Last Call for Carnival of Colors III

Only four days to go until the next issue of Carnival of Colors will be published. If you are a blogger and have a recent article in some way related to colors, I would love to see you joining in.

This blog carnival is open to everybody. Every article not older than two months and in some way related to the broadly defined topic of colors is welcome.

This carnival gives you the opportunity to find others thinking, writing and painting with color and of course through your participation you open the doors for new visitors on your blog, who might like to even stay around and find out more about what you have to say.

If you would like to join, it’s never to late—only after publishing. You can either send me a note through my contact page, including the link to your article or submit your post through the Carnival of Colors homepage at

Previous releases of Carnival of Colors:

Don’t hesitate and join in for the next issue of Carnival of Colors. It will be published on the 1st of May 2007.

Colorblind Unaware Colorchoice

As I switched my domain to a few weeks ago, I lost my Google PageRank. While waiting for the next PageRank update I came across the LousigerBlick blog and had quite some problems deciphering it. This is definitely a good example of a colorblind unaware colorchoice.

Below you can see an actual screenshot of its design. Because of my almost red-blindness I have great difficulties in reading the normal text which is in a dark gray tone (is that right?). Links and titles which are white are no problem to distinguish from the background color, but when hovering over the links in a first glance they look like as if they would disappear as they are also turning gray.

LousigerBlick Blog

Before you release your design ask yourself if you did a color blindness check, used a colorblind web page filter or made a color contrast analysis. There are many tools available to check your choice of colors; don’t wait; do it now if you didn’t do it before.

Which Type of Red-Green Color Blindness is It?

To be colorblind is one thing. To know which type of color blindness you are suffering from is something different. Particularly red-green color blindness, the most common form of color vision deficiency, has several subtypes which are not easily distinguishable.

Yesterday I received the following question which I would like to quote here and hopefully give you some answers thereafter.

My husband is red-green colorblind, but we don’t know which type. What is the best way to go about finding out protanopia/protanomaly or deuteronopia/deuteranomaly? We’ve seen some of the test on the internet, but what do you recommend?

Maybe you are in the same position as the person described above; so let us dive in and find some answers for you.

Before I give you some advice on the how and why I would like to explain the technical terms above and set them into relation to red-green color blindness.

Red-green color blindness terminology

There are two different axis which you have to take into account. The first axis distinguishes if you have problems with your long (L) or medium (M) wavelength cones. The L-cones are red sensitive and are—if malfunctioning—the source of red-blindness (protanopia) and red-weakness (protanomaly).

On the other side are the M-cones, which are more sensitive to green colors. If your M-cones are absent or not working properly you are either green-blind (deuteranopia) or green-weak (deuteranomaly).

The other axis tells you about the severity of your color vision deficiency. Either you are a dichromat (protanopia/deuteranopia) and therefore you have only two different types of color receptors in your eyes. Or you have three different types of color sensitive cones, like somebody with normal vision, which is called anomalous trichromacy (protanomaly/deuteranomaly).

Finding out your subtype of color blindness

If you want to know for sure on which sides of the axis your color blindness sits, you have to go to a doctor for a check-up. But not just any doctor can do the job for you. Before your consultation you might like to check the following two points:

  1. Your doctor should be an eye specialist.
  2. He should have different possibilities to test for color blindness (check this in advance).

There are different color blindness tests available and every test has its advantages and weaknesses. If you put everything just on one test you might get a wrong conclusion. The list below gives you an impression of what tests could be available when taking your tests at an eye specialists place.

  • Pseudoisochromatic plates like the well known Ishihara plates tests.
  • Anomaloscope; Neitz-, Nagel- or also Heidelberg Multi-Color-Anomaloscope.
  • Lantern tests as the Farnsworth LT or the Holmes-Wright LT.
  • City University tests.
  • Arrangement test like the well known D-15 Farnsworth or the Farnsworth-Munsell test.

Every single test can play its part when you want to find out which subtype of color blindness affects you. Different tests together will give you an overall picture and a very good and reliable result when properly accomplished.

