorblind police officer and his personal career.

If you are suffering from some kind of color vision deficiency and want to become a police officer, there are several factors to be considered.

  • Type of color blindness. There are different types of color blindness. The strongest form is called achromatopsia, whereas you can only see in shades of gray. This would certainly disqualify you from being a police officer. For the other types like red-green and blue-yellow color blindness it mostly depends on the factor listed next.
  • Severity of color blindness. Is it only a mild form of color blindness or are you a dichromat, who have only two different color receptors compared to three with normal vision? Mild forms of color blindness are often not even recognized by the person concerned. Only by taking some tests, they’ll find out about it. It definitely depends on the severity of your color vision deficiency, to make a judgment about your fitness to be a police officer.
  • Local recruitment regulations. Different countries, states, cities or police departments have sometimes different recruitment regulations. Most often this includes also some restrictions concerning color vision ability. Check your applicable regulations.
  • Recruiting staff. And last but not least, it depends either on the person who is recruiting you or on your new boss. In the end they will decide, if you are the right person for this job or not. Maybe if you just fit in, they will bend the rules to your advantage.

If you apply for the job as a police officer, this will almost ever include any form of color vision test. Most often this is done with an Ishihara plates test, but also Farnsworth tests and City University tests are in use to test your eye sight concerning color blindness.

Often people say, they just cheat on those tests and that will do it. I think, this isn’t the way to go. What, if they find out afterwards, or you annoy your partner because you can’t see the colors you should? And what if they will find out during the test, because cheating isn’t always easily done? I recommend to just be yourself. If it is the right job for you, you will find your way with legal methods.

I would like to point out some regulations and job offers I found. You will see, that there are different wordings used when talking about color vision ability and it’s not always obvious what it really means.

Color Vision Deficiency Regulations for Police Officers

To start with I would like to point out this story of a colorblind police officer applicant written down by a chief of the Berkley police department. It shows very nicely, that it’s not always easy to make a judgment and that there are possibilities even for somebody with a color vision deficiency.

In the United States, the New York State Police writes in their qualifications notes, that color blindness is disqualifying. The Washington State Patrol Trooper formulate it with ability to distinguish colors and be free of color blindness and night blindness. A bit less restrictive is the formulation used for recruiting at the Los Angeles Police Department: Candidates must be able to accurately and quickly name colors. A whole battery of tests has the City of Falls Church requiring that Candidates must pass near vision, color blindness, darkness perception, night vision, and peripheral vision tests. And on the other side we have the very concise formulation NO color blindness of the Portsmouth Police Department.

If you jump over the Atlantic Ocean and have a look at some regulations concerning the recruitment of police officers in the United Kingdom, it looks a bit different. According to policies of the Police Service of Northern Irland, an applicant must have 7 out of 10 correct replies in the City University Colour Vision Test. The detailed eligibility requirements for color vision of England and Wales read as follows:

Monochromats should be rejected. Mild anormalous trichromats are acceptable and should be treated as normals. Severe anomalous trichromats and dichromats are also acceptable but should be instructed in coping strategies.

Whereas color vision should be tested with the Farnsworth D-15 test and applicants should not wear ‘color correcting’ lenses during the color test (eyesight standards for police recruitment). A similar wording is used in the eligibility notes of the British Transport Police.

As the last station, we have a look at Switzerland, the country I’m living in. The regulations I found are the most fuzziest ones. The Kantonspolizei Zürich is looking for people with some Farbwahrnehmungsfähigkeit (ability of color perception) and the Kantonspolizei St.Gallen states that aspirants must have in der Praxis ungestörte Farbwahrnehmungsfähigkeit (undisturbed ability of color perception in practice). This is free to interpretation.

Police Officers Job Offers

Looking at some actual job offers for police officers, you will find some similar or even stronger wordings as in the regulations mentioned above. The City of Manteca expects you to be free from significant color blindness and also the City of Pasadena states explicitly, that you have to be free from color blindness. Compared to this the formulation chosen by the City of Ames sounds a bit less restrictive: Vision cannot be inhibited by color blindness or night blindness.

But anyway, job offers seeking a police officer are most often including one of the wordings above and sound very restrictive. Don’t be intimidated by those formulations. Of course everybody is always looking for the perfect match in a job offer. But if color blindness is your only disadvantage you might find your way through anyway.

