Humans can see 3 colors, sometimes we can see more one color at the same time, this creates 7 variations of colors and a few million different shades of those same 7 colors. blue, red, green = mix them and you get : white, black, purple, yellow. Any other colors like brown or magenta or pink, are just different shades, some clearer some darker, turn off the light in your room and something that reflects red or orange light will turn brown. Want to turn yellow into orange? well to get yellow you mix red and green, add more red to make it darker.

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this is about creature design, I need to know if to see different colors, more colors than we already see and not just more shades of those 7 colors but more base colors. Like blue+green+red+something_else. Do we need different eyes or a different brain, maybe both? Could some type of technology enable their users see more colors without changing their brains? I'm thinking about a colorblind species that can see way more colors than humans after wearing a special pair of googles, would it be possible? This is not a secondary question but a continuation of the main question, if colours are in the brain and not the eyes, does that mean that colours don't really exist and that the world is actually just shades of grey and our brain creates those artificial different colors to better help us distinguish those shades of grey?

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    $\begingroup$ Birds can see the world very differently from us, because unlike us, birds can perceive UV light. Birds have one brain and 2 eyes just like us. You wouldn't even need more eyes to do the same, just more photoreceptors $\endgroup$ Jan 5, 2022 at 15:49
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    $\begingroup$ There are no colors in the 'real world', no 'shades of grey' either. There are only different wavelengths of light in the EM spectrum. No 'difference in the brain' is going to change that fundamental reality. 'Special goggles' can transduce the wavelength, as in infrared goggles, It is what the brain DOES with the information about those wavelengths that results in 'color', or even 'shades of grey'. $\endgroup$ Jan 5, 2022 at 15:51
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    $\begingroup$ Take a look at shrimp mantis eyes. In addition to 16 types of photoreceptors they are also sensitive to different types of polarization. google.com/amp/s/phys.org/news/… $\endgroup$
    – UVphoton
    Jan 5, 2022 at 17:58
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    $\begingroup$ You need different eyes. theoatmeal.com/comics/mantis_shrimp $\endgroup$
    – LSerni
    Jan 5, 2022 at 20:35
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    $\begingroup$ Related to mantis shrimp: worldbuilding.stackexchange.com/questions/48888/… $\endgroup$
    – Rob Watts
    Jan 5, 2022 at 20:50

7 Answers 7


What is "see"? Could it be "perceive?"

In humans it is possible for perception types to overlap. This is synesthesia.


The word "synesthesia" has Greek roots. It translates to “perceive together.”...

One of the most common responses is to see letters, numbers, or sounds as colors. You might also:

  • See or hear a word and taste food
  • See a shape and taste food
  • Hear sounds and see shapes or patterns
  • Hear sounds after you smell a certain scent
  • Hear sounds and taste food
  • Feel an object with your hands and hear a sound

It can be an annoyance. Children say it can make reading tricky when they see colors that other people don’t. If you have taste-related synesthesia, it can be startling when a bad taste comes on suddenly. But most synesthetes see their condition as a sixth sense, not a drawback.

Your colorblind aliens have smell, taste and hearing similar to ours. When they wear Jordy's visor to see colors, the visor taps into those other sensory modalities so their brains can make sense of them.

This has the added immense benefit of you being able to convey the sensations to your readers, because prose is full of words for sensory perceptions beyond color, and you can use all of them.

"How do I look?" She did a pirouette.

Buj peered through the visor. "Like... cinnamon?" it ventured. "And cowbell. And burning pizza."

She paused. "Is that good?"

  • $\begingroup$ yeah I know synesthesia, I always thought that it was normal for letters to have colors and numbers to have tastes, realized it wasn't supposed to be normal in middle school $\endgroup$
    – Drien RPG
    Jan 5, 2022 at 18:33
  • $\begingroup$ @RPGlife Oh cool, I've got grapheme-color synesthesia (the kind where letters/numbers have colors). I've never talked to anyone with a taste-based synesthesia, so out of interest, what sorts of tastes are they? And, do 1, 2, and 3 have associated tastes that are similar to the ones for white, black, or red? (sorry for all the questions :p) $\endgroup$ Jan 6, 2022 at 3:08

Tetrachromacy can happen in humans already

People with two X chromosomes could possess multiple cone cell pigments, perhaps born as full tetrachromats who have four simultaneously functioning kinds of cone cell, each type with a specific pattern of responsiveness to different wavelengths of light in the range of the visible spectrum. One study suggested that 15% of the world's women might have the type of fourth cone whose sensitivity peak is between the standard red and green cones, giving, theoretically, a significant increase in color differentiation.