If you have your reasons not to go to an eye specialist you can try to do some color blindness tests by yourself. In that case you have to know, that these results will never be as reliable as when you consult your doctor. You also may not have the possibility to do many different tests like the ones listed above, as they are not publicly available.

There are many places where you can buy such tests like the Ishihara plates and accomplish the test at home. But this is usually way to expensive and as you are not trained in interpreting the results I don’t recommend it to you.

On the other side you can take some online color blindness tests. Before you head on, take your tests and think you know what subtype of color blindness is your one, let us step back and have a look at the difference between an online and a hardcopy test.

  1. Online tests are often scanned images. Because printed and display colors are very different and each scanner has its own color calibration, this images can look quite differently on screen. Therefore the results would not be the same and are less reliable.
  2. Every computer display is different. So if you take an online color blindness test using different displays the result could also vary.
  3. A computer display has a so called gamma correction. If contrast and brightness of your monitor or not very well adjusted this could also alter your test results.

Being aware of all that you can head on and try out some tests to find out more about your color vision deficiency. To get a more detailed analysis of your red-green color blindness I recommend you the three following steps.

  • Step 1: Take the Ishihara plates color blindness test and if this one is not enough check out the other source about Ishihara plates test. Through this pseudoisochromatic plates test you get an overall feeling of your color blindness but not a very accurate result.
  • Step 2: Take the color blindness test based on confusion lines. There are three different tests (protan/deutan/tritan) to choose from and when you write down your results you get a good understanding of which subtype of color blindness gives you the biggest problems.
  • Step 3: Take the D-15 Farnsworth Arrangement Test. These results will tell you more about the severity of your deficiency. If you have real problems accomplishing the D-15 test you are most likely a dichromat. Otherwise you supposably have a anomalous trichromacy.

Combining together the results of those color blindness test should give a more accurate knowledge about your color vision deficiency. Through step 2 you should be able to place yourself on the red-green axis. Either you are more on the red side (protanopia/protanomaly) or on the green side (deuteranopia/deuteranomaly). But be aware, if you have problems with one of those tests you will also have some problems with the other one, because the confusion lines of red- and green-blind or -weak persons are very close together.

Step 3 tells you more about the severity. If you are a dichromat and therefore have only two distinct types of color receptors in your eyes, you will have severe problems to accomplish the task arranging the colors in the right order. Otherwise you most likely have some weak form of color blindness. This shows you your position on the second axis.

Putting together step 2 and step 3 should give you a quite good overall impression of your color blindness. But as I said, there are many limitations to be taken into account and no online test will ever replace a consultation at the eye specialist.

I hope I could reveal some insights about red-green color blindness and help you to find out more about your color blindness in detail. If you did like this article you can either bookmark it with the button below or subscribe to my RSS feed to get fresh updates on color blindness.


COLOURloversThis guys call to fight for love in the colour revolution. Their weblog is all about colors and this means it is in some way a counterpart of Colblindor.

But yesterday they were really brave. They took a little trip into the world of color blindness and shared some information about Protanopia which is also called red-blindness (a subtype of red-green color blindness).

If you would like to learn more about the lovely world of colors visit their weblog called COLOURlovers. Their article about Protanopia can be found here. And if you like, you can even compare it with my own article about Protanopia (attention: self-advertisement :-).

Tone Deafness vs. Color Blindness

Musical Notes

Color-blind, tone-deaf or just
foto by Daily Dog

I am colorblind and fail every single test on color blindness. Maybe this sounds familiar to you; so let us have a look at some other -ness trait test which might give you a better feeling

Somebody suffering form tone deafness has problems in differentiating between distinct musical notes. In common language it’s also often referred to a person who has problems in reproducing a series of notes. Compared to colorblind people who might not be very much interested in colorful art or paintings, if you are tone-deaf you might not be the greatest fan of music or just sing when you are by yourself and know, nobody is listening to you.

Before you take the test checking your overall pitch perception ability be assured that color blindness is not in any way related to tone deafness. And now just relax, sit back, shut off your tv and your beloved radio station and test your musical skills.

