Talk:Primary color

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[edit] Psychological Primary Colors

 Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion. (January 2007)

I'm surprised that this article doesn't explain the Psychological Primary Colors. Please put so in whatever article they are appropriate for. They were not invented by any Wikipedian; they are mentioned at http://dictionary.reference.com at "primary color", and at several Internet sites, as you can see by doing a Google search. 66.32.126.20 21:30, 3 Apr 2004 (UTC)

[edit] Old talk

"This is also lends some insight into why visible-light lasers tend to be only red, green, or blue. using combinations of colors creates frequency interference, causing the beam to become decollinated and to spread apart quickly. (But does it explain why lasers aren't orange, yellow, or cyan? Those colors can also be created with one wavelength.)"

There is nothing fundamental about these colors, they're just wavelengths. Color is arbitrarily determined by in the eye, depending on the intensity of the signal in one of the six different types of cone groups. For a quick proof by counterexample, the maser was invented before the laser (maser stands for Microwave Amplification by Stimulated Emission of Radiation, and has no color whatsoever)--BlackGriffen

I also removed:

This is the reason that television uses red, green, and blue phosphors. Any color combination can be represented by mixing different proportions of the primary colors. Note that in practice this is restricted by technical limitations of the medium, for example the television standard NTSC is noted for its inability to represent certain colors to retain backward compatibility with black and white televisions.

This isn't true at all. There's really no such thing a "primary" and "non-primary" color--the primaries are just whichever ones you choose to call primary, and the colors they can make with mixing are only those within the gamut of those your choose. Some make better choices than others, but let's not make it sound like there's some special property of red, green, and blue that make them magical or something. --LDC

What makes red, green, and blue special is that they correspond to the peak responses for the human eye's photoreceptors. Is that right? --Damian Yerrick

Well, yes, there is that. But the primaries typically chosen for TVs and such don't correspond exactly to the peaks of the cones' responses, but to colors that are pretty close and that have cheap available phosphors. And you really can stray pretty far from the actual human visual primaries and still get a good gamut. And non-human eyes may have entirely different primaries--birds have four, for example. --LDC

Red, green and blue are not the peak responses. The wavelengths of the peak responses are given in the color article. You choose red, green and blue light because you get the biggest part of the human color space that way. Red light for instance is lower in frequency than the "red" cone's peak frequency in the eye so that it won't create a response in the "green" cone (the cone's response curves overlap). There is a definite biological reason why red, green and blue light are the additive primaries for human color vision, but it's not the peak responses.AxelBoldt

[edit] Primaries in L*a*b space

On the diagram at color under 'CIE XYZ color space', the colors around the outside of the horseshoe shape (but not the bar that links the two ends) are colours that appear in the rainbow. That is, they can be made of light of a single wavelength. This makes them a bit special, and could be the basis for calling them primary. They cannot be made by mixing any other single-wavelength colors. The colors in the middle (which would include the colors of phosphors used in television) can be made by mixing pure-wavelength light (or colors from the outside of the horseshoe). The colors on the bar that links the two ends of the horseshoe are sometimes called 'imaginary colors', as they don't appear in the rainbow, and there is no single wavelength light of those colors. They must be made by mixing the blue and red wavelengths at either end of the rainbow.

The "primaries" in XYZ space are beyond the range of human vision. In other words, they are purely imaginary. --jacobolus (t) 22:24, 22 April 2007 (UTC)

[edit] Ok for the hundredth time

And you are are very cose to correct but listen carefuly, cause it's confusing: Additive color is not a color space. RGB of given colors can be a color space. So you can say a such and such RGB is a color space which uses the additive color system..yadda yadda So you can say a such and such CMYK is a color space which uses the subtractive color system..yadda yadda

So ya almost got it

I'm getting the page entitled Subtractive color space deleted by the admins, 'cause it's just plain wrong. We willl eventually have a lovely page describing the subtractive color system.

Am I making sense?

