12-color CMY/RGB Color Wheel

color wheel

color wheel - cmy|rgb color wheel
12-color CMY/RGB color wheel
Represented in RGB colorspace
Thesis

Do yellow and blue make green?

As many a frustrated kindergartener find out, not exactly. The truth of the physical world does not always conform so neatly to our models, no matter how entrenched those ideas might be.

This essay will explore one of these models, the artist’s color wheel — taught through centuries in the atelier as fact. But like many things passed down through rote tradition, this model too could use a bit of freshening up — updated with some scientific understanding coming out of the brain science of neurology.

The traditional color wheel is not wrong, just missing something important, a deficiency for which we cannot be blamed, just coming from our natural blind spot. The result will reflect a model closer to how the phyiscal world operates: the CMY/RGB color wheel — a tool for analyzing color hue, value and balance among colors, and a more contemporary judgement of color opposition (complements) than the traditional color wheel.

That’s a bold claim. So, how do we get there?

Background

Some contemporary artists are beginning to challenge the traditional artists’ color wheel, particularly in light of their own personal experience with commercial printing processes. 1 Having seen how it works on the press, they are forced to reconcile this understanding of color as it relates to the traditional artist color wheel they’ve been taught in art school. Exploring these results also begins to address the challenges presented by the limitation of pigments themselves — more specifically, the constituent metals and chemicals that give pigment its color.

The goal, then, is to create a more accurate color wheel theory.2

The Argument for Something New
Traditional Color Wheel

Farbkreis - Traditional Color Wheel
Farbkreis by Johannes Itten, 1961
Based on the traditional color wheel
By Zeichner: Malte Ahrens [Public domain], via Wikimedia Commons

Painting itself has changed over time with the changes in perceptions brought by scientific understanding. Think of the Impressionists and their new way perceiving light in a scene. Have you noticed how before the paintings of the Impressionists, outdoor scenes look, well, like they are happening inside somewhere?

old painting
Italianate Landscape with an Artist Sketching from Nature by Jan Dirksz Both, 1618/1622–1652
[Public domain], via PublicDomainFiles.com

By shifting their perception and taking the easel outside, the Impressionists discovered new perspectives on how light appears on the surface of objects. And after they did that, the old ways of doing things, while respected, just could not keep up with how we “see” reality.

The traditional color wheel, too, is hundreds of years old. It was taught in the studios of the masters, and that is probably why it is still being taught in art school today — sometimes as a historical foundation, but too often as canon. Yet the color wheel itself, like perceptions of light in a scene when observed at different times of the day, must too yield to a more contemporary understanding of how the human eye perceives what we call color.

What is color?

Visual “colors,” as we understand them, are not physical objects on a rainbow per se, but are actually created in our minds as an interpretation of the wavelengths perceived by the photoreceptor cells of the eye. The majority of these wavelengths are frequencies mixed “out there” in the world from two primary sources, reflective and transmissive light.

  Reflective Light Transmissive Light
   ☇☇ ☼ ☼ ➙ 
Color Model subtractive additive
Color Primaries cyan, magenta and yellow
(CMY)
red, green and blue
(RGB)
Use Cases inks on paper;
painting on canvas
projection on screen;
images on a computer monitor


Reflective light refers to the aggregate of wavelengths filtered from a light source first bouncing off an object before getting to your eye, like the color represented in a leaf. Transmissive light, on the other hand, is the wavelength of electromagnetic energy emitted by the source light itself, like a candle flame.

Reflective light follows the subtractive color model: source light (like white sunlight) comes in contact with the particles of an object (in this example, a leaf) and some of the wavelengths are absorbed — or subtracted — by the molecular structure of the chlorophyll. The unabsorbed wavelengths are reflected back into the world containing only the frequencies of the visible color that reaches your eye, in this case a shade of green. The reflective or subtractive paradigm is in play when you look at a painting made of pigments: the molecular structures of the various metals in the pigments are absorbing source light and reflecting back the resulting frequencies.

Transmissive light, however, follows the additive color model: that is, the source light itself emerges from the black nothingness by combining — or adding — color frequencies in proportion to the aggregate of the resulting color, in the case of a candle flame, something like a red-orange-yellow. The brain interprets the frequency of this electromagnetic energy and assigns the color associated with that wavelength. The transmissive or additive model is in operation when you look at an image on a computer monitor: electromagnetic source energy is created in the hardware, and the projected light is received in the eye.

The Curiousness of Magenta

Wavelength or frequency itself is not color, even in the so-called visible spectrum. Instead, the mind assigns a symbol to represent the wavelength in your brain. That symbol is interpreted as color. The wavelengths received in the retina are interpreted by the brain, and the brain “shows you” color. That is the structure of our world — it is actually all in our heads.