In humans, preliminary visual processing occurs in the neurons of the retina. It is not known how these nerves would respond to a new color channel, that is, whether they could handle it separately or just combine it in with an existing channel. Visual information leaves the eye by way of the optic nerve; it is not known whether the optic nerve has the spare capacity to handle a new color channel. A variety of final image processing takes place in the brain; it is not known how the various areas of the brain would respond if presented with a new color channel.

It seems that changes would need to happen both in the retina and in the brain to properly process and interpret the additional channel. Which sort of makes sense: attaching a screen to a radio doesn't make a working TV.

  • $\begingroup$ At least some tetrachromats are able to see a wider range of colors than average people. bbc.com/future/article/… $\endgroup$ Jan 6, 2022 at 6:20
  • $\begingroup$ The X-mosaicism theory of tetrachromacy suggests it should be common, but instead it seems to be vanishingly rare. The Wikipedia article says that Gabriele Jordan found one candidate tetrachromat in 20 years of research. So I think we do know how the visual system adapts to a fourth cone type: in the vast majority of cases, it doesn't. (That or the X-mosaicism theory is wrong.) $\endgroup$
    – benrg
    Jan 6, 2022 at 8:55
  • $\begingroup$ Ummm, many vendors sell configurations of lights that show different frequencies and intensities of light that depend on the pitch, volume, and timbre of sound, and connect it to their speakers. Connecting a screen to a radio. Not really a 'tv', but intriguing in its effect nevertheless. Alternately, speakers that respond to changing light in the environment - a particular sound matched to a specific wavelength. Artificial synesthesia. $\endgroup$ Jan 7, 2022 at 15:51

You should study more about how the eye works

Color is the result of your brain interpreting signals from the eye. The human eye has photoreceptors that are sensitive to the certain wavelengths of light that we call red, green, and blue. Take a look at this chart from the Wikipedia article on color - it shows how much the different photoreceptors react to a given wavelength of light. As others have mentioned, all colors we see are simply all the various combinations of stimulation levels of our red, green, and blue color photoreceptors.

Consider the color yellow. If you are exposed to light with a wavelength 575–585 nm, your eyes will send a signal to your brain that gets interpreted as seeing something yellow. If you look at the chart again, you'll see that at 575 nm, both the red and green photoreceptors should have a fairly strong reaction. Computers take advantage of this when displaying colors to you - the RGB value for yellow is #FFFF00. For anyone unfamiliar with RGB values, this is interpreted as 255 red, 255 green, 0 blue. So a computer doesn't produce 575 nm light, it gives you a mix of red and green light. The end result is that your red and green photoreceptors both react - the exact same signal for 575 nm light.

So how could someone see new colors? Their brain needs to receive more information. Suppose you had a fourth type of color photoreceptor in your eye sensitive to light between green and blue. Without that fourth kind, a mixture of green and blue (#00FFFF) is interpreted as cyan. With the cyan photoreceptor, you would be able to see more colors - a mixture of green and blue light would strongly stimulate those two photoreceptors and only weakly stimulate the cyan one, while cyan light would strongly stimulate the cyan photoreceptor and weakly stimulate the green and blue ones. This means that your brain would have a way to distinguish between cyan and a mixture of green and blue, and as a result you would see those two scenarios as two different colors.

Could a colorblind being use something to see more colors than us?

A completely colorblind species would receive a relatively simple signal from their eyes - how much light is coming in. To see more colors than us, they would need to receive more information than us. Their eyes are not suited for this task. Special goggles can't fix this.

If you're thinking about the glasses that humans with certain kinds of colorblindness can use, that's a fundamentally different situation. The short explanation is that those people still have three kinds of color photoreceptors but they overlap even more than normal. The glasses are able to correct for that extra overlap. Again, their eyes are still sending three color signals to the brain.

So in order for the "special goggles" you mentioned to work, they have to bypass the alien's eyes. However they would do it, they'll just send more information to the alien's brain than our eyes do to our brains.

Interpreting that extra information is a separate problem. You could solve it by giving the aliens synesthesia as @Willk suggested - the color information comes through one of their other senses.

You could also solve it via neuroplasticity. When they first wear the special goggles, their brains start receiving information that they don't know how to interpret. Over time their brains learn how to interpret that information. If they're like humans, the younger they are the quicker their brains would be able to adapt.