It's subtle, but crucial--Dkroll2 02:51, Dec 27, 2004 (UTC)

[edit] Color and Color vision is a simple task to describe.

color

I havent' a clue what ya'll have done to this definition but it's been taken to the far side. Color and Color vision is a simple task to describe. Just do that, I can't believe all the techno mumbo jumbo which belongs somewhere else. I'm saying to delete the visible spectrum or the rods and cones, but red it and imagine you are coming there wanting to know how color works, and maybe link to a section on how to control it/standardize/quantify it. Too much in one place just for a tiny word "color" IMHO Love ya smarties anyway --Dkroll2 06:37, Dec 27, 2004 (UTC)

[edit] Wikiproject Color

I'm looking to start up Wikipedia:WikiProject_Color again. It seems to have been dormant for a while, even though there was a lot of great work and discussion already done. Anyone care to join me? --Laura S 01:31, 19 May 2006 (UTC)

[edit] The term vector basis may be improper

Hello. In the introduction, we have:

If the color space is considered as a vector space, the primary colors can be regarded as a set of basis vectors for that space.

but I think it is not mathematically correct. If the color space is of dimension 3, then any three linearly independent colors would make a set of basis vectors, even if they are not primary colors. Probably primary colors would be better defined has extreme points of a convex set, or perhaps generative vectors of a convex cone. --Bernard 17:36, 22 September 2006 (UTC)

No, basis vectors is exactly right. Any three linearly-independent colors can be called primary colors. There is absolutely nothing special about the primaries in widespread use. --jacobolus (t) 22:26, 22 April 2007 (UTC)
To follow up, no 3 colors can be mixed to produce all other possible colors. In fact, most spectral colors (single wavelength) cannot be produced in a second way. The only way to mix all colors as a combination of three primaries is to make the primaries imaginary, beyond the range of human vision, as in CIE XYZ. --jacobolus (t) 22:28, 22 April 2007 (UTC)
In other words, it's not a vector space. The gamut is a convex set and the area covered by a set of primaries is a convex cone, as he said. 86.5.99.20 12:13, 14 October 2007 (UTC)
Oh, okay. You might be right. I'm realizing I don't have a precise understanding of the mathematical properties of the space of human vision—that is, what the effect is of making e.g. some spectral light source arbitrarily bright. Given that there is indeed some point beyond which additional intensity cannot be detected (or maybe it just fries your eyeballs at that point :), scalar multiplication doesn't necessarily hold for a large enough scalar, which would make us have not a vector space. But anyway, in the vector space of which the gamut of human vision is a subset, any three colors can be considered a bases for the space… so the description in the article is still fine I'd say. --jacobolus (t) 15:38, 14 October 2007 (UTC)
Jacobolus wrote "The only way to mix all colors as a combination of three primaries is to make the primaries imaginary". That's not true. The other way is to allow negative coefficients in the linear combinations. It's a vector space, in theory, if you do not impose gamut limits, and this is what is meant in "If the color space is considered as a vector space". A gamut is then a region in this vector space (probably convex, but not necessarily so). It's important to keep clear the distinctions between mathematical colorimetric, human perception limits, device limits, etc. Within mathematic colorimetry, it's very clear what is meant by vectors, imaginary colors, etc. Dicklyon 17:06, 14 October 2007 (UTC)
Well, we're no longer mixing real lights at the point where some coefficients are negative. :) But right. --jacobolus (t) 22:11, 14 October 2007 (UTC)
True; if you make that restriction to positive coefficients, that's when you get a gamut that doesn't cover all colors. That's still a region in a vector space. Dicklyon 22:52, 14 October 2007 (UTC)

[edit] Gendale?

I believe this is a newly discovered primary color. Shouldn't it be mentioned somewhere on this page?24.234.170.197 02:15, 5 October 2006 (UTC)

Gendale is a joke, isn't it? From what I have seen on the web, it seems to be an impossible color --Bernard 19:10, 9 October 2006 (UTC)

[edit] Primary Colour or Colour?

I found the page by typing 'primary colour' and in the first paragraph it said 'A primary colour or colour'. I found the page again by typing 'primary color' and the introductory paragraph said 'A primary color or color'. Why does it say this?--Jcvamp 13:59, 11 December 2006 (UTC)

Maybe it is some Wikipedian who allowed this to work, but I HAVE NO IDEA HOW THIS IS POSSIBLE. Georgia guy 14:43, 11 December 2006 (UTC)

[edit] B Class in wikiproject color?

