Are there colors that do not occur naturally?

Don’t know if it’s related but this question reminded of this short question.

all colors all achievable thru manipulation of the standard ROY G BIV rainbow colors…thus can be found somewhere in nature even in some of the most obscure place

Pigment is a subtractive process, color is an additive process. No unnatural color can occur; that is a nonsense statement. If it occurs, it is natural. The question is, does color occur at all? It is a perceptual phenomenon that takes place only in your brain, and as such it is a sort of hallucination. It is not a property of any object.

Building on @pdworkin ‘s post, the colors that synesthetes experience don’t arise through the usual channels of visual processing, but are produced by cross-activation in the fusiform gyrus of the brain, skipping some of the preliminary stages of processing. Typically these colors are conventional colors, but some synesthetes report colors that don’t correspond to anything produced by normal visual stimuli.

I don’t believe there are any colours that don’t turn up somewhere in nature, it could be a fun project to line up all the spectrum using pictures of plants or animals.

Sometimes I try to imagine a new colour… I usually find it quite impossible

Does Harp’s brain occur naturally? Or is it a nine-wonder? (Oops. I am forgetting Jayne’s brain – equally impressive. It must be a mutated gene.)

@pdworkin ,@Harp, Let me clarify what I meant. When I talk about naturally occurring I mean that the color is the color of something that can be seen in nature.

Color is a reflected light, so to get a color that doesn’t exist in nature, you’d have to get a light that doesn’t exist in nature.

Wait… Is that right? I have no idea what’s goin’ on.

Human perception of colors isn’t a simple mapping of wavelength of photons picked up by the eye to a corresponding color. Interesting stuff goes on in the brain (I myself don’t remember the details), some of it can be tricked by various setups to cause optical illusions. On the other hand, it isn’t so independent of the nature of objects that we observe that I would go so far as to call it hallucination (Richard Feynman was quite vehement on this point in one of his famous lectures on the theory of light). Color vision is a legacy of our adaptation to help us survive in the natural world. Being able to pick out a lion crouched in tall grass is a definite survival advantage.

Now, the question at hand… frankly I don’t know. Is there a set color gamut in our heads for those of us with “full” color vision and are all possible points in the gamut covered by some object or another in the environment? I think this is a good question.

Feynman was a wonderful physicist, but a mediocre psychobiologist. Also much fruitful study on these matters has been done since his death. Ideas about sense and perception have been changing quickly over the last few years, especially since the advent of the fMRI.

Hallucination it is, then? Let’s see you drive on a strange obstacle course on ketamine or LSD. ;)

Well, you are right, hallucination isn’t the right term for what’s really going on, but it’s not a terrible way to think about vision – it is a series of tricks performed largely in the frontal and temporal lobes after the signals have been processed in the occipital lobe.

The funny bit with Dick I’m referring to is at 1:15:12 in this video. :)

Oy I love him, and I miss him.

Colors are not just a reflection. They are also an emission. For example, gases in space emit colors at specific frequencies when said gases are charged (ionized). Hence, emission nebulae. Reflection nebulae occur as well, but their source is an emission, whether by a charged gas or the naturally occurring spectral color of a star. So we don’t need an object to see reflected color…we can see it directly too.

In the same way, all colors are quite natural, even fluorescent ones. For example, a neon sign…put an electric charge in neon and you get red. Add other gases, like argon, and you have a palette of possibilities. “Neon” signs aren’t just neon.

If it’s a frequency of light that we perceive in the visual-human spectrum (typically from 400 to 700nm) it is naturally occurring. As an astronomer myself, it’s obvious that kids have a better ability to see color than adults do, both in frequency and in amplitude…our eyes become desensitized a bit as we age.

Regardless, to see color, you must have the right receptors and receivers. Ask a dog, and he’ll lament that this is true. Poor color-blind doggy!

I think the question more specifically pertains to “weather or not any colors exist in the man made construction that do not exist on planet earth outside man intervention?”

The term natural implies not involving humans. Otherwise there would not be anything that is unnatural.