Colors

[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

[Moonbear]

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

[cronxeh]

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

[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

[Math Is Hard]

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

[Math Is Hard]

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.

[Ivan Seeking]

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.

[Moonbear]

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. :biggrin:

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.

[Ivan Seeking]

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.

[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

[Ivan Seeking]

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

[NeedBioInfo]

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

[Ivan Seeking]

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!!!

[hypnagogue]

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?

Evidence That Men, Women Literally See the World Differently: Study Shows Color Vision May Have Been Adaptive During Evolution (http://www.psycport.com/stories/ascribe_2004_07_14_eng-ascribe_eng-ascribe_014026_988726893508805748.xml.html)

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.

[hypnagogue]

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!

[somasimple]

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?

[somasimple]

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?

[selfAdjoint]

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

[Moonbear]

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.

[Ivan Seeking]

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]

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 dont think there could possibly be a universally recognised list of all known colours.

[Ivan Seeking]

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/

[selfAdjoint]

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]

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 alot of all the main colors and desperately wish there was a new one.

[DaveC426913]

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.

[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)

A "list" for monochromatic light (http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html)

[NeedBioInfo]

Hypothetically, what ways could this ridiculously long list be made?
Thanks

[gerben]

You would have to list all the different "chromatic situations" (i.e. descriptions of the spectral content of the scene) and associate each of those with a name for the color that it gives. You would have to determine which of those situations give the same color and give those the same color-name. Whether any two give the same color could be established by asking human subjects.

[zoobyshoe]

Hypothetically, what ways could this ridiculously long list be made?
Thanks
What is it you want this list for? For all practical purposes, as people have mentioned, the road from red to violet is a continuum.

In reality none of the colors around us is pure, and it's pretty much arbitrary what you call anything. A tint somewhere between green and yellow, but more toward green, might be called "lime", but that is just for marketing purposes for fabric, or paint, or formica or whatever. "Lime" doesn't correspond to any exact position between red and violet because it will have white mixed in, and who knows what else. Pigments and dyes have particular qualities depending on what they're made of.

For an artist to paint a "green" leaf 10 different colors may have to be employed. "Greenness" is only the overall dominant impression you get when looking at a leaf. There are highlights and shadows, and alot of plants we call green actually have alot of brown in them, and brown is already a complex shaded orange. Some "green" plants have alot of subtle red streaks, and some have alot of blue, and some are very yellow, depending on how the light hits them.

Things colored with pigments and dyes are intended for viewng in white light, and this is a different situation than trying to parse visible light into monochromatic "quanta" that can be named. For the latter no one ever gets much more detailed than, say, "red-orange" or "yellow-green", or "violet-blue".

With pigments and dyes you can get really creative: "raspberry," "chartreuse," "ecru," "tuscan red," "rosey beige," "midnight blue," and so on. There is no end to the combinations you could make and give names to.

[fuzzyfelt]

What is it you want this list for? For all practical purposes, as people have mentioned, the road from red to violet is a continuum.

In reality none of the colors around us is pure, and it's pretty much arbitrary what you call anything. A tint somewhere between green and yellow, but more toward green, might be called "lime", but that is just for marketing purposes for fabric, or paint, or formica or whatever. "Lime" doesn't correspond to any exact position between red and violet because it will have white mixed in, and who knows what else. Pigments and dyes have particular qualities depending on what they're made of.

For an artist to paint a "green" leaf 10 different colors may have to be employed. "Greenness" is only the overall dominant impression you get when looking at a leaf. There are highlights and shadows, and alot of plants we call green actually have alot of brown in them, and brown is already a complex shaded orange. Some "green" plants have alot of subtle red streaks, and some have alot of blue, and some are very yellow, depending on how the light hits them.

Its probably just confusing the issue, but in treatise on the colour system, Itten equated colours with a continuum of mental and emotional expressive values-

red+yellow=orange
power+knowledge=proud self respect

red+blue=violet
love+faith=piety

yellow+blue=green
Knowledge+faith=compassion

Is listing colours like trying to list all mental and emotional states?

[NeedBioInfo]

No I just...my ex-boyfriend was an artist and I thought it would be neat to really embrace the world of color even if I can't draw. Sorry I know that doesn't make sense. I guess I just wanted to go up to him some day and say like "Look! I know ALL THE COLORS THAT EXIST! I have them right here so I can be aware of them all the time! That makes me kind of artistic doesn't it?"

It's not that I have issues. It's just complicated. Oh, wait, it is that I have issues...okay, well, never mind

[somasimple]

Hi,

here is some colours with their names (click for complete chart)
http://www.bachlabel.net/newsite/color_chart.html

[Simetra7]

No I just...my ex-boyfriend was an artist and I thought it would be neat to really embrace the world of color even if I can't draw. Sorry I know that doesn't make sense. I guess I just wanted to go up to him some day and say like "Look! I know ALL THE COLORS THAT EXIST! I have them right here so I can be aware of them all the time! That makes me kind of artistic doesn't it?"