Your 6 Steps

Recapitulating the facts listed above about regulations and job offers, you have to conclude that color blindness does really matter when you try to apply for an employment as a police officer. With a severe color blindness there is only a little chance to be employed. On the other side with a mild form of color vision deficiency, you might have some chances. Specially in the UK, where the regulations are the most liberal, you could make your way.

Let’s go back to our initial question, if you can become a police officer when suffering some type of color vision deficiency. As we learned, the answer is neither yes nor no. It’s something in between. And becaus you not just give up but keep trying hard to accomplish what you are aiming for, I list six steps you have to take to become a police officer despite your color blindness.

  1. First of all you have to check the severity of your color vision deficiency. This can be done either superficial with some online color blindness tests or thoroughly at your local eye specialist. If you suffer from a strong form like complete red-blindness, it will get quite tough for you to find a job as police officer. So this first step should help you to plumb your chances of success.
  2. After that you should try to find the eligibility notes of your chosen future employer concerning color vision. There are many different nuances in the regulations and they will give you some idea, what they demand. For example the LAPD is much more liberal than some other police departments.
  3. Before you apply you might ask, if color correcting lenses are applicable. There is a possibility of buying some lenses, which can help you to better distinguish certain colors. They don’t make you see more colors, but help to see some differences you can’t see without them. Some police departments might allow you to wear such color correcting lenses. Don’t hesitate to ask them.
  4. If you’ve taken the first hurdle of the employment process, you almost certainly will have to pass a color vision test. Take the test as good as you can without cheating. This will show them the truth about your color vision abilities and of course will be the basis for their decision making. If your application will be denied, try to find out the reason behind it. Maybe it’s not only your color blindness but also some other aspects. And if it is only because you’re colorblind, try to find out more about it; why they won’t employ you. This will help you to get a better understanding, if your type of color blindness is a barrier or not in your job life as a police officer.
  5. Failed the first time? Don’t be disappointed. You might try different police departments where you can apply as an officer. This will take you back to point #2 of this six steps list. And because regulations can be so different, there is most often a chance at another place to get the job you want. Only if you applied for more than one job you can say, that you did everything to make your dream become true.
  6. And if the first five steps didn’t help you to become a police officer, why not start with an other job in the police department and go on from there. There are not only police officers working at a police department. You might find another job you can start with and make your own way. If you are inside the system, usually some more opportunities will open up for you. So don’t hesitate to build your own personal career.

An to answer the starting question: YES, you can become a police officer even if you are suffering some form of color vision deficiency. BUT the way might not be the easiest one and it definitely won’t become true for some of you who are severely colorblind.

Random Color Scheme Syndrome

Did you ever hear of the random color scheme syndrome? Saucygrrl tries to explain what this is all about at Stop the madness.

She says, it’s something like color blindness, only that you are not colorblind but have a real bad taste when it comes to color matching. Free under the motto, everything fits well.

I would says, I definitely suffer under the random color scheme syndrome—at least when other people look at my color matching experiments.

But aren’t all you colorblind fellows suffering from it, are you?

Sunsets, Rainbows, Stop Signs for Colorblind Guys

John Trask is 76 years old and is Dealing with color-blindness is whole life. He says,

“I’ve never seen a sunset or a rainbow.”

Is it really possible that somebody can’t see a sunset or a rainbow because of his color blindness? – I can’t believe it.

SunsetWith not seeing a sunset he can only mean not to see the beautiful colorized sky and sun during a sunset. Seeing the sun going down behind the horizon can’t be a problem even for a colorblind person. And to my eyes also some beautiful colors can be perceived.

I’m red-blind, or at least strongly red-weak. And a sunset can be something really beautiful even to me. Of course, it will never be as colorful as for a person with normal color vision. But isn’t everything just less colorful for us colorblind guys?

RainbowAnd it’s the same for a rainbow. I can definitely see a rainbow—just less colorful.

A rainbow consists of the whole color spectrum and this with a blue sky or gray/white clouds in the background. So if you can’t see a rainbow, you must not be able to distinguish all colors either against blue or gray. And this could only be the case, if you suffer from a complete color blindness.

I don’t believe, that somebody with red-green color blindness can’t see a sunset or a rainbow. You can see them, but just less colorful as everything else on the world.

Stop SignBut what I agree on is another of John’s statements.

“Stop signs disappear,” Trask said. “The white lettering I can pick out, but [the rest of the sign] just fades into whatever is in the background.”

