# Colors that we could normally see

• Medical
NeedBioInfo
Could somebody give me a list of all the colors that we could normally (Except for when we're color-blind, etc) perceive?

Also, could somebody give me a list of all the different shades, etc (Eg an illustrated list) that we could normally (Except for when we're color-blind, etc) perceive? Or at least, for example, a numerical amount of the shades that we could normally perceive?

Thanks

## Answers and Replies

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We can see anything in the visible spectrum of wavelengths...the entire range from red to violet, and any shade from white to black.

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The "colors" we see that you refer to is not entirely correct.

Humans can perceive light of frequencies between roughly 400 nm +/- 50nm to 700 nm +/- 50nm. We associate color with wavelength: violet (400 nm), blue, green (500 nm), yellow, orange, red (700 nm)

Here you can see just how exactly the eye converts those frequencies into colors that you perceive: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/V/Vision.html

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NeedBioInfo
I guess what I'm looking for is a list of all the colors/shades (preferably illustrated) that are associated with (preferably identified) wavelengths.

Anyways, thanks

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something like this?
http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html [Broken]

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There's an article in the latest American Scientist that you may find interesting:

http://www.americanscientist.org/template/AssetDetail/assetid/45931
Charting Color from the Eye of the Beholder

A century ago, artist Albert Henry Munsell quantified colors based on how they appear to people; specializations of his system are still in wide scientific use.

Everyone knows the particular shade of yellow that adorns all school buses across the United States. But how do we define exactly what shade this is, and reproduce the same color from coast to coast? Much of the standardization of colors stems from the century-old work of Alfred Munsell, who created one of the first colorimetry systems defined by how people see color: lightness, hue, and chroma (how much the apparent hue differs from neutral grey). Munsell's color charts have been customized for different fields, and are still in use in areas as diverse as beer brewing and soil science.

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The wavelenghts of light, even white light, are a finite set, so in principle there should be a precise number of colors within the range of human vision. But then there is the limit of out ability to distinguish between colors, which I would imagine is the limiting factor. IIRC we can see something like a million colors, but this could be way off.

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Ivan Seeking said:
The wavelenghts of light, even white light, are a finite set, so in principle there should be a precise number of colors within the range of human vision. But then there is the limit of out ability to distinguish between colors, which I would imagine is the limiting factor. IIRC we can see something like a million colors, but this could be way off.
There seem to be at least that many shades of beige at the Home Depot paint counter.

The ability to distinguish between colors seems to vary more among individuals. I wonder if anyone has ever directly tested this though. Maybe people who claim they can't tell the difference between two colors that someone else is asking them to choose between could if they cared to pay any attention to the task.

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What is it that I heard about recently... I think men have fewer rods and cones than do women, so we are entitled to dress like nerds...ie the colors don't match. Anyway, the idea was that women can see more colors than men, I think.

Sorry to be so vague but I barely remember hearing about this somewhere.

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NeedBioInfo
Could you clarify what you're referring to by IIRC? Infrared Remote Controller? Could we use that to see something like a million colors?

Thanks

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Staff Emeritus
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If I recall correctly = IIRC

NeedBioInfo
Could we use that to see something like a million colors? You seemed to indicate that when we're in that we can see like a million colors...

thanks

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NeedBioInfo
Hypothetically, I mean. like if we altered ourselves genetically or something

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You apparently missed my last post. We posted simultaneously.

IIRC = If I recall correctly

Simetra7
I have often wondered whether it would be possible to imagine a colour that does not exist, like a new primary colour other than red blue or yellow. I don't recommend thinking about this for too long though as it does tend to turn your mind inside out a bit!!!

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Ivan Seeking said:
What is it that I heard about recently... I think men have fewer rods and cones than do women, so we are entitled to dress like nerds...ie the colors don't match. Anyway, the idea was that women can see more colors than men, I think.

Sorry to be so vague but I barely remember hearing about this somewhere.