This article has no introduction, is full of claims of dubious scientific merit, and has almost no relevant citations. It does not discuss the history of primary colors, or their historical application to paint mixing. It does not show any chromaticity diagrams with labeled primary color gamuts. It does not give the reader a clear understanding of the idea of a primary color, and it does not put that idea in its pre-20th-century historical context. I think I would classify this "start" class. --jacobolus (t) 22:45, 22 April 2007 (UTC)

[edit] Muddy brown

Just a question for the color experts here, and something that might be a nice addition to the article. The article mentions that "in theory" full combinations of saturated cyan, magenta, and yellow should produce black but that they don't. Is this because most light is not precisely white? If this is the case, it might be nice to point that out as the reason why for readers. If that's not the reason, does anyone know what is? —Preceding unsigned comment added by Troped (talk • contribs)

Of the numerous references that repeat this comment, I only found a reason given in one, and it was wrong, so I won't bother quoting it. The problem is that the inks tend to be in layers, and the upper layers will reflect some light before giving the lower layers a chance to absorb it. If yellow is on top the result will be brown, but for other orders it will be some other off-black muddy color. Dicklyon 18:10, 8 June 2007 (UTC)

Also light is very rarely white, but the human brain adjusts to tell the color of something regardless of the light. For example, indoor light bulbs are usually very yellow -- —Preceding unsigned comment added by 209.247.23.35 (talk)

White is not a well-defined color for light. When using incandescent light, the color of the light is usually taken as white, or the illuminant white point, even though this white is yellower than some other whites. So saying "light is very rarely white" is essentially meaningless. Dicklyon 18:27, 19 June 2007 (UTC)

[edit] tetrachromats

Is there any evidence (i.e. actual psychological experiments on birds, neurological arguments, or even speculation from reputable biologists, etc.) that species with four types of cone responses actually have vision which can be modeled in a four-dimensional space, or is this just a speculative extension of the three cone types → three-dimensional color vision that we humans have? I don't notice any cited sources for this claim. If not, I'd like to remove such claims, or at least eliminate the certainty with which they are stated in this article. If so, I'd like to see a better explanation, and some citations. --jacobolus (t) 01:14, 26 June 2007 (UTC)

Also, it should be made clear that the three-dimensional models for trichromatic color are also just rough approximations, based on very strict assumptions. Color vision seems to be much more complex than any simple mathematical models, so this whole article is just a useful abstraction, not necessarily a direct representation of reality. --jacobolus (t) 01:44, 26 June 2007 (UTC)
Okay, actually an academic paper linked from the tetrachromacy article says the following:
One further modeling improvement supposes that the additional photopigment serves two different functions. First, the fourth pigment may possibly be serving as a normal pigment variation that is integrated into a standard three-dimensional structure of metameric classes (thus, heterozygotes with four-photopigment classes expressed are not discernible on the basis of color-matching measures). Second, the fourth pigment may also feed some higher order (probably cortical) mechanisms that take advantage of the signal from the fourth pigment for color discrimination in a way that differs from judging metameric class equivalences. This second possibility is not unlikely since, in other species, wavelength information can be used for various perceptual tasks quite independently from the structure of metameric color codes. That is, color vision and wavelength-dependent behavior can independently coexist in the same animal (e.g., bees exhibit trichromatic color vision exclusively in feeding and in recognition of the hive, while, at the same time, using spectrally narrow-band receptor channels for a variety of other tasks, such as celestial orientation and navigation; see Menzel, 1985, for a discussion). Thus, one might venture the speculation that the present results indicate that the fourth pigment—though it seems to merge with trichromatic equivalence classes of primary codes—is exploited by independent mechanisms that deal with the discrimination of border discontinuity and the like. Such architectural implications very much resemble those from studies on cortical colorblindness, or achromatopsia (Stoerig, 1998; Troscianko et al., 1996).
Which implies to me that the ramifications are not precisely known, and these statements about four-dimensional spaces are speculative, without a rigorous experimental justification. So that should be reflected in the article, I think. --jacobolus (t) 02:48, 26 June 2007 (UTC)
Good idea. I also haven't seen evidence of true tetrachromacy, though I wouldn't be surprised.

[edit] References

I cleaned up a bunch of misinformation, and found refs for most of what remains. Feel free to add more, or call for more citations on questionable info, or add more info. But don't add unsourced info: look it up, please. Dicklyon 06:42, 26 June 2007 (UTC)


[edit] Yellow and Blue make green

If you mix yellow paint with blue (blue, not cyan) paint you get green paint. The subtractive colour model does not account for this (try it, you get black), so why does it happen?

