Colorblindness: OK, girlfriend, maybe you should sit down.

A girl; and the girl as seen by a guy with Deuteranopia.

by Michael F. McNulty

Whether we’re happy about it or not, we all know what we look like — if we can see at all. And we tend to assume that others see us the same way we see ourselves. But then, we also know that some men are colorblind. The actual number is about ten percent (and less than one of one percent of women.)

That’s fifteen million American men. How often do you consider how those men see the world? Never: right? Or, if you have a significant other, maybe you’ve held up something you find beautiful and colorful and have asked “What color does this look like to you?” And he has stammered and tried to change the subject.

Take it a step farther: how often do you consider how they see you? I know: less than never.

There’s a pretty obvious reason why we don’t go down that road. Like, who knows what they see?? Generally, they are really, really bad at explaining the colors they see. But that’s not their fault! How are they supposed to put words to things they cannot see? It is really not fair at all to expect them to spell it out.

But there’s good news: technology is catching up to this conundrum. It is clear that it falls to us, the color-sighted, to take responsibility for bridging the gap. How about some insights, and maybe a dollop of science!?! This will be more fun than you expect.

Color blindness nearly always means that the red in your visual field is fakakte — not that there’s anything wrong with that.

First, let’s get this out of the way: colorblindness does not mean that you’re blind to all colors. That would mean you can only see in black and white. That’s a 1 in 100,000 occurrence.

They (and by ‘they’ I mean those who have Deuteranopia, the most common form of color blindness) can usually see yellow, blue and purple. Pink can seem sky blue under bright light. And as for red and green, they’re indistinguishable, and mostly colorless. Orange doesn’t fare any better.

Taking this set of parameters, and applying it to the way we ‘look’, the big take away is this: if you pull red and orange out of an image, human skin doesn’t fare so well. But we needn’t leap to the conclusion that colorblind men find all women sallow, ghoulish, or zombie wannabees. If you grew up colorblind, you’ve never seen pink skin, and you learn a separate set of visual clues about healthy skin based upon different visual cues.

This condition results from being a dichromat (‘di’: two; ‘chromat’: color). Would you believe that this view of the world is not rare at all? That it’s common? Nearly every mammal in the world is a dichromat. Lions and tigers and bears? Dichromats. Pandas and jaguars and wolves? Dichromats. So let’s set something straight right now: if the most fearsome predators in existence have made their way successfully through the world for millions of years, then being a dichromat is not a discernable handicap!

Only humans (90% of us) and the higher apes are fully functioning ‘trichromats’, privileged to see all the colors in the rainbow. Because the gene for colorblindness are stored on the X chromosome, women rarely see a problem, so to speak, because they have two X chromosomes. If they lack one gene for trichromacy, the other steps in to fix things. But men, having the notorious XY chromosomes, sometimes inherit a defective ‘X’ from their mothers. Color blindness is passed down, mother to son.

Of the 8+% of men and ½% of women who have some level of colorblindness less than half have the full-on red/green colorblindness that is reflected in these side-by-side portraits. The majority have degrees of color blindness than is less severe. (N.B.: We’re supposed to slowly migrate to the term CVD, for color vision deficiency — since color blindness is simply an incorrect label.)

It has long been the case that getting a precise fix on the level of one’s affliction (or, “differently-abled vision”?) could be a medically expensive proposition. But now there are a nifty on-line tools that will clarify how accurate your own vision is, or confirm the sort of colorblindness someone close to you may have. A good example is a highly recommended app, presently in Android, only — And it’s free, natch’. It springs from a wonderful website called Colblindor, which is a labor of love a Swiss father named Daniel Flück. Do further research, there.

Deuteranopia — Full Color — Protanopia

So how does color blindness affect the way we’re seen? Here’s a side-by-side comparison of the two most common color deficiency diagnoses: on the left, the view seen by those with Deuteranopia, and on the right, by the view seen by those with Protanopia. The similarities are obvious: whites are still white; tonalities (lights and darks) are the same; the color blue is mostly constant. And the differences between the two red/green colorblind diagnoses are mostly too subtle to bother with.

With Protanopia, blue is stronger. Colors that are blue mixed with red (like purple or lavender or violet) just become blue. Yellow becomes nearly white. Pink flowers reflecting both blue and red light become just blue.

With Deuteranopia, there is a slightly greater perception of yellow. Thus reds and oranges become a muddy brown. And greens become a shade of peach. Violet becomes nearly black.

As these photos illustrate, many “red” lipsticks — upon further examination — turn out to be red mixed with other colors. If those other colors are blue, then red turns to blue. If the red is mixed with orange or lime or any other color that colorblind people cannot see, then the color simply disappears. But the ‘luminance’ does not change much at all: that is, the brightness or darkness of the color.

Most varieties of color blindness still allow one to see blue.

Since color blindness is genetic, its presence differs markedly between different human populations. The Navajo, aborigines, and (very curiously) Mexicans have overall rates of colorblindness of less than two percent. The Dutch, members of the Druze community in the Middle East, and Norwegians all have rates approaching ten percent.

There’s a gulf of misunderstanding about colorblindness the size of the Grand Canyon, and it’s magnified by the distinctly American stubbornness to meet people half way. We not only don’t quite get it, we don’t want to get it. We don’t want to be bothered. If you have a problem, deal with it!

That’s a mistake. In Europe, they’ve been figuring this out. In every little bureaucratic outpost in the European Union, if you want a permit to put up a sign you must submit with your paperwork a version of your sign that shows how it will be seen by people who are colorblind. In the U.S.? Ha. You can’t see red? Well you’d better figure out a work-around because we’re not changing our stop signs for nobody. We’re not going to mollycoddle those who can’t see red, even if there are fifteen million Americans who are dichromats.

And we’re still not going to do anything even if, by doing so, the rest of us would be much safer.

is easy to wonder why red turns to blue for someone with Protanopia. The answer is that the lipstick and the eyeshadow in the left image are not red. Or at least not pure red. All manner of colors are added to red to make it a more interesting color. Just visit a couple cosmetics stores if you want to see thousands of shades of not-really-all-red.


If you’d like to see how you (or anything else) looks to someone who’s colorblind, try this useful tool: You can upload a photo of yourself, and review how it looks under seven different color deficiency scenarios.

On the left, full color; on the right, the same image as seen by someone with Deuteranopia.

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