Talk:Subtractive color

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Article Grading: The following comments were left by the quality and importance raters: (edit · refresh) Much of the data for subtractive color is wrong. first of all, the CMYK scheme is for additive color. The true primaries of subtractive color and of the world of art are, red, yellow, and blue, and they aren't "secondaries" as the article stated. Light mixing is additive, such as say TV screens. And the light mixers use the printer's CMYK colors for their additive colors. Artists don't use these. Artists use the subtractive red, yellow, blue, as stated. The secondaries, so-called, are as follows: r + Y = orange, the opposite of blue; y + b = green, the opposite of red; and R+ b = purple (violet), the opposite of yellow. That is all, except for the distinction that, purple<>violet. Violet is actually (usually) a red-purple, but many different schemes have been devised over the years, some of which call purple, violet. But actual purple is the opposite of yellow, and nothing else. Because the colors are wrong, some of the colored diagrams are wrong as well. The RGB scheme is also used for additive colors, this is true, but never for subtractive. CMYK is never used for subtractive artist's colors. What the article(s) don't distinguish, is that artists use entirely different taxonomies and schemes than do either printers/reprographics, or screens/TVs/CRTs. That seems to be the MOST important item the articles have failed to disinguish. Furthermore, the conventions for additive are mostly conventions only, whereas the artists' standards are optical. Example: Y + B = G, but green is never primary (for subtractive color). FYI

Contents 1 Yikes, Wikipedia sure has gone downhill 2 Subtractive? 3 Silver and Gold aren't "colors" per se. 4 Lack of information? 5 Article too technical

[edit] Yikes, Wikipedia sure has gone downhill

Yikes, I've not seen these definitions for 2 years. They have been through an evolution to perfection through the words of many people (in the fields of color science, etc.) when I left in 2004. Now the pages on color terms have come full circle back to horrible, confusing, bad grammar, inorrect info, info in the wrong place. I gotta give up. Good luck to you all, I'm sure you will all figure it out and the pages relating to color will be good again someday...until the next generation of "Wiki's" comes along... ha ha.

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It's not "Subtractive color space" It's just Subtractive color--[[User:Dkroll2|Dkroll2]] 08:38, Dec 24, 2004 (UTC)

Where is a description of the attention needed? Notinasnaid 16:34, 26 Dec 2004 (UTC)

[edit] Subtractive?

It's logically multiplicative colour, isn't it? After all, the proportion of light that one filter ir pigment layer lets through is multiplied by the proportion of light that another filter lets through. —Ashley Y 23:40, 2005 Jun 2 (UTC)

"Subtractive" because the object that you view only subtracts light; the opposite, additive color, is used where the object that you view adds light. Notinasnaid 12:41, 3 Jun 2005 (UTC)

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From the article: "except the imperfect system resulting from mixing real pigments, something that is very confusing nowadays." Could this be explained or a link provided that does explain it? How is this confusing and how is it neither additive nor subtractive? Threepounds 06:44, 8 December 2005 (UTC)

I have to agree. I've deleted it. If this really is outside additive/subtractive color that is both interesting and useful, but it isn't really either unless it is explained. Notinasnaid 09:44, 8 December 2005 (UTC)

It seems to me that mixing oil paints is mathematically equivalent to adding the RGB values in the proportions mixed. So if I start with green paint and add white, it gets brighter, but if I add black it gets darker, so is this additive or subtractive? Neodymion 04:50, 20 September 2006 (UTC) Actually, it seems the Kubelka-Munk Theory is the actual science for this link title but doesn't appear to apply to translucent things like inks. Neodymion 10:57, 1 October 2006 (UTC)

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It seemed necessary for me to extend this article with "For those who want to know more ..." section and an image of layers of coloured glass. As I work on Faculty of Graphic Arts, University of Zagreb, I may be able to get expert opinions on the subject from Department chiefs. I currently work on a project in enhancing of teaching material in this area (reproduction of photography department). Somewhere it should be said about use of actual pigments. Although I might agree that my wording on the subject may not be the luckiest.

I have an additional picture that is three-dimensional and may catch the eye, for other pages. This subject is IMHO the oprotunity to visually enhance Wikipedia, isn't it? If you have an idea of simple animation showing better how this color system works, I may be able to do it in POV-Ray, as this could fit into my project. Mtodorov 69 22:17, 24 February 2006 (UTC)

[edit] Silver and Gold aren't "colors" per se.

Ideas For your point you are trying to make, use monitor green (vivid chartruse you see on a computer monitor.) And make 2 images that domonstrate how the green turns to deep evergreen in CMYK. Or read color printing and add to that.

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[edit] Lack of information?

I'm curious why no one has yet to mention the fact that colors are multiplied. If you want to get all upity (not a real word, I know) you could say that it's "subtractive color" because there is less light than when you started, and I'll buy that for the title of the page, however there is no good reason why we shouldn't explain how light is multiplied, not subtracted.

For those of you who don't understand it, there is one big problem with subtractive color (other than the fact that you can visibly see that it's being multiplied, not subtracted), and that is negative color. There is no such thing as negative color, yet if you subtracted one color from another it seems like you could produce negative color very easily.

Light is measured in values between 0 and 1, including both 0 and 1. 0 is black and 1 is white. When you multiply two decimal numbers less than 1 you get a smaller number, which is why when you multiply two pigments together you get a darker color.

For example, if you combine magenta (RGB decimal values 1,0,1) and yellow (RGB decimal values 1,1,0) then you multiply each of their values. 1 * 1 = 1, so the R decimal value is 1. 0 * 1 = 0, so the G decimal value is 0. 1 * 0 = 0, so the B decimal value is 0. Thus, when you multiply magenta and yellow you get Red (RGB decimal value 1,0,0).

This needs to be explained in detail by someone at some point.

I agree with the principle of this, although the details are a bit off. Light is not measured in values in the range [0,1] since there is no upper limit on brightness, but it's a good model for a filter. It might be more useful to think of a grey filter that reduces the light by 0.5. Two of these will reduce it to 0.25 and so on. A pure cyan filter stops nearly all the red light so it's harder to see the difference between using one or two of them. It's less easy to see with ink since there's a limit to how much ink you can put on one spot. Neodymion 04:34, 20 September 2006 (UTC)

Now I have to disagree. When talking about color, RGB (light) values are indeed measured in the range 0 to 1. See RGB color space and other articles about RGB. I understand what you're saying about an upper limit on brightness, but that hasn't stopped color scientists. Notinasnaid 08:06, 20 September 2006 (UTC)

But you agree with the principle? It seems rather important to get the science right in an encyclopedia. I would support creating a new article 'Color Mixing', especially since everything else I've seen on the net claims subtraction (and half of them still use RYB instead of CMY).Neodymion 06:43, 30 September 2006 (UTC)

'Color' is spelt incorrectly. It's correct spelling is 'colour'.

[edit] Article too technical

This article spends too much time focusing on printing, and does not spend enough time really fleshing out the details of subtractive color. This article needs to be rewritten for a more general audience, and quite a bit of the content here needs to be moved to a more appropriate article. This article is about subtractive color, and nothing else. Stack 00:00, 15 March 2007 (UTC)