How do colorblind people know colors? And what's up with purple?

So, I felt the need to cry like a hormonal teenaged girl and was watching people getting enchroma glasses and seeing color for the first time. In many of the videos there was a thing with a bunch of colors-- balloons, streamers, paint color swatches-- and the person was asked to name them. And they did. How’d they know if they never saw it before? The one young boy named all the colors of the balloons in front of him. When his dad asked what he saw without the glasses, the little boy said all the balloons were the same, except for the red balloon, which looked “brownish”.

Also, if something was strongly purple or violet, a lot of them had a very strong reaction to it. One guy was frightened by the color purple and literally ran away from a box of cleaner, he was so afraid. Many of them say, “Purple? WOW!” like the boy in the previous paragraph.

So. . . how do colorblind people know colors and why does purple cause such a strong reaction?

Ooops. Wrong forum!

I’m not sure what you’re asking exactly, but I have common red-green color blindness and I see colors just fine, just not the same way you do, probably.

There are many different types of colorblindness, only one of which is full monochromacy (achromatopsia) and it’s quite rare. Most colorblindness is characterized by a “confusion” of colors, e.g. red and green are indistinguishable from each other in certain, if not most, conditions.

Here is a convenient explanation of the different types of colorblindness.


Moved from CS to GQ.

It’s very rare for someone to be completely colorblind, and for those who are I don’t think special glasses would help. (At least not with current technology.)

A quick Google turned up this Atlantic piece about EnChroma glasses by a writer with red-green colorblindness who tried them out:

I have deuteranopia (“green-blind”) myself, so there’s quite a lot of mix-up going on with my color perception. It’s not that I don’t know what specific colors are supposed to look like, it’s just that when a bunch of certain colors are physically close together, I either can’t see or it takes a concerted effort to distinguish the difference between them.

There’s the little girl!

I don’t know about the purplophobia, but there are several sites avilable to show you (more or less) what people with various types of colorblindness see. For instance, this one.

After watching a few more, some people do not know the names of colors. But purple leaves a large impression on almost all of them.

Thanks for the links, guys. Very informative.

From the article Lamia linked to:

I think that may explain a lot. But man, purple! As one guy with Enchroma glasses on said as he cradled the purple gladiolas he purchased, “I can see why it’s the color of royalty.”

But colors are a lot more than what happens in cones. They’re not facts reported from our retinas; they’re thoughts, created in our brains, incorporating the signals moving upstream from our eyes with other information from memory, expectation, and context. Exactly how this disparate data is combined to make a single cohesive experience of color is a great ongoing mystery.

I think Land, in his “retinex theory” experiments was the first to demonstrate that color perception is not locked to the wavelength of the light entering the eye. Any given wavelength can be perceived as many different colors depending on other things in the visual field. In other words, color isn’t as much a perception as a decision.

Old threads on this.

The gist is that Enchroma overstates things, and most colorblind people find it cool but not life-changing.

The types of color blindness these are intended to target generally don’t have any problems seeing purple (or violet), so it’s hard to say why these people might react this way.

It’s the color of royalty because the dye was expensive to synthesize and the hoi polloi couldn’t afford it, buddy.

Taken from the web

Its also one of my favorite colors!

Australian surf photographer Ray Collins is colorblind. He talks about it in the short video at the end of the linked article.

Some of his work has been turned into cinemagraphs by Dutch cinematographer Armand Dijcks. They are animated stills created using Adobe After Effects. But each is just a single shot.

Purple is made up of red and blue, and the red part is lower. My guess is the amplifying the red allows them to see purple as different from blue for the first time.

My understanding of the glasses is that they filter out the wavelengths that are the hardest to distinguish. Since most hues in nature are actually a mixture of similar wavelengths, this actually results in making colors easier to distinguish.

I actually found a survey where colorblind people most often reported purple as a color they couldn’t see at all, over all other colors. Color Vision and the Efficacy of EnChroma Glasses | Dr. Blake Porter

I have Tritanomaly, weak blue reception. I first realized this about 10 years ago seeing an online test card, but only last year had it verified by an ophthalmologist with real test cards. It’s mild, I can see blue but it’s not very distinctive, any blue green mix looks like green to me. I can recognize purple but it may not be as distinctive for me. The simulator from post #8 doesn’t change much if i switch from normal to tritanomaly, I can tell the purple thing on the left is different, but not that much.

After discovering this I told my mother about because of our old disagreement about the color of some plastic dishes. At this time, after 50 years or so, she decides to tell me father had some kind of color blindness. She doesn’t even know what it was, she thinks he couldn’t see green, but it’s too late to ask him now.

I did meet a pilot with common red-green colorblindness who said he was able to use special contact lenses to be able to pass vision tests. These were simple red and green lenses that made these colors look different to each eye, not that they magically enable color vision.

Yes, the blue-purples are almost indistinguishable from blue. I sometimes guess them correctly but I guess based upon the deep hue.

However, magenta, burgundy, wine, are easy to see - they must have a stronger red component. However if they are too deep in hue they look brown.

I have gotten into some fairly serious arguments with some people about whether something was purple or blue (my high school colors were purple and gold so it came up frequently). Those things get surprisingly heated because I thought they were being deliberately obtuse but now I realize that they probably have some version of color blindness. I have taken the official tests myself and can differentiate all colors down to finest levels testable but I know now that not everyone can do that.

I think aids like Enchroma are interesting but they bring the old marijuana fueled philosophical argument of “I see colors but are they the same colors that you see?” full circle. Well no, they aren’t at least for a significant percentage of people. Even with aids like that, people may be able to differentiate colors that they couldn’t before but they still almost certainly aren’t the same colors that people with normal color vision see.

There is also a lot of variation on where people place the blue/purple divide, without anything that’s bad enough to cause problems, and thus is characterized as a harmless variation rather than any sort of disorder.

I know that, when I lighten some colors (on my computer) that I think look blue, I get colors I think look more purple, and thus always change the hue a bit to make it more blue looking to me. Technically, I’m pushing it more towards cyan. What we call light blue is often more cyan in hue.

Also, monitors are weird. I see the background of the Straight Dope logo as being blue-violet on this computer, but I saw it as just dark blue (the same color as unclicked links) on a different monitor.