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    $\begingroup$ What wavelength is purple? </trolling> $\endgroup$
    – fectin
    Jan 5, 2022 at 23:25
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    $\begingroup$ It's not true that you need to "bypass the eyes," if you have two eyes. You can put a colored filter in front of one eye and not the other (or different colors in front of the two eyes). This can give you as much as hexachromatic vision if you're a trichromat, or tetrachromatic if you're a dichromat, though how well the brain can learn to interpret the signals I don't know. This approach has been tried for color blindness in real life, as far back as the 19th century. $\endgroup$
    – benrg
    Jan 6, 2022 at 6:22
  • $\begingroup$ @fectin Purple is a wavelength shorter than blue that also happens to trigger the red receptors because the response curve for red actually has two peaks. d.umn.edu/~jfitzake/Lectures/UndergradPharmacy/… $\endgroup$
    – Brianorca
    Jan 6, 2022 at 16:42
  • $\begingroup$ If an eye visual appliance were able to filter out specific wavelengths of light. and presented to the eye only light of specific wavelengths, and then cycled through all of the 'colors' one at a time, the mind could be trained to the same 'cycle' and interpret the shades of grey at each wavelength as a specific perception, and through persistence of vision re-blend them together into a cohesive color 'picture'. That is, shades of 'grey' during the 'red' cycle perceived as 'red' blended with the perception of shades of grey during the 'green' cycle. $\endgroup$ Jan 7, 2022 at 15:27
  • $\begingroup$ @JustinThymetheSecond I suppose that is a way to provide more information while still sticking to grayscale, but I would have difficulty accepting that if I ran into that in a story. In a way it's kinda like the idea of subliminal messages (which don't work at all). You'd have to combine it with some sort of genetic engineering or brain implant to be able to interpret those flashes correctly. If you're going to go that far though, you may as well just send color signals instead of flashes. $\endgroup$
    – Rob Watts
    Jan 7, 2022 at 16:24

Color is not a physical quantity. It does not exist in nature. Color is a sensation. It exists only in the mind.

The physical quantity corresponding to the sensation of color is the power spectrum of light; just as the physical quantity corresponding to the sensation of pitch is (roughly speaking) the fundamental frequency of the sound. The relationship between the sensation of color and the physical spectrum of the light is very complicated and depends on many different factors; it also depends on the immediate history.

Sensation Physical quantity or quantities
Pitch Frequency of the fundamental. (But see missing fundamental for a tricky exception.)
Loudness Sound pressure and distribution of the sound power in the frequency spectrum.
Lightness Power of the electrmagnetic radiation and distribution of the power in the spectrum.
Color Distribution of power in the spectrum and spatial distribution of the light and immediate history of the observer.

So, obviously, to see more colors, whatever that means, you need both different eyes (so that they produce a richer set of signals from the spectrum of light) and a different brain (so that those signals can be interpreted).

About 15% percent of women have eyes which can produce four different fundamental color signals. (That's because it so happens that one of the photosensitive proteins responsible for color vision is encoded on the X chromosome; women have two X chromosomes, and one of them, chosen randomly, is shut down in each and every cell of the body.) But only very few of them have the corresponding brain and mind structures to make use of the four different signals.

And the idea that there are specifically seven colors and the rest are shades is not necessarily true, because the number of basic colors is a cultural construct. (Remember that color does not exist in nature, it exists only in the mind. And the minds of humans are very strongly influenced by the surrounding culture.)

Some languages have fewer than seven basic color terms, others have more. For example:

  • In Russian there is no basic word corresponding to what English calls blue. In Russian, goluboy (sky-blue) and siniy (dark blue) are fundamental colors, and they do not overlap; goluboy is not a kind of light siniy, and siniy is not some kind of dark goluboy. You simply cannot translate the sentence "I saw a blue car" into Russian without specifying what kind of blue that is. (Isn't the work of a translator fun?)

  • There must be something special with blue, because neither Roman Latin nor ancient Greek have words for what English calls blue. Sky-blue, yes. Blue-gray, yes. Blue-green, yes. Blue in general, no.

    (In the Middle Ages, Latin was used as an official and high-culture language throughout western Europe. Since all western European languages have a word for blue in general, usually derived from the Germanic *blāu, Medieval Latin adopted the word blavus.)

  • Translating colors from ancient Greek into English is an exercise in creativity, because broadly speaking the way ancient Greek names colors is fundamentally different from how English does it. Homer's wine-dark sea is a famous example.