Might this be it?

http://www.psycport.com/stories/ascribe_2004_07_14_eng-ascribe_eng-ascribe_014026_988726893508805748.xml.html [Broken]

Some snippets:

COLLEGE PARK, Md., July 7 (AScribe Newswire) -- It's long been known that color blindness is caused, usually in men, by changes in the red and green opsin genes, the genes that enable humans to perceive color. But a new study of randomly selected people from geographically diverse populations shows that normal variation in the red opsin gene may have been maintained by natural selection to give humans, especially women, a better perception of color.

[...]

However, Verrelli and Tishkoff show that color vision changes can be beneficial too. Because females can have two different versions of this gene, but men can have only one, females may be able to perceive a broader spectrum of colors in the red/orange range. "Men and women may be literally seeing the world differently," Tishkoff said.

[...]

Those variations may have been especially important, Verrelli and Tishkoff speculate, in a time when humans were hunter-gatherers. Enhanced color perception would have allowed women, who were traditionally gatherers, to better discriminate among colored fruits, insects and background foliage.

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Simetra7 said:
I have often wondered whether it would be possible to imagine a colour that does not exist, like a new primary colour other than red blue or yellow. I don't recommend thinking about this for too long though as it does tend to turn your mind inside out a bit!!!

That would almost definitely be impossible. When you imagine colors and visual images in your mind's eye, the same general parts of visual cortex that 'light up' when you perceive external visual stimuli are activated. In other words, your conscious visual experience depends on the structure and function of your visual cortex, and all visual imagination can do is activate these pre-existing structures in visual cortex. To experience a new primary color you would likely need to add a whole new set of neural structures to visual cortex.

NeedBioInfo
Hi, Sorry. I realize now that by IRC you meant If I recall correctly = IIRC haha I think I either missed your post or thought you meant if you recall correctly IRC was something like an infrared remote controller or something :p

Anyways, I was just wondering, would it be possible for us to see like a million colors? Could you elaborate more on this?

Thanks!

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Hi,
You're already seeing millions colours!
and eye definition is largely far from our best screens.

NeedBioInfo
So we could hypothetically see a million different colors if it wasn't for the fact that we have "screens" like eye definition and the ability to distinguish between colors?

Gold Member
I meant that a 22' screen is a poor eye.
An eye is like a 2200' screen... A pretty huge definition.

NeedBioInfo
So what's the biggest definition an eye could (hypothetically) have?
What's the biggest definition a human eye could have?
(The bigger the definition, the better the range of visible colors, etc, right?)

Thanks

NeedBioInfo
So if I wanted a list of all the different colors that we could hypothetically percieve..it would be like a list of a million colors?

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The cones in our eyes sample the incoming radiation at three to five overlapping frequency windows, and pass the averaged intensity amount in each window to the primary visual cortex. The primary VC does a subtraction between the amounts to generate three parameters. Apparently each color we can distinguish is identified with some triple of these parameters. All of this is analog and threrefore at least implicitly continuous. So it COULD be that the number of distinguishable colors is potentially a continuum. This is supported by the fact that each color we are aware of is actually a range, and that people introduce new named colors by subdividing these ranges.

NeedBioInfo
okay...thanks

Could I get a list of all the colors (that are associated with wavelengths) that are visible to us at the moment though? like green, blue, orange, etc?

Thanks

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NeedBioInfo said:
okay...thanks

Could I get a list of all the colors (that are associated with wavelengths) that are visible to us at the moment though? like green, blue, orange, etc?

Thanks
How could you list something that's potentially a continuum? Anyone can make up names for colors, but how would that be helpful? There's no standard naming scheme. Three people can look at the same color and one will say it's "green," another will say it's "sage," and a third will say it's "celery;" the paint manufacturers might call it #12B-106. You can look up the range of wavelengths in the visible spectrum, and that's about all we could provide that would be consistent.

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selfAdjoint said:
The cones in our eyes sample the incoming radiation at three to five overlapping frequency windows, and pass the averaged intensity amount in each window to the primary visual cortex. The primary VC does a subtraction between the amounts to generate three parameters. Apparently each color we can distinguish is identified with some triple of these parameters. All of this is analog and threrefore at least implicitly continuous. So it COULD be that the number of distinguishable colors is potentially a continuum. This is supported by the fact that each color we are aware of is actually a range, and that people introduce new named colors by subdividing these ranges.