It's not that I have issues. It's just complicated. Oh, wait, it is that I have issues...okay, well, never mind


Maybe you would be better off borrowing some art books from the library. There are some really great ones with heaps of info about mixing colours and how colours interact with each other in an artistic sense. You really don't need to be able to draw well to create beautiful works of art with colour.

[zoobyshoe]

Maybe you would be better off borrowing some art books from the library.
Yeah. Just get a couple books with titles like How To Paint With Oil Colors, and there is sure to be an explanation of the color wheel. That tells you how to mix colors from primaries.

Then you could visit art stores and just look at the paints, colored pencils, colored markers, etc and see what they're called.

[fuzzyfelt]

Yeah. Just get a couple books with titles like How To Paint With Oil Colors, and there is sure to be an explanation of the color wheel. That tells you how to mix colors from primaries.

In which case Itten's The Art of Color, or The Elements of Color, are a good place to start. He explains how to construct a regular 12 hue colour circle, starting with the primaries red, yellow and blue, mixing equal amounts of two of these respectively to make secondaries(orange, green and violet), and then mixing equal amounts of the colours nearest each other to make yellow-orange,red-orange, red-violet,blue-violet,blue-green and yellow-green. These could be further mixed to make 24 or 100 hue circles, but he says there is not much point, an artist needs to be able to have a mental picture of the wheel, not obscured by too many hues.
There are the achromatic colours, too -black (which is very hard to make this way, but correctly is made useing all the hues) and white, and these add to or subtract brilliance from the 12 hues. Hues have differing brilliances ( for example,red and green are equally brilliant, yellow is more and violet less) and to completely incorporate those into a colour wheel would be to add varying amounts of black or white to each hue, creating rather than a colour wheel with 12 hues, a sphere of 144 shades, moving from white at the top, to black at the bottom.
Then within there would be a neutral grey area running vertically down the centre, and taking a horizontal cross section, by adding measures or their tonally opposite colours, these colours would gradually become saturated to meet the grey in the middle.
'By painting all the horizontal and vertical sections of the sphere in this manner, we complete our color catalogue. Horizontal sections contain the degrees of saturation of the hues, and vertical sections contain the tints and shades of a given pair of complementaries, pure and diluted'.

It is how this is used that is really important to artists, with different types of contrasts- hue, Dight-dark, cold-warm, complementary, simultaneous, saturation and extension, amongst other things to do with colour.

Did your ex boyfriend paint? What sort of art does he like?

[Moonbear]

No I just...my ex-boyfriend was an artist and I thought it would be neat to really embrace the world of color even if I can't draw. Sorry I know that doesn't make sense. I guess I just wanted to go up to him some day and say like "Look! I know ALL THE COLORS THAT EXIST! I have them right here so I can be aware of them all the time! That makes me kind of artistic doesn't it?"

It's not that I have issues. It's just complicated. Oh, wait, it is that I have issues...okay, well, never mind
This may come across a bit blunt, but just knowing colors isn't what makes you artistic. That would be somewhat like saying memorizing all the words in a dictionary would make you a poet. You may simply be too technical in your thinking to really relate to the creative/artistic side of things. Maybe it's good that he's an "ex" boyfriend if you think and view the world from such very different points of view as to make it difficult to relate to each other.

Did spending time with him give you the desire to develop more artistic/creative thinking, or was some competitive side just trying to play a game of one-upmanship because he had a talent you don't have?

[NeedBioInfo]

Well I know that: A: there's more to being an artist than simply knowing and applying knowledge of color

And B: Without being able to apply the knowledge of color, the knowledge wouldn't be very much use

But I mean, I thought that if artists were more aware of color (and as a result able to use color better) their artistic abilitie(s) would improve. Anyways that was my line of thinking

This thread/desire didn't really have anything to do with him originally (Well maybe it did without me realizing it) but then I thought it would be neat to be able to relate to him (in regards to this thread) if I ever saw him again, which I might not. I think I also thought later that me making this thread DID have more to do with him than I thought.

[NeedBioInfo]

But anyways Gerben said that my list could be made by

listing all the different "chromatic situations" (i.e. descriptions of the spectral content of the scene) and associating each of those with a name for the color (The different ones, not the identical ones) that it gives.

[NeedBioInfo]

(I edited the above two posts so um, read them again I guess to make sure you didn't miss the editing) (thanks)

[NeedBioInfo]

I mean, would it be possibly to just list- with colors, not names- all the different "chromatic situations" (i.e. descriptions of the spectral content of the scene)?

[NeedBioInfo]

Somebody said this:

"list all the different "chromatic situations" (i.e. descriptions of the spectral content of the scene)"

What does it MEAN though? How would you do that? etc

thanks

[gerben]

Spectral content just means the wavelengths and the intensity of those wavelengths. To describe the spectral content of a scene you would have to describe the wavelengths (and their intensities) of the light coming from every point in the scene.