Red, Yellow and Blue are the traditional artistic primary colours, and they don't get a mention here, this is wholly different to the CMYK model. Its all too computer biased here with no basic artistic foundations. —Preceding unsigned comment added by 81.99.38.101 (talk)

I suggest you read this link and this one, and perhaps look at this picture as well. Indeed this article isn't nearly as comprehensive as it should be. You're right that yellow and blue (though usually closer to "cyan" than "blue") paints mix to a rather unsaturated green. I don't think anything in this article contradicts that, however. What happens is that paint mixtures don't go along straight lines in a color space like CIELab or CIECAM02, but along curved paths, in this case bowing out towards the green. To get rich greens though requires using green pigments. See this picture which shows fairly unsaturated mixtures of blue and yellow paints on the top row, as compared to brighter green paints on the bottom row (and obviously the exact effect can't be accurately seen on a computer monitor; the distinction between top and bottom rows would appear if anything more dramatic on paper). --jacobolus (t) 01:11, 31 July 2007 (UTC)
To be clear though, this article should certainly discuss "traditional artistic" colors, and discuss their historical changes as new pigments became cost-effective, etc., and should preferably roughly locate the "Red", "Yellow", and "Blue" intended in a color space like CIELab or similar, so that readers can have a better understanding of which colors specifically are meant by each of these descriptions. --jacobolus (t) 01:29, 31 July 2007 (UTC)

[edit] Secondary Colors are not Primary colors

I thought it was a fairly simple concept that a palette named the "secondary palette" was not, and did not claim to be, limited to primary colors, I also noticed that the palllate at the cited web page does not match the one listed here, so I'll be modifying that section.

Please do not start a revert war, thank you.67.34.196.115 16:55, 15 August 2007 (UTC)

“Primary” colors are a human construct. A “split primary” palette also does not include “perfect primaries” in the eyes of the 18th-19th century color theorists who developed the idea of material trichromacy. By my definition any color which is used in a palette which cannot be mixed from the other colors of that palette is sufficiently “primary”. If you like, we can change this word to something less controversial (controversial in the 19th century perhaps…). Anyway, you still borked the citation format, changed the meaning of the article, and reverted several changes unrelated to the issue you care about. Before reverting again, please get a concensus on this talk page. Thanks. Also, consider making your own user page, so we don't have to refer to you by number. --jacobolus (t) 17:06, 15 August 2007 (UTC)
I've changed the sentence slightly to clarify. --jacobolus (t) 17:14, 15 August 2007 (UTC)

Just because something is a human construct does not make it valid to simply disregard its internal logic, the website your citing does not provide support for the statement its being used as a source for, first off red is not part of the secondary palette explained at the source, secondly the author does not call most of the colors on this palette primaries or even "primaries" the whole point is that it rejects the idea of primary colors altogether. If its that big a deal to keep it here I'll change it in a more conservative manner.

As for consensus so far you and I are the only people whove said anything about it one way or the other, I know becuase I listed RYB here in the first place and I've been watching it, this is a new section and any edits to it are essentially new changes to this page.

Velps 18:04, 15 August 2007 (UTC)

No, but the point is that artists who use “primary colors” as a means of organizing their thoughts about color are oversimplifying, and relying on a model that imposes real costs on colorfulness of “non-primary” hues. Thus some artists instead use 6 (or more) colors, evenly-spaced around a “color wheel”, to reduce those costs. To change the link and wording as you did undermines that message (which is the reason that I originally wrote that sentence as I did). But equally, the problem was that you several times reverted unrelated changes, and damaged the formatting of the page, in your quest to revert to the version that you approved of, even after it had been pointed out. I've made one more fix to the sentence… see if that does it for you. --jacobolus (t) 18:12, 15 August 2007 (UTC)
And note, the RYB color model article as it stands a) is poorly explained, b) contains quite a bit of unsubstantiated nonsense, c) is unsourced, d) has diagrams which obscure as much as they illuminate. It needs to have a solid historical section written, a much more thorough explanation of the gamut which can be made by RYB paints, with some solid diagrams, and a critical review section at the end which explains why it is no longer particularly useful, in light of newer and more perceptually-accurate models. I fixed the summary posted to this page (primary colors) to no longer contain nonsense, but I don't really have the time or energy to fix up the RYB color model page. --jacobolus (t) 18:18, 15 August 2007 (UTC)

I don't see how the validity or invalidity of the concept of primary colors or RYB color space in general has any bearing on the part of this section we're talking about, when I said I listed RYB here, I ment here in this particular article, RYB has historical importance and exists as a concept. In any event I've edited the section in a less severe way which is also supported by the cite hopefully this will be satisfactory for everyone Velps 18:25, 15 August 2007 (UTC)

No. A palette with 6 colors is not 3 “primaries” and 3 “secondaries”. There is absolutely nothing special about three of the colors as opposed to the other three. You'll note that if there was, the three “primaries” according to this palette would then by cyan, yellow, and magenta. I really suggest you read this page before continuing to edit the page. It will hopefully give you a better understanding of so-called “primary” colors. --jacobolus (t) 18:31, 15 August 2007 (UTC)

There is nothing objectively special about them, and while you may, perhaps rightly, feel that all the colors on the secondary palette deserve to be called primaries, they're not, that's why its called the secondary palette. I'm not particulary interested in the scientfic or practical value of RYB with regard to this particular point.

