seeing the ultraviolet

[Butters]

At the extremes of the visible spectrum there’s UV and infrared light that we can’t see. With the right equipment we can see images constructed from this light, but that’s a false colour image.

What would it be like if our visual range was extended slightly to incorporate these? Seeing both the regular colours, and also heat. How would we perceive that? Seeing the difference between a hot meal and a cold one, just by looking at it.

Would it be interpreted by the brain as an extra depth to regular colours we see. When the sun goes down, still seeing people.

In sci-fi, when we see infra red vision, it’s always infra red camera, but how different would it be overlaid the regular light.

I can’t visualise it. Be interested to hear other’s thoughts.

 

[Steven P Bastien]

We would need additional color receptors to see other colors. If you see real infrared at the very edge of your perception (not through a scope or camera), it appears to be a very deep red because only the red cones are activated significantly and the green and blue cones are not. One has to remember that all three cones have some response over the whole range of visible spectrum and it is the ratio of RGB that our brain interprets as the specific color. Once, the light is into the infrared or ultraviolet, then it appears as deep red or deep violet, respectively. Eventually, the response falls off so much that we dont see color, but the rods might still pick up some faint response that appears black and white, but the rods do not respond well to infrared.

It's not possible for us to imagine other colors.

 

[Butters]

It’s the imagining of other colours that I’m trying to do.

So something hot, emitting heat, would appear to us as deep red, but if the hot thing was also painted blue, would it just appear as a reddish blue?

 

[Steven P Bastien]

It depends on how hot. All bodies have black body radiation. At room temperature the radiation is in the far infrared and you can't see that, you can only feel it. If it is painted blue it will appear blue. But if it gets hot enough, the black body radiation will move to higher frequency and eventually become visible. -first red then yellow, maybe white and then eventually blue and even into the ultraviolet (which you might not see) if it gets hot enough. But, if that hot, it probably already melted and evaporated.

 

[TrickyDickie]

Sky-blue pink:

http://www.worldwidewords.org/qa/qa-sky1.htm

 

[JirinPanthosa]

First, cameras that view body heat do so the same way that we view the sun. They just see longer wavelengths.

Trying to imagine four colors is like trying to imagine four dimensional space. We just don't have the hardware, and any real model of it in our brains is just going to be 3d projections.

There are animals however with more types of cones.

 

[Asbo Zaprudder]

Ask a Mantis shrimp. Depending on species, they have between 12 and 16 types of photoreceptor cells compared to our usual four (rods and cones). Some people have an additional type of cone cell that supposedly gives them enhanced colour vision but it won't allow them to see in UV - the physical composition of our lenses blocks those wavelengths. By the way, it's impossible to know if any two people see a colour in the same way. Such qualia are beyond description - try describing the colour blue for example. You can point at an object and agree that its colour (and associated wavelength) is a perceptible quality that you label as "blue" but that's it.

 

[YellowSubmarine]

False colour images are a correct interpretation (one of the many possible) of how a regular trichromat would see an extended colour spectrum. That's exactly how you'd see UV or IR if you could (well, one of the exact ways anyways). What's more fascinating is how a tetrachromat would see in any spectrum. (Nature blog on tetrachromacy).

6% of men and 12% of women carry an anomalous colour gene (OPN1MW2 instead of OPN1MW1) in their X chromosome, causing them to see a slightly different red/green (the anomalous gene also seems to be responsible for one form of colour-blindness). Most of these 12% of women carry both genes, with estimated 2-3% having four cone cells in their eyes instead of three. After 20 years of study, one woman was identified to be able to see four-dimensional colours. There's also artist Concetta Antico who claims to be a tetrachromah herself. And Jay Neitz, the doctor who reportedly discovered her tetrachromacy, claims it's possible to use gene therapy to cure not only colour-blindness, but trichromacy that 99% of us suffer from, restoring us all to proper 4-cone sight.

So, all you have to do is find a tetrachromat near you, show them a false colour image in 4 colour dimensions of an UV or IR photograph, and ask them. Or subject yourself to dangerous experimental gene treatment, like those crazy CRISPR biohackers, to become a functional tetrachromat. (In case you take this sentence seriously, DON'T DO THAT. What these people are doing is DANGEROUS.)

Alternatively:

There are lenses/lenses for people with dichromatic vision that pass the additional colour to the non-dominant eye (those are different from the glasses/lenses seen in viral videos that filter wavelengths for people with cone anomalies, but don't work for dichromacy).

You could potentially build such glasses for trichromats instead of dichromats to see a fourth colour. If it's only for a certain IR/UV photograph you don't need to design expensive hardware, you just need to hack a ‘video’ for your 3D TV that shows one false colour image with one extra colour to your non-dominant eye, and the regular colour image to your dominant eye. (This type of glasses don't work very well, though; and neither will the TV hack.)

tl;dr: If you just want to see a colour you've never seen before using a similar two-eye effect, just open this image, and try crossing on one of the two pictures, so that the red and green overlap in the middle of your vision; or that blue and yellow overlap. You see two colours you've never seen before. (It helps if you move your head closer to the monitor.)

 

[Jedman67]

it would probably look a greenish-purplish