This is quite complicated, it depends on the direction from which you look onto the scene and on (the spectral content of) the light that illuminates the scene, but nowadays there are devices that can measure this.

The spectral content describes the physical aspects of the light coming from the scene. However, humans experience this as a scene filled with colors, that is what I meant with "chromatic situation": in human beings the physical situation (i.e. the spectral content of the scene) gives rise to a chromatic interpretation (i.e. a colorful scene).

[Moonbear]

Somebody said this:

"list all the different "chromatic situations" (i.e. descriptions of the spectral content of the scene)"

What does it MEAN though? How would you do that? etc

thanks
This is from the color thread:
http://www.physicsforums.com/showthread.php?t=88705&page=2&pp=20

If you're going to quote someone here, use quote tags and identify the person/source you're quoting (in this case, the quoted text was written by Gerben). There's no need to start a new thread every time you have a question about someone's reply in a previous thread; the point of a discussion is you can ask them to clarify or explain in the same thread. Why have someone else try to explain what a member meant in a reply when you can ask them directly in the thread they posted it in? When you quote it out of context, you lose meaning. In the proper context, the answer to your second question was partially answered in the other two sentences of Gerben's reply.

You would have to determine which of those situations give the same color and give those the same color-name. Whether any two give the same color could be established by asking human subjects.

It would be a ridiculous undertaking though. The other replies in that thread already pointed out how difficult it would be. You could come up with A list, but I doubt you could ever come up with a comprehensive or complete list.

[Bio-Hazard]

It would be a ridiculous undertaking though. The other replies in that thread already pointed out how difficult it would be. You could come up with A list, but I doubt you could ever come up with a comprehensive or complete list.

Because of that from lack of digital device being able to go through the complete range of analog color, would that be? :biggrin:

Digital devices have their limits.

[hypnagogue]

Please note that the last four posts in this thread were originally posted in a separate thread titled "phrase." Since "phrase" was merely a continuation of the discussion started in this thread, I have merged the two together.

[hypnagogue]

It would indeed be impractical to try to exhaustively list all the chromatic situations one could possibly come across. For instance, suppose we take a very simplified situation-- suppose we want to find the number of chromatic situations one could display on a computer monitor. Suppose we ignore the environment in which the computer monitor is viewed, and suppose that we hold viewing distance, lighting conditions, and angle of view constant. Suppose the computer monitor has a 1024x768 resolution, with each pixel capable of displaying one of 16,777,216 colors. (These are fairly standard settings for a computer monitor.)

So what can our monitor display? Since it's at 1024x768 resolution, it has 1024 * 768 = 786,432 pixels. Each of these pixels can display one of about 16.8 million colors, so the range of possible displays on the monitor is

786,432 pixels * 16,777,216 colors/pixel = 13,194,139,533,312 chromatic situations!

So even in a highly constrained and artificial scenario like the one outlined above, for a single computer monitor, there are over 13 trillion chromatic situations. Of course, that number balloons even larger if we take into account lighting conditions or the visual content of the surrounding environment, etc. So, no, it's probably not a good idea to bother trying to come up with all the possible chromatic situations.

[NeedBioInfo]

My dad said this:

There are 16,777,216 ^ 786,432 chromatic situations, where "^" means* "to the power of".* Since there are only about 10 ^ 80 atoms in the* universe, you would need a much larger universe in order to create a* list long enough to list all the chromatic situations.

so I'm looking for info about that...
thanks

[hypnagogue]

whoops, sloppy mistake on my part. Your dad did the calculation correctly.

What further information can you want though?

[NeedBioInfo]

I guess I just wanted to check that that was correct, and, if it wasn't, to find out about it

anyways, thanks

[hitssquad]

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?The best information you can get on this is at Hyperphysics (I think you might want to be sure to follow all of the links from this primary link):
hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html (http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html)

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/imgvis/colcon.gif

http://hyperphysics.phy-astr.gsu.edu/hbase/vision/imgvis/cie4.gif

[fuzzyfelt]

The best information you can get on this is at Hyperphysics

Great link!
Especially if the aim of this thread is, as it says, perception of colour.
If the thread is for painting then how this perception is translated by pigments is also important.

[fuzzyfelt]

I felt I had better correct my mistake.

Thanks to this thread my understanding of pigment colour theory has undergone a much needed (though still learning) overhaul -

that the artist's traditional colour wheel has been considered incorrect since 2004, and a new (though considered fallacious) theory replaces the pigment primaries of red, yellow and blue, with subtractive 'primaries' yellow, cyan and magenta - http://www.handprint.com/HP/WCL/color5.html ;

or another view that involves primary pigments of red, yellow, blue and green - http://plato.stanford.edu/entries/color/.

Thanks for making this thread, as it (finally) helped me question some things I had taken for granted.