Wouldn't this be continuous only in principle? Ultimately there must be a finite number of quantum states and a minimum level of detection for any change.

Simetra7
NeedBioInfo said:
okay...thanks

Could I get a list of all the colors (that are associated with wavelengths) that are visible to us at the moment though? like green, blue, orange, etc?

Thanks

If you are talking about the colours that we see when white light passes through a prism they are; red, orange, yellow, green, blue, indigo and violet.
As for a list of all visible colours these are all just varying shades and mixtures of the above colours and subject to renaming at the whim of the person who happens to be describing the colour at the time. I don't think there could possibly be a universally recognised list of all known colours.

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worth the read, and...
...The actual estimate for how many different colors the human eye can distinguish varies between one and ten million, depending on the reference which you consult. However, the perception of color varies from one person to another, so there can be no single number that is true for everyone. The number of different colors that you, as an individual, can distinguish also varies dramatically according to the conditions; it drops to zero in low light conditions, in which only the rod cells of the retina can function, as the cone cells of the retina are required for color vision...
http://www.pburch.net/dyeing/dyelog/B1063361308/C128544578/E1447734446/

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Ivan Seeking said:
Wouldn't this be continuous only in principle? Ultimately there must be a finite number of quantum states and a minimum level of detection for any change.

But not a fixed, hard limit. It would come and go, affecting this hue and then that one, and probably only blur some subtle shade, such as I think we all experience now and then. The point is that there isn't any definite upper limit in the physics, although there may be one in the neural processing.

NeedBioInfo
So I could get a list of every wavelength that a color/shade is associated with and produce a list (illustrated with colors/shades instead of names) of all known colors/shades that way right?

Thanks

zoobyshoe
Simetra7 said:
I have often wondered whether it would be possible to imagine a colour that does not exist, like a new primary colour other than red blue or yellow. I don't recommend thinking about this for too long though as it does tend to turn your mind inside out a bit!!!
Sometimes when I'm drawing with my colored pencils, I come to a point where I've already used a lot of all the main colors and desperately wish there was a new one.

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I have often wondered whether it would be possible to imagine a colour that does not exist, like a new primary colour other than red blue or yellow. I don't recommend thinking about this for too long though as it does tend to turn your mind inside out a bit!!!
Easy. Ultraviolet, infrared, to name merely two. We cannot see them, but other animals can. It is easy to extrapolate this and realize that arbitrarily longer or shorter wavelenths of EM radiation that can be picked up in a high enough definition and interpreted by the brain as a spatial pattern can be a colour.

As to what we'd see if we were sensitive to these colours, who knows, since it would require a rewiring of our brain to do so.

If you are talking about the colours that we see when white light passes through a prism they are; red, orange, yellow, green, blue, indigo and violet.
There is no Indigo. There are only six colours in a rainbow. Newton made up the 7th out of superstition.

So I could get a list of every wavelength that a color/shade is associated with and produce a list (illustrated with colors/shades instead of names) of all known colors/shades that way right?
Perception is a tricky thing. You can combine two colours in the same space and get a colour that is perceivable, yet not correlated with a single frequency of light. A red and green cross-hatched swatch will not be representable by a single wavelength of yellow. Human perception is fuzzy that way.

Note, BTW, that magenta does not exist in a natural rainbow, now does it exist in nature. Magenta can only be formed from a combination of two frequencies which are at opposite ends of the spectrum.

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NeedBioInfo
So I could get a list of every wavelength that a color/shade is associated with and produce a list (illustrated with colors/shades instead of names) of a fair amount of known colors/shades that way right?

gerben
You could do this for monochromatic light (i.e. light consisting of only one wavelength), you would then get a list like the colors in a rainbow going from violet to red (about 400 to 700 nm wavelength). But the light around you is hardly ever monochromatic and the nervous system assigns a color to all the almost infinite possible combinations of different wavelengths, so that would make a ridiculously long list.

Also, light consisting of the same wavelengths can give a different color depending on the colors surrounding it, which would be problematic for your list. The color of a patch in a visual scene is a function of the light from a large part of that scene, and not only of the light coming from that patch.
(not only the wavelengths are important but also the relative intensities of the different wavelengths)

http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html [Broken]

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