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Related: Why is there a difference between additive and subtractive trichromatic color theories?

RGB is additive color and CMY(K) is subtractive.

If you built an electronic screen with CMY subpixels, you'd be able to mix colors additively. Cyan + Magenta = Blue, Cyan + Yellow = green, and Magenta + Yellow = Red. Can CMY be additive and RGB be subtractive?

A photo composed of only Cyan, Magenta, and Yellow pixels.

The photo is composed of only Cyan, Magenta, and Yellow pixels (before Stack Exchange's image compression). It appears pixelated/jittered, but a real CMY display would properly reproduce the colors.

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closed as unclear what you're asking by Kyle Kanos, Jon Custer, Sebastian Riese, glS, Cosmas Zachos Jul 11 '18 at 15:55

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ At first, it seems highly unintuitively what you describe in your first claim, that one can mix CMY pixels, just in the same way one can do with RGB. Is that a personal experience you have made, your is it something you just assume? Or am I stupid and don't know something that everybody else knows? $\endgroup$ – Quantumwhisp Jul 1 '18 at 19:11
  • $\begingroup$ I'm not an expert in the human visual system, but I think you should definitely document the claim "If you built a computer screen with CMY subpixels, you'd be able to mix colors additively." if you can, because my first reaction is that this is not the case. $\endgroup$ – dmckee Jul 1 '18 at 20:20
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    $\begingroup$ Without a comparison to the original we don't learn much, though I notice there are no highly saturated reds or blues in the image you've chosen (or if there were they are not properly represented). $\endgroup$ – dmckee Jul 2 '18 at 0:04
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    $\begingroup$ The Wikipedia article on colour gamut has some relevant information. $\endgroup$ – PM 2Ring Jul 2 '18 at 0:27
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    $\begingroup$ @the_photon It can't be that simple. If you view a trio of bright CMY-filtered lights at a distance, certainly they won't subtract to appear black. Also, the question is then exactly what cyan, magenta and yellow or red, green and blue you choose as your primaries. These can and do vary and the color system still "works." So, why wouldn't you be able to vary RGB "all the way" to its complement of CMY, or vice-versa? $\endgroup$ – Maxpm Oct 18 '18 at 8:32
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No additive CMYK doesn't cover enough of the chromaticity diagram to replace RGB. In fact RGB doesn't do a great job of showing all the visible colours.

cie diagram

The available CMYK colours are those inside the 5 sided magenta box. You can of course make a picture using additive CMYK which only contained shades inside that box.

(sorry SO won't upload the full size svg image)

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    $\begingroup$ FWIW, you can put your SVG onto GitHub as a Gist, and the preview will display it. Eg, this At least, it does on the desktop view, but sadly not on the mobile. $\endgroup$ – PM 2Ring Jul 2 '18 at 1:42

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