Please keep in mind I'm only calling them notional secondary colors.

I also think you're relying way too much on this handprint website and starting to make an argument rather than convey information in a NPOV non-OR way. Velps 18:58, 15 August 2007 (UTC)

Listen, the point of the sentence is to explain the limitations of relying on primary-color models, which happen to be bad models for a variety of reasons. If you leave out such explanation, the article endorses the ideas that RYB is good for painting, which is most certainly NPOV. Frankly, several more sections should be added to this primary color article, explaining historical development, and more robust criticisms. But until that point, I'd prefer to keep the part that is here both accurate and NPOV. --jacobolus (t) 19:19, 15 August 2007 (UTC)

Whether ot not RYB is "good" or "bad" is a personal preference and a value judgement, the article explains the limitations of RYB fairly thouroghly as is without the ideosyncratic definition of primary colors and the single source rant against the concept of primary colors Velps 19:51, 15 August 2007 (UTC)

No, the model of color (so-called material trichromacy) is empirically wrong, and quite visibly deficient. As for the particular choice of paints or inks, that is certainly personal preference, but choices other than RYB (particularly those using more than 3 colors) lead to wider gamuts (note: this is not a matter of opinion). --jacobolus (t) 00:27, 17 August 2007 (UTC)
What is "material trichromacy"? Does it appear anywhere other than handprint.com? Dicklyon 01:30, 17 August 2007 (UTC)
Yeah, perhaps another term should be used. I think it's a decent name to give the idea that all colors can be created by combining three "primaries", but that should probably instead be explained explicitly. I'm not sure if it appears elsewhere. --jacobolus (t) 02:10, 17 August 2007 (UTC)
I've removed the term. I think it's actually explained fine without it. --jacobolus (t) 02:19, 17 August 2007 (UTC)

There is no person or body with the authority to declare RYB "wrong", its based on tradition, many people still use and teach red yellow and blue as primary colors, and even if there was such a person or group CMY is also based on three pigments so "material trichromacy" its not a problem particular to RYB.

Handprint.com is the only result for a google search on "material trichromacy" the websitre author doesn't appear to quoting it from anywhere that I could find I believe its a personal coinage.

Furthermore I couldn't find any other websites independently detailing the "secondary palette" mentioned at handprint.com nor does the author clearly state that this particular palette is used by "many" other painters.

On top of that the description of the secondary palette given here does not match that at the referenced website, which does not include red. Velps 01:48, 17 August 2007 (UTC)

a) Anyone can quite clearly see that red, yellow, and blue paints cannot mix all colors. No authority is required to make such a declaration. b) That's fine, it's not necessary to list the specific colors which might be used in a broader color. c) Please stop adding "notional secondary color". It's meaningless as far as I can tell. --jacobolus (t) 02:10, 17 August 2007 (UTC)
Is this version finally suitable for you, Velps? --jacobolus (t) 02:19, 17 August 2007 (UTC)
Finally, some sense on the colour pages. I wonder if it's worth mentioning that you'd need eight starting colors in opaque paint to cover the same gamut that three could with light eg. two points in a cube produce a colour along a line between the points depending on concentration. I suppose you could count the paper as one of the starting colours. Neodymion 08:20, 30 September 2007 (UTC)

Whether or not RYB can mix all visible colors is a moot point with regard to whats been under discussion, I'm not aware of any set of three additive colors that can do that. I still think its less than ideal that we're relying quite so heavily on what is essentially a very nicely put together personal website for citation, but the content of the article itself looks fine. Velps 17:22, 17 August 2007 (UTC)

Here's a book with good stuff on RYB system. – Dicklyon 18:01, 17 August 2007 (UTC)


[edit] Colour!

The English invented English if your going to speak it do it right and stop being awkward, its colour. how would you feel if candians insisted in publishing stuff allover the net that spelt burger "bergar" just because they felt like it? Fists 10:55, 17 October 2007 (UTC)

I've reverted your changes to this talk page. Please don't change others' comments: they are a historical record. --jacobolus (t) 03:30, 18 October 2007 (UTC)
Also, please take a look at WP:ENGVAR. --jacobolus (t) 03:32, 18 October 2007 (UTC)