Colorblind Policeman

When reading through Police Officer – Does Color Blindness Matter?, you could think that it is impossible to be a policeman when you are suffering from a color vision deficiency. But I was contacted by K., who told me a different story.

My life long dream has always been to work in law enforcement and about a year ago my life long dream was shot down when I found out that I was colorblind and couldn’t pass a color test. After doing some research on the net I found www.colormax.org and gave them a call. At first I spoke with one of their technicians who was able to give me a lot who was very helpful, I started to get very excited.

Could it really be possible to correct his color vision in a way to pass the required color blindness test? After a 20min phone call with the eye specialist he got really excited, because it looked like that there is a chance to get his dream job police officer.

About 2 months later I traveled to Baltimore. They got me the prefect lens for me to pass the color test. I had never worn contact lenses before, as my regular vision is perfect. Several weeks later I retook the color test, passed and was on my way in to law enforcement. My dream come true!

This story really sounds like a dream. But is it allowed to wear corrective contacts for a color vision test?

Before I went in for the test I put the contact lenses in my eyes. “Didn’t ask, Didn’t tell,” and I dont recall every seeing anything that said I couldn’t wear glasses or contacts for the test.

K. is now an unofficial colorblind police officer. I asked him a few more question which I would like to recapitulate in the following interesting points:

  • He can distinguish colors, but couldn’t pass the Ishihara test,
  • he is not wearing the color corrective contacts on his daily job,
  • and he doesn’t feel like his color blindness affects his job in any way.

Should law enforcement recruitment centers reconsider their viewpoint on colorblind police officers? Should everybody try to cheat on color blindness tests in a recruitment process? Or should you be upright and accept, that color blindness is most often a killer criterion to be a policeman?

Day of Links Two

Today I would like to share with you two links to other blog posts which are very much related to color blindness.

Gerald posted a picture on his Photoblog about Red Roofs and Colour Blindness and writes about his problems on color perception. Unfortunately with my red-blindness I can’t help him at all. It looks red, or brown, or anything in between.

The second link points you to a very interesting article: iPhone Available: Except To Color Blind Users written by Glenn. There was such huge a media coverage and I suppose many million people visiting apple in the last days. And apple offered a nice tool to check the availability of their iPhone. The only problem, it’s not made for somebody with red-green color vision deficiency. It is almost unbelievable that these days such big companies break the basic rules of accessibility.

Pretending Color Blindness – How to Uncover It

Usually people cheating on color blindness tests want to pretend, that they have normal color vision. This should give them the opportunity to get a job of their dream like police officer.

In this case it is just the other way around: Pretending to be colorblind to get the right job.

I am a doctor in railway and I have to do medical examination of the candidates for railway services. How can I determine whether a candidate having normal color vision is feigning/malingering of being color deficient.

Beside the question on how to uncover someone who tries to pretend color blindness, don’t you also ask yourself why somebody would do this? I had the same question. But first I will try to give an answer on the uncovering and afterwards I will tell you the reason for malingering of suffering from a color vision deficiency.

Uncover pretended color blindness

There are different possibilities how you can check if somebody is really colorblind or does only pretend it. They all are based on the same source: A non-colorblind can’t possibly know how a colorblind sees the world.

Usually you hear about red-green or blue-yellow color blindness and you could think, that’s easy to imitate. But it isn’t at all. This colors are just the main problem colors. For example I am red-blind and I have problems in distinguishing

  • dark-red from brown or very dark-green
  • orange from a grass-green
  • yellow from a very bright-green
  • but also blue-green from gray from some purple
  • any purples, violets, dark-blues
  • and when is something still very dark-blue and when is it black?

You can see from this list, it is not just red and green (red-blindness is a subtype of red-green color vision deficiency) but also many other colors. And by the way, I easily can distinguish some shades of green from some shades of red. And because of this, it is impossible to really simulate defective color vision.

Color blindness tests

Usually you will use some kind of color blindness to detect color vision deficiency. The most precise tool would be the anomaloscope to check for red-green color blindness. With this tool it is almost impossible to lie. You have to fit a combination of red and green to the brightness of yellow. Answers will always lie on a straight line. So if the match is just anywhere, the test person doesn’t tell the truth.

Using some kind of arrangement test with colored discs which have to be arranged in the correct order, makes it also almost impossible to cheat. The produced arrangement will follow certain patterns. Somebody with normal color vision can’t possibly find this patterns just by arranging them in any order.

Ishihara Plate 23
Ishihara Plate 23

The most common case would be, that you are using some type of pseudoisochromatic plates like the Ishihara color blindness test. They are based on numbers or signs made of many colored dots. And these numbers/signs are hidden to people with certain types of color blindness.