What are your experiences with sunsets, rainbows and stop signs?

Pictures by vtveen, Mundoo and overundulate.

Interview with Chris Rogers from COLOURlovers

Chris Rogers—also known as the lover named ruecian—is the man behind the site blog of COLOURlovers. I already reported about them, when they covered the topic of red-blindness just a bit more than one month ago.

Out of this first contact evolved the idea of an interview-exchange between the color blindness lovers from Colblindor and COLOURlovers.

As Chris is an expert on the topic of colors, in exchange he asked me some more details about color blindness, including positive and negative aspects of it. I hope you enjoy the following answers from Chris and make sure that you also visit the counterpart of this interview-exchange.

Colblindor: What is your favorite color and why?

Chris: I surround myself with blue because it’s such a daydreaming, imaginative nature. As someone who experiences synaesthesia, a sort of crossing of senses, blue is also the colour that has the best texture to me. With colours, I experience textures along with the visual aspect, and with music, I experience colours and textures. I like a lot of yellow, brown, and blue songs, so, I’ll say that those are my favourite colours.

Colblindor: COLOURlovers is a big resource concerning different aspects of colors. What are the main purposes of your website?

Chris: What I’ve come to find about COLOURlovers is that it’s sort of a playground for creativity, as the site has attracted colour-passionate and colour-oriented professions from fields of design and art. We also have people whom have said they would have never dreamed of playing with colour before stumbling about COLOURlovers, and have since become ‘colour addicts.’ I’d say we’re here to give an open, supportive space to the minds that want to come out and play, and I try to do that with my blog posts by posting something of interest, whether it be science or something inspirational.

Colblindor: Do you think color blindness might be some sort of handicap to join your community of lovers?

Chris: Oh, I don’t think so. Some of the palettes that users (colour-deficient or not) create might look a bit off, and the palettes that are based off of emotions might not convey the same message, but it all ends up meaning something to someone, as I feel colour and colour symbolism is loosely based in interpretation. Just as everyone feels differently about Picasso, everyone can find their own enjoyment in seeing a red palette, even if they don’t know it’s red.

Colblindor: You’re writing all about colors. When did it first come to your mind, that there is also a community of colorblind people and do you offer also some information, help or support for them?

Chris: I made a colour maybe what I guess to be about a year ago called ‘of Colourblindness,’ which was grey. And I remember having a note passed to me asking about colourblindness, and it was really my first venture in trying to explain it to someone. I had always understood the concept, but never had to put it into words. The idea had been in my mind since about that time, and surfaced soon after the blog began as the article that you found, which I wrote on Protanopia.

Colblindor: Do your users ever bring up the topic of color vision deficiency or is it almost not existing among lovers?

Chris: It has been asked before. There was a post on the forum about it, someone mentioned that they suffered from colour-deficiency, and needed some help pulling colours accurately from a painting. I do know that there are at least a few colour-deficient users on the site. It’s not a typical topic, though. I think hearing ‘COLOURlovers’ can be a subject of much fear for someone who can’t see colours like others can, but it’s really not about who does colour better, it’s about a love of colour, and I don’t think colour-deficient or colour-blind people are exempt from that.

Colblindor: Can you tell us something about the ‘headline’ of COLOURlovers “Fight for love in the colour revolution”?

Chris: As far as fighting for love, there is a rating system in place that ranks colours and palettes by how many votes they received and how many users have added them to their favourites lists. I think it’s also about how many comments are left, but I’m not sure about that one. I believe that COLOURlovers is changing minds about colour by bringing it to a field where anyone with hand-eye coordination can play, rather than having it restricted to artists with paint, or tailors with cloth. When I first stumbled upon the site in 2005, I was really cautious about my colour choices, and I created a lot of colours that were already in my life. The community is so very supportive. I’ve yet to see something negative said about something. In fact, I’ve even seen, “I love how ugly this is,” and it gets voted high. In getting used to COLOURlovers, I’ve essentially discovered a whole new world and my thought process as a synaesthete has been allowed externalisation. That’s what I think is meant by the ‘colour revolution.’

COLOURloversIf you enjoyed Chris answers, be sure to also check out his questions, published at the site blog of COLOURlovers. And if you enjoyed my questions, you might like to subscribe to the RSS feed of Colblindor, which ensures that you get frequently the latest updates and insights on color blindness.

