How do colorblind people view rainbows?

Would a person who is severely colorblind see different shades of grey, or nothing, or something else?

this gives various examples of what colorblind people see. The most common form is red-green where red looks like green.

What I am talking about according to your cite is “monochromacy”, not “red-green”. Are there any examples available as to how a rainbow would be viewed?

It’d still be light.

Red objects reflect a fair amount of green and yellow light; green objects reflect a fair amount of red and yellow. This is why Enchroma glasses work, I think: they filter out the yellowish hues that impact red-green discrimination.

But a rainbow divides sunlight into spectral colors. Thus I would expect people with red-green discrimination difficulty to be able to perceive the colors in the rainbow. (Of course this depends on how crisp the rainbow’s spectralization is.)

Enchroma glasses are suspect. They are just different colored lens for each eye that make red and green appear a little different. It’s nothing new, it’s been done before, Enchroma is just hyping their product.

I don’t know the biology behind monochromacy, but assuming that the luminance detectors in the eye have different spectral sensitivities, and the luminance of the different colors of the rainbow are different, there’s a good chance that the bands would be distinguishable. But, it’s likely to be a slight difference.

You won’t actually see pure monochromatic light by looking at any spot on a rainbow. You can think of a rainbow as being made up of a band of 700 nm light, and a band of 699 nm light, and a band of 698, and so on covering the entire visible spectrum down to 400 nm (and beyond, but who cares about the invisible colors). But those bands have a nonzero width, at least half a degree (the angular size of the Sun), and probably more, because the optics of a rainbow causes further spreading even from a point source. So any given spot on the bow will include light from a whole range of colored bands.

Yes, like this. The contrast between the rainbow and the surrounding sky is still visible even without the colors.

The rainbow doesn’t divide anything, it’s a continuous gradient that gets made discrete by human perception.

Cite? Everything I know suggests the lenses are both the same, they just multi notch filter the light.

The most common cause of monochromatic vision is brain injury e.g. stroke. In that case the retina is usually fine but color doesn’t work properly in the visual cortex. It can also be caused by retinal dysfunction, but that is rare as it (usually) needs two separate genetic problems that are already rare themselves.

According to Enchroma you are correct, I received some poor info, or maybe misinterpreted it. But numerous reports indicate less success than they tout. Perhaps they should combine the techniques. I know a pilot who used different colored contact lenses to get through a color vision test. He told me the colors red and green just looked funny in different ways, good enough to distinguish them. What Enchroma does sounds like it would be even less successful for most people.

I’ve not heard this before and would have suspected optic neuritis as the most common cause of loss of color vision. In fact, I’ve seen lots of stroke patients and don’t recall this as a manifestation. Maybe I never asked. No snark, but can you refer me to a cite?

Just one example, but maybe I overstated it, talking about congenital/genetic vs. any acquired cause. TBI is a little idiosyncratic to get a real prevalence rate among a population. I guess a better point would be that retinal monochromacy is much rarer than single-cone colorblindness.

Have a look at this video. They don’t show a rainbow, but the images of colored pencils they show as perceived with different types of “color blindness” illustrates how colors in the rainbow would be perceived:

This page has several other examples, including nyam cat with its rainbow contrail and a photo of a rainbow:

I am red-green colour blind.

The rainbow is murky yellow and dark blue.

That pretty much agrees with the image of the rainbow in my second link above. (labeled “Protanopia”, Red-Green colorblind)

I see all the major colors, just very less intense red and greens. At a distance they can look the same muddy brown.

Thanks to Nars Glinley of this message board I got a chance to try out the enchroma glasses that let me see what normal vision looks like. I now get why people croon over autumn foliage. I get it now. Didn’t before.

Question for (red-green) color-blind people:

Are laser-produced red light and laser-produced green light easily distinguished? (If not, then I’m apparently confused both about color-blindness and about Enchroma glasses.)

For me, yes pretty easy to distinguish.

I see a rainbow. with different colors. And I just found out last month our living room is a very light pink not a light blue green.