Now what can you do, if you are using pseudoisochromatic plates to uncover pretended color vision deficiency? Here are a few ideas, which you could try out:

  • Show the plates in a different order. Some may have learned just the correct order and know, what they have to see and what not. If you rearrange them, you can find out more about their real color vision.
  • Use the mixed plates. There are plates which include a number not visible to green-blind persons and a second number not visible to red-blind persons. If somebody wants to cheat on this, they really have to know what they can see and what not.
  • Include plates visible only to colorblind persons. Certain shades of color are only really distinguishable if you are colorblind. So if you add some of those plates it will be hard for someone pretending to be colorblind.
  • Don’t use the Ishihara plates. The Ishihara color blindness test plates either containing 24 or 26 pictures are very well known. A candidate could learn them in advance. If you use some other pseudoisochromatic test they will struggle.
  • Mix in some of your own plates. Maybe you have the possibility to make some of your own plates with a program like Photoshop. For instance you could make some with no hidden signs and tell the person under test, that these plates have a sign which can only be seen if you are colorblind. How will they react? A person which is really colorblind, will tell your right away that he can’t see anything.

Other strategies

As I mentioned above, a non-colorblind will never know how it is to be colorblind and which colors can be distinguished and which not. Here are a few more ideas apart from the color blindness test above, which could help you.

  • Make a vision test including red letters among black ones. Ask the person under test to read the red letters. A colorblind person usually can’t easily spot red letters mixed in into black.
  • Let the person name colors. Somebody with color blindness will have problems in the whole range and mix up very typical colors. Someone with normal color vision will have problems to fake a bad color perception.
  • Ask them about everyday problems caused by their color blindness. Problems are for example skin color (has somebody a sun burn or is he sick?), cooking meat (when is it readily cooked?), LED lights (is it green, red, orange or yellow?), color charts and more.
  • Does the person have problems with traffic lights? I mean they are red and green, aren’t they. Usually this doesn’t cause real problems to somebody with a color vision deficiency. But does somebody who just pretends to be colorblind know about this?

You might try these strategies first with a few test persons—colorblind and not colorblind. This will make sure, that you have chosen the correct problem colors and situations.

Why should someone simulate color blindness?

When I received this reader question I of course asked myself, why somebody should pretend to be colorblind? What can you profit from this?

The candidates for employment in Indian railways are selected in seven different categories.These are A1,A2,A3,B1,B2,C1,C2. Employees of Category A1 to B1 are safety category staff who are required to have normal color vision while those of Category B2 to C2 don’t need to have normal color vision.

Many posts like that of booking clerk, parcel clerk, train ticket examiner etc. come in Category B2 and these are quite lucrative posts every new candidate wants to get, since they can generate extra income by corrupt practices.

Those candidates who are sent for medical examination in category A1-B1 often malinger as if they are color deficient so that they may be disqualified for the posts in A1-B1 and can get fitness for category B2.

Very interesting. Thank you very much for asking this question and sharing this insights with us. If you have your own question concerning color blindness, don’t hesitate to ask me.

Love the Colorblind

I Heart Color
I ♥ Color

The Fuck the Colorblind t-shirt seems to be very popular. A lot of people are looking for it and I received quite some comments on it. Some people like it, others not.

Here is the counterpart: I ♥ Color. Well, I know. It’s not really saying anything about colorblind people. But it is also made out of a pseudoisochromatic picture, also known as Ishihara plates. This texts or numbers usually are hidden if you suffer some type of color blindness.

Can you see it?

The shirt is available at Threadless T-Shirts. And there are some nice pictures of happy people wearing it.

Now it’s up. You can decide between Love the Colorblind and Fuck the Colorblind. Which message do you prefer to put on your chest?

Carnival of Colors V: In the Eye of the Beholder

Mike from 10,000 Birds put together a fantastic issue of Carnival of Colors. His introduction into the submission list of eight great articles about color, reads as follows: “Color, like beauty, is in the eye of the beholder.”

Make sure to visit Carnival of Colors V. And put a mark on your calender on the 1st of august. This will be the next release date of Carnival of Colors. Contributions are very welcome and if you would like to host one of the future issues, just let me know.

Colorblind Men Suffer under LED Lights

I’ve got a laptop and I’m writing this story down on it right now. It has three little LED lights shining steadily and one blinking on an USB device. But which color are they?

A lot of LED lights are used to show you different states of just anything. Either its on or off, connected or not, loaded or empty, working or on hold, not loading or loading, and more. Right now I can think of several devices in my household which have LED lights on them to show me just anything and everything: stereo, router, electrical toothbrush, electrical razor, sawing machine, digital camera and of course my laptop.