I hope your results weren’t disappointing. Or if they were not that good I hope you at least perform well on the color blindness tests.

My results were 86.1% correct. A result I’m very much proud of because—you know—my color blindness test results look much worse.

Red Spring Blossoms

Yesterday my wife and I went past a plant in our garden. She told me about how she likes the red blossoms of it and only in this moment I realized, that this bush has blossoms at all.

Before yesterday I walked past a green bush day after day. Because of my color blindness (I’m very much red-blind) I never realized that during the last beautiful early summer days it had developed such nice blossoms.

Red Spring Blossoms

Red Spring Blossoms

Now I know about the blossoms and therefore I can see them. But still, they don’t catch my eye and seeing them through my colorblind eyes they are very well hidden inside the green leaves.

For me this is a very typical example how a colorblind sees the world different than somebody with normal color vision. But do you really miss something if you just can’t see it?

Deuteranopia – Red-Green Color Blindness

Deutan color vision deficiencies are by far the most common forms of color blindness. This subtype of red-green color blindness is found in about 6% of the male population, mostly in its mild form deuteranomaly.

Deuteranopia Color Spectrum

Normal and Deuteranopia Color Spectrum

When you have a look at the color spectrum of a deuteranopic person you can see that a variety of colors look different than in a normal color spectrum. Whereas red and green are the main problem colors, there are also for example some gray, purple and a greenish blue-green which can’t be distinguished very well.

The well known term red-green color blindness is actually split into two different subtypes. On one side persons which either lack or have anomalous long wavelength sensitive cones (protan color vision deficiency), which are more responsible for the red part of vision. And on the other side deutan color vision deficiencies, which again are split into two different types:

  1. Dichromats: Deuteranopia (also called green-blind). In this case the medium wavelength sensitive cones (green) are missing at all. A deuteranope can only distinguish 2 to 3 different hues, whereas somebody with normal vision sees 7 different hues.
  2. Anomalous Trichromats: Deuteranomaly (green-weak). This can be everything between almost normal color vision and deuteranopia. The green sensitive cones are not missing in this case, but the peak of sensitivity is moved towards the red sensitive cones.

Below you can see a picture with normal colors on the left side and altered colors on the right side. The picture on the right side shows you how a person affected by deuteranopia would see the scenery (picture taken by Ottmar Liebert, some rights reserverd).

Normal Vision Deuteranopic Vision
Normal Vision Deuteranopic Vision

In the midst of the last century there were different researches published concerning unilateral deuteranopia. Some persons were found which had trichromatic vision in one eye and dichromatic vision in the other. The eye with dichromatic vision had a color specturm related to a deuteranopia color spectrum. One case of such a one-eyed colorblind is described in the article The Spectral Luminosity Curves for a Dichromatic Eye and a Normal Eye in the Same Person.

The one-eyed color blindness is definitely not the common case, whereas deuteranopia and especially deuteranomaly are the most observed cases of all color vision deficiencies. In 75% of all occurrences of color blindness it is a defect caused by the green sensitive cones. The following list shows the approximative rates of deutan defects in our population:

  1. Deuteranomaly, Male Population: 5%
  2. Deuteranopia, Male Population: 1%
  3. Deuteranomaly, Female Population: 0.35%
  4. Deuteranopia, Female Population: 0.1%

These numbers don’t change much, because deutan color blindness as one form of red-green color blindness is a congenital disease. Red-green color blindness is a sex-linked trait and therefore encoded on the X chromosome. Because women have two X and can overcome the handicap of one, men have only one and are therefore more often affected. This circumstance can also be read in the numbers of the table above. More details about the concrete inheritance pattern can be found at The Biology behind Red-Green Color Blindness.

If you are colorblind there is a big chance that you are red-green colorblind, usually green-weak and male. And if you are suffering from deuteranomaly I just want to let you know, that you are nothing special…

Read more about Tritanopia and Protanopia—the other two types of color blindness.