In general, there is a very interesting theory of how color terms develop in a language.

Technically speaking, all the colors which can be perceived by the average human can be created by combining three different sources of light; this is the CIE color space. Unfortunately, the three theoretical sources of light of which the combination can produce all colors that can be perceived by the average human have non physical colors; one is a blue just a little bluer than the bluest blue which a human can perceive, one is a red redder than the reddest red a human can perceive, and the third is a green very much greener than the greenest green a human can perceive.

In real practice, you need at least four different fundamental colors to recreate (most of) the color gamut the average human can perceive.

  • $\begingroup$ Whether a color has a physics representation depends on the color model used. You could choose e.g. the "standard" RGB color system, where primary colors have a corresponding representation in biology/physics, as a peak perceived by one of the cone types. Just like vowel sounds in a sound spectrum, colors can be reconstructed from the power spectrum also, not in terms of language, but a given color mix can be approximated and reproduced from a given RGB power spectrum. No language or culture is involved, but the culture could e.g. allow some colors to be used more and recognized easier. $\endgroup$
    – Goodies
    Jan 5, 2022 at 17:19
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    $\begingroup$ @Goodies: The sRGB color space can represent less than half of the colors which can be perceived by a standard observer. It is literally impossible to represent all colors perceivable by a standard observer using three physically realisable primaries. In particular, sRGB is very deficient at representing greens (and oranges). The green primary of sRGB is a very unsaturated (and very unsatisfactory) green; it was chosen because the main design requirement of sRGB was to approximate the color reproduction of old school cathode ray tube TVs and monitors. $\endgroup$
    – AlexP
    Jan 5, 2022 at 18:48
  • $\begingroup$ @Goodies Re: Whether a color has a physics representation depends on the color model used. That's confusing. Colour is the sensation produced by light on the visual system. A colour model is a mathematical model, whereby colours are described by numbers, etc. What does physics representation mean? That it's spectral? That it can be obtained from lamps? $\endgroup$
    – Pablo H
    Jan 6, 2022 at 15:18
  • $\begingroup$ Re: need at least four different fundamental colors. I think you mean four light sources. Or perhaps chromaticities. $\endgroup$
    – Pablo H
    Jan 6, 2022 at 15:20
  • $\begingroup$ @PabloH: Yes, physically realisable chromaticities or light sources. But colors is good enough at the level of this answer. You may have noticed that the question suggests the OP has only a very naive understanding of color theory and colorimetry. $\endgroup$
    – AlexP
    Jan 6, 2022 at 15:44

The main component humans use to perceive color is the cones and rods in the eye. Retina Rods give you black and white vision in low light as the cones give you color vision by converting stimuli from selected light wave lengths to a neuro signal. The selected energy ranges each cone is sensitive to is pretty well defined across the species. Variations of this tend to cause color blindness.

At this point, the eye does little more than that, provide raw data for the brain to use. It is then up to the brain to convert this raw data into useful information.

This process is not an automatic process. You do not just get born, open your eyes and you make sense of the world around you. Once you first open your eyes, your brain gets to work processing this data and over time, it starts assigning certain values to certain information received by the building of neuro connections and synapses. Certain info it process is something like signal from cone 2=x, cone 3=y and rod 4= z => 2x+3y+4z= pink, or something like that and the neurons in your brain from then on out, when they see that combination again, your brain will always think "pink."

Now to address your question, there is several part to this.

To allow the eye to perceive different wave lengths, or to change the signal the retina produces for a given stimuli, you will need a new eye. If the signal 2x+3y+4z produced the raw data of 473.28nm to = pink and you want it to actually be 485nm, then the components in the eye need to be changed, which the way they work is based on genetic code from birth.

Now for the brain to see that 473.28nm signal and call it something else, is probably easier. If the synapsis and neuro pathways get disturbed and you are able to regain such connections, they will not form in the same way. So instead of seeing pink it perceives mauve, you would initially be shocked, but over time you will get use to it.

This change could be caused by trauma to the retina, optical nerve or brain damage. Usually, such trauma, at best usually results in color blindness. Rarely, it could shift the perceived spectra. There is a medical condition, which I am having difficulty finding it right now. Hopefully there is someone here that can find the link to it.


Colour perception doesn't work like you think.

In particular, magenta, purple and pink exist only in your brain.

The TL;DR is that the ideal average human pair of eyes can only perceive colours within this CIE colour diagram:

CIE diagram

(I suggest reading https://en.wikipedia.org/wiki/CIE_1931_color_space and related colour theory topics).