How to Color Charts Respecting Color Blindness

If you are suffering some type of color vision deficiency you definitely know those situations: You try to read a beautifully colored chart, whereas the biggest challenge turns out to be matching the legend to the appropriate part inside the chart itself.

All the different type of charts usually have one thing in common, they have a color coded legend. This looks very nice and helps to differentiate between the labels and the information you want to highlight. But this doesn’t take into account, that colorblind people might have great difficulties to match the correct labels to their counterparts or even tell the different segments apart from each other.

Blue Yellow Graph
Blue Yellow Graph

Just recently the guys from evolgen asked A Question for the Colorblind, where they try to find good colors for some informative charts. The solutions vary between using only shades of gray and random color suggestions from non-colorblind people. I don’t think this is the right answer to the question on how to color a chart taking into account also colorblind readers.

Scott from Standardzilla tries to go a more elaborate way. He is looking for good color combinations and analyzes the color contrast as well as the simulations of different color vision deficiencies. Introducing his thoughs with Color Blindness and Graphs and analyzing it at Colour Contrast Chart for Colour Blindness.

I propose we even have to go one step further. Here is my recipe on how to color charts respecting color blindness in three steps:

  1. Start with the theory of color blindness. The confusion lines are a great resource to discover colors that are and aren’t distinguishable by all three types of color vision deficiency.
  2. After you have chosen some colors which are not on the confusion lines of neither protan nor deutan nor tritan defects, enhance the color contrast as much as possible, while adjusting the brightness of each color.
  3. Check the adjusted color combination with one of the many available color blindness simulation tools. If the simulated colors look to close to each other, start all over again.

This three simple steps are not as easy to follow as it sounds. I suppose it will consume quite some time to really find the best colors for your colored chart while having in mind, that also colorblind readers should be able to catch your information easily without spending to much time on color legend deciphering.

There are also some quicker ways to improve the readability of your charts:

  • Patterns: Not only use colors but also patterns to mark your charts.
  • Label Inside: If possible, label the charts inside themselves or…
  • Label Outside: …attach each label to its segment (e.g. around a pie chart).
  • 1 Color and Brightness: Use only one color and alter only its brightness.
  • Grayscale: And of course, you can use just different shades of gray.

If you either try to find some good colors for your chart which suite everybody—even the colorblind people among us—or if you take a quick-win doesn’t really matter. Just bear in mind, if you offer a chart with a bad color choice, one out of ten males might have problems with its readability, which doesn’t really help to get your point across.

Carnival of Colors IV – Strolling

This is already the fourth issue of Carnival of Colors. Please welcome the contributors and dive into the beautiful world of colors.

For the Carnival of Colors IV we have again some great submission which I would like to share with you. And be prepared for the next time, because for the first time Carnival of Colors will be hosted not by Colblindor but by the famous birdwatcher Mike Bergin from 10,000 Birds.


« While Irina was at a cafeteria she found this little nice garden. Strolling through it she took some really colorful pictures and realized, that she’s Surrounded by Beauty. This doesn’t really look like living dangerously to me does it? »

« You can see some more beautiful colors at Spring Days on the Riverbank. Riversider, the author of the Ribble Cycle Diaries, says “The predominant colour here is green”. It definitely is, but I can spot many more nice colors there. »

« To take some beautiful and colorful pictures you don’t have to go far. Christopher from Photographer’s Journey found the Colors of the Rainbow just around the corner. »

« Going round the corner and strolling pass a florist, don’t pick the red flowers for your beloved, because this are just Guy Colors. Doug knows more about it at Doug Green’s Garden, saying, “A politically incorrect but true story about garden flower colors.” »

« So you shouldn’t pick the red flowers but what about seeing red while you are collecting tokens. Alejna knows more about all the red folks out there. »

« I suppose Mike was strolling around almost a bit too long tonight. Watching maybe some late-night birds out of his 10,000 Birds. But anyway, it’s never to late to jump on the boat. And the birds which ‘Color me Rosy‘ just fit in nicely into this series. »

« Special entry by Suzan: Just read her story about the Blue Scratch and learn more about it, her and her blogstory at Behind the Politeness of It All. »

A great thanks to all the contributors. Stay tuned for the next release and join in whenever you have something to say about colors. You can find everything you have to know about the carnival at Carnival of Colors or just send me a note including the link to your article to be included in the next upcoming issue.