Color Reading Cell Phone

Peter Jones, president of Tenebraex, is a really clever business man. He is making the headlines every few month with some new announcements. This time featured at cnet with the article Bringing color to the colorblind.

It was just about one year ago when the company was in the news with their software called eyePilot. This is a little software tool which helps colorblind people to distinguish and name colors on the computer. I reported about it in the Battle against color blindness with eyePilot and the follow-up post on RGB is not HSV.

Then again when school started last summer, they pushed their tool into some news channels and promoted it further. This time they focused at schools. EyePilot could help many children at school time to overcome their handicap of color blindness—at least in some cases.

Last time I heard about the company was November 2006 when I was contacted by Joanna L. Ossinger from the Wall Street Journal. She wrote an article about tools which help colorblind people and asked me for my opinion. Afterwards I had to ask myself if journalists have a work ethic, because after she got the information I never heard again a word and was mentioned by no word.

Color Reading Cell Phone

Color Reading Cell Phone

And here we are again. This time they neither have a new product to announce nor push their old one again. No, this time they just talk loudly about their ideas and are mainly looking for, well, money. Their new idea is a color reading cell phone.

This idea isn’t that new. The Color Luminator is a similar tool which was already developed by some smart students. Ok, it’s not a cell phone. But these days almost anything could be packed into a cell phone, if you only have a enough money.

From a business perspective, they definitely go the right way. I suppose they already made good money and will grow further with their well established tactics.

From a colorblind perspective it looks different. I did put together the following wish list for Tenebraex:

  1. Release eyePilot to the open source community. This way it could evolve to a nice little application which doesn’t just look like a fast hack with a big marketing machine behind it.
  2. Develop some great plugins for eyePilot. Those will enhance the product and make it a real nice helper tool for every colorblind person. With this strategy you could even earn some money.
  3. Then show us, that you really have something more to offer than just some ideas. Maybe you could get some help from the Color Luminator guys.
  4. After all that, approach cell phone companies and tell us, when you’re done.

If you follow this task list we will maybe soon have some great tools available for all among us affected by color blindness. Otherwise it might take some longer.

Is it a Wonderful World of Color?

A Great Big Nerd opens the curtain and tells us some stories about his life with color blindness. Very typical stories, which every colorblind among us knows by heart.

If you are colorblind, you know it, the same old question when someone learns about your color vision deficiency.

If you know a colorblind, it’s the first question you ask him (or in some uncommon cases her).

“What color is this?”

Do we really need to know? Our Nerd puts it this way:

Me: “There is our car, between those two blue cars.”
Em: “Where?”
Me: “Right there! Between the blue ones!”
Em: “Um, those cars are both green.”
Me: “Oh.”

So don’t be to pedantic. We are all living on the same Wonderful World of Color but just experience it differently.

Carnival of Colors II – Green

I would like to welcome everybody to the second edition of Carnival of Colors. This time we could double the entry count and have now four interesting topics to look at. If this carnival keeps growing at this rate, it could get really big—so stay tuned.

Last time we looked at the color Blue. This time we move on at the color circle to the color Green and have a look at it from very different perspectives.


« Green is the color that elicits relaxation. – This is the closing note of Deborah, known as Dr. Deb, in her contribution Want To Succeed? Don’t See Red. Luckily enough I am red-green colorblind and can’t really be distracted by neither. »

« Maureen presents Components Of A “Green” Home while she is looking forward into retirement and gets prepared for it. In her Empty Nest she moves the color Green into the environmental perspective. »

« You got me Mike. Color Me Fulvous could simply be renamed into Color Me Green because there is no difference to me between the yellow-brown color fulvous and green. That’s maybe why I will unfortunately never spot your 10,000 Birds. »

« After all this maybe Green is your choice of color? Karen writes about The Perception of Life; a perception which is not only black and white. Please, make your choice and Live The Power. »

Stay tuned for the next release of Carnival of Colors which will be released the first of next month. If you would like to contribute just contact me or visit the Carnival of Colors Blog Carnival Page.