As you should be aware, light at a given wavelength produces a single colour. Those are the curve of the diagram. Now, when you have two light sources with different wavelengths, draw a line between their two points in the curve - the perceived colour will be alongside that line (closer to one or the other depending on the intensity).

An sRGB monitor, with its tiny red, green and blue lights, will be able to produce any colour within the triangle in that diagram.

So for creatures that can see into the infrared and ultraviolet (i.e. have receptor cells for infrared and ultraviolet), you should imagine extending that curve downwards; the shape of the curve will depend on the sensitivity of each kind of colour receptor cell.

Your role model is a shrimp

To see more colours, have more kinds of photorreceptor cells. Let me quote from the wikipedia article on the Mantis Shrimp:

The eyes of the mantis shrimp are mounted on mobile stalks and can move independently of each other. They are thought to have the most complex eyes in the animal kingdom and have the most complex visual system ever discovered. Compared with the three types of photoreceptor cells that humans possess in their eyes, the eyes of a mantis shrimp have between 12 and 16 types of photoreceptor cells. Furthermore, some of these shrimp can tune the sensitivity of their long-wavelength colour vision to adapt to their environment. This phenomenon, called "spectral tuning", is species-specific.


Mantis shrimp can perceive wavelengths of light ranging from deep ultraviolet (UVB) to far-red (300 to 720 nm) and polarized light. In mantis shrimp in the superfamilies Gonodactyloidea, Lysiosquilloidea, and Hemisquilloidea, the midband is made up of six omatodial rows. Rows 1 to 4 process colours, while rows 5 and 6 detect circularly or linearly polarized light. Twelve types of photoreceptor cells are in rows 1 to 4, four of which detect ultraviolet light.


Some species have at least 16 photoreceptor types, which are divided into four classes (their spectral sensitivity is further tuned by colour filters in the retinas), 12 for colour analysis in the different wavelengths (including six which are sensitive to ultraviolet light) and four for analysing polarised light. By comparison, most humans have only four visual pigments, of which three are dedicated to see colour, and human lenses block ultraviolet light. The visual information leaving the retina seems to be processed into numerous parallel data streams leading into the brain, greatly reducing the analytical requirements at higher levels.

The last bit can be also read as: since there's more information leaving the eye and entering the brain, the optic nerve needs to be wider/thicker, which would also mean that the first layers of neurons would be somewhat wider as well. That's arguably the only change required in the brain.


You need a new vision app to make you a docecachromat or whatever you like.

Imagine you have a standard camera-studded tech toy with accelerometers and thingamajigs so it can keep precise track of where every photoreceptor in your retina is at any given moment. Suppose it also has the ability to project a hologram with blue, neutral green (for rods), green (for green cones) and red lasers. And it can align the dots of this hologram reliably with the individual photoreceptors, putting the right color of light on each to set it off. And each one can be turned on or off relative to all the others.

Well, what would happen if you have this as an eye-mounted "appliance"? (rather than making it a pair of bulky glasses, let's say it uses a highly efficient and silent form of solid state flight to fly in formation with the user's head) All the while you wander the world, it is using its own sensors to do multi-spectral analysis on every pixel it sees. And it is mapping that information onto individual photoreceptors according to a plan.

You have an individual blue cone, born a blue cone, raised a blue cone ... now it sees a blue laser if an only if you're seeing ultraviolet light from that spot in the visual field. So without changing the protein, you've retroactively made it an ultraviolet cone. You've done the same with many different wavelengths. So the user's brain is busy remapping all this data to work as if they had been born with many different colors of cones. This is probably a terrible idea - remapping the retina means abusing the natural network, and I can't swear it will work. The lateral geniculate nucleus of the thalamus takes in blue cones at one layer, red and green at another ... it was able to handle splitting a yellow cone into green and red at some time in the past, but turning them into many colors might be a stretch. You might reduce visual acuity terribly, or confuse the wiring enough to cause dyslexia (which can be traced to differences in timing at the LGN). Make a note to volunteer someone else for the trial run. But if all goes well they will be Multi Spectral Super Soldiers, with all the wetware color recognition of a modern spy satellite. If there are five kif plants growing in an acre of industrial hemp, they'll be able to go rip each one of them out (for future law enforcement training sessions, I'm sure) like they were a different color ... because that is what happens, after all, when you mess with the plant's natural sunscreen.


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