Red and Green LED
Red and Green LED by Sebastian Yepes

All of those LEDs want to tell me something, but I can’t see it. Due to my color blindness I just don’t see the difference between those green, red, orange and yellow shades. I can distinguish the blue ones from all the colors above, but this combination is unfortunately not often used.

Have a look at this very nice picture taken by Sebastian Yepes F. He says that this picture is made by a red and a green LED light. I can’t see them.

I mean, I can see the colored circles, but aren’t they in some shades of orange, or maybe yellow, or—oh I don’t know.

LED Rainbow
LED Rainbow by Andrew Hoyer

Or this nice rainbow taken by Andrew Hoyer. Shall I listen the colors I can see: red (or brown?), red (or orange or what?), green (or yellow or still orange), then brighter blue, blue, darker blue.

I definitely like the first three. Unfortunately this are the ones most often used inside electrical devices—which are not designed for the colorblind.

So dear manufacturers of things including LED lights which should tell me something: Please either use blue combined with yellow, which should be differentiable by everyone, or use blinking and non blinking LED lights. Colorblind persons have huge problems with all those little lights in green, yellow, orange and red. And as there are up to 10% of all men colorblind, this is definitely something to think about.

By the way, I never know it the batteries are loaded on my laptop or not just by looking at the battery LED. I either just plug it long enough or ask my not colorblind wife :-)

Stroop Test – Can You Read the Colors?

In case you’re not colorblind, naming a color is an easy thing. But naming a color if it is a colored word of another color name (e.g. green) is definitely not that easy to accomplish.

Stroop Test
Stroop Test

The Stroop Test was described by John Ridley Stroop back in 1935. He took some color names and just colored them differently. Try it out yourself with the graphics below. Don’t read the words but say aloud the color names you see.

Did you do well? Even if you have normal color vision, after the first two lines you start struggling because the wrong names are very distracting. And how did you perform, if you have some type of color blindness?

For me it looks interesting and I can see some differences in the colors. But it’s definitely just a guessing game. Colors I can almost not distinguish and therefore have big problems to name them in this graphics are:

  • BluePurple
  • OrangeGreen

Do you know, what I like the most about this? It’s the color Red I can spot easily, despite the fact I’m red-blind…

Colors in Your Life

Which are the most powerful colors in your life? Do you have any at all or are they changing from time to time?

Tell your story and join the next issue of Carnival of Colors. This carnival includes anything in anyway related to colors. So don’t wait and write your point of view concerning this broad topic.

My favorite colors are a grass green and a sunflower yellow. I also enjoy blood red or a very dark tree-leaf green.

The next issue of the carnival will be published first of July. This time the carnival host is Mike from 10,000 Birds. Thanks Mike and a warm welcome to all the friends of birds in the world of color blindness.

If you like to join, just contact me including the link to the article you wish to be included.

Day of Links

Today I found two links I would like to share with you:

The first one is from Chris, the writer behind Mixing Memory. He had a closer look at the Color Opponency in Synaesthesia. People with Synaesthesia perceive colors even when looking at black letters and numbers. Some researchers discovered now, that if you show such persons wrongly colored color-names (e.g. red) they have very different reaction times than people with no Synaesthesia.

The second link is for web publishers. Skye claims that you have to Check Your Link Colors – You May Need to Redecorate! This is not only true for professional web designers but also for any blogger running a free blog software. If you are interested in accessibility you might enjoy her weblog about all access blogging .

Monitor Simulates Colorblind Vision

There are many tools available, on- and offline, which show you how a web page or image is seen with a color vision deficiency. These software tools are great and should be used by every web developer.

FlexScan S2411W
FlexScan S2411W with Color
Vision Deficiency Simulation Capabilities

Eizo went even one step further and introduced this simulations into some of their LCD monitors as a hardware solution. This gives you a realtime transition, which doesn’t need any CPU time and is working even with fast moving movies.

They introduced two different simulations: One for red-blind persons (protanopia) and the other mode is used to simulate green-blindness (deuteranopia).

Protanopia and Deuteranopia Simulation in Real Time

Simulates two types of red-green color vision deficiency – protanopia and deuteranopia. The FlexScan S2411W does all the color conversion processing in real time – even moving images. With the bundled UniColor Pro software (Windows Vista/XP/2000 and Mac OS X 10.3.9 or later only) – also developed by EIZO – the designer can instantly switch from a normal viewing mode to the Protanopia and Deuteranopia viewing modes.

Up to now the system is implemented in the models FlexScan S2411W, FlexScan L797-U, and ColorEdge CG241W.

It would be nice to see one of those monitors with the color conversion processing in action. Especially a comparison to some good software simulation tools could be very interesting and show if Eizo can really deliver what they promise.