In fact, when the mind does not have a symbol to associate with the wavelength, it just makes one up. A classic example of this is the color magenta. Magenta is not a really color. It is an extra-spectral (meaning, not on the spectrum) “substitute” for a wavelength that the mind thinks should be there, but that does not actually exist in the visible light spectrum. It is not on the rainbow. It is created entirely in the mind.3

the color magenta
Magenta.
Can you see this?
OK, then, where is it in the spectrum?

rainbow
Visible light spectrum experiment:
prisms, electromagnetic spectrum, wavelengths 380 to 750 nm, 790–400 terahertz
via davidsancar
A Contemporary Color Wheel

While it is important to keep this phenomenon in mind (and the metaphysical ramifications of making things up that are not there), for right now, for us artists, the important part of the formula is that magenta “exists”. It is the missing piece of the so-called color spectrum that the traditional color wheel has not taken into account. A more contemporary color wheel, however, does take the weirdness of magenta into account. Magenta is, in fact, the new twist — an anchor of a new model that reconciles the two paradigms of color and wavelength. A model that unifies the common attributes between the additive and subtractive.

And, interestingly, it is done like this:

RGB illumination
By en:User:Bb3cxv [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

The outer colors of the projection are the three primary colors of the additive color model: red, green and blue (RGB). As transmissive attributes of color, these primaries are used in contemporary projection techniques (such as television and computer monitors) from a black-screen source to produce the illusion of the full color spectrum through in-retina visual mixing: all colors “seen” are actually proportional amounts of red, green and blue to simulate the other colors (orange, purple, etc).

As seen in the image above, when the RGB primaries are projected on a white screen, an interesting thing happens: the secondary colors produced by the projection are cyan, magenta and yellow. And, interestingly, these are exactly the three primary colors 4 of the subtractive color model. That is, the CMY of the CMYK Pantone chart (K being black) used in commercial printing processes. CMY are the primary colors of inkjet and process printing, built on the foundations of color science outlined by James Clerk Maxwell in 1861. And as graphic designers know, CMY is a much better arbiter of true color mixing than the traditional primary colors of red, blue and yellow. CMY produces more accurate and predictable color mixing results with inks on white paper.

Therefore, our more contemporary visual color wheel could have a foundation in this overlap. A new color wheel can be constructed from this resultant pattern of the two models combined, with each primary taking its place on an equidistant spot on the wheel. And, to complete the circuit, the secondary colors are created by the visual mixing of the six primary colors, in equal proportion, filling in the remaining six spaces of a 12-slice pie.

The CMY/RBG Color Wheel

These files were created in the CMYK colorspace for printing on a CMYK printer, therefore the RGB files are the result of export from CMYK. This may create technical issues in RGB, depending on your usage. 5   If you require accurate RGB representation, it is recommended to construct your color wheel originating within the RGB gamut.

These colors are machine color. For pigment equivalents, see the color mixing chart.

for RGB uses color wheel - rgb
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for RGB uses color grid - rgb
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for CMY(K) uses color wheel - rgb
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for CMY(K) uses color grid - rgb
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Application for Artists

The 12-color CMY/RGB color wheel (and its correlating grid) represents a valid visual model of color for the purposes of studying hue, value and balance. It also improves upon the traditional artists’ color wheel in terms of visual color complements. However, in practice, it is deficient in determining a color’s mixing attributes (complementary or otherwise).6 That’s because a color’s visual complement is actually different than its mixing complement: the material substance of pigment (color created by reflection of light) is not the substance of light itself 7 (see also The Argument, above). And that notion is also a departure from the traditional idea that an artists’ color wheel can tell you both the visual and mixing complements of the colors represented in one wheel. That is not the case, as many frustrated kindergartners find out: yellow and blue pigments do not make green.

The formation of an accurate mixing regime, however, is a subject for another topic. But, to get a primer on this idea, refer to the color mixing experiments of Lascuax Sirius acrylic paints.


References

1 Naismith, Scott (2012). "Colour Theory: The Truth About The Colour Wheel". youtube.com. 2012-02-18. Retrieved 2015-12-14.

2 Jusko, Don (2005). The Real Color Wheel. Earliest version 2005-07-25. Last modified 2016-06-12. Retrieved 2016-04-04.

3 Mould, Steve (2009). The Curious Case of Magenta. 2009-10-23. Retrieved 2015-12-14.

4 Because the mind assigns color based on wavelength — and all wavelengths are equal on the spectrum of frequency — it has been argued that the concept of “primary color” is really just an arbitrary notion outside an economic, mathematical or technological need to minimize the number of components required to produce all other colors. For more information, refer to:

MacEvoy, Bruce (2006). Imaginary or Imperfect Primaries: Do Primary Colors Exist? Retrieved 2015-12-14.

5 It has been my experience that when you convert colors from RGB to CMYK, you cannot convert back an retain the original RGB hues of your image. Likewise, when exporting from CMYK to RGB will not create the exact RGB equivalent. For more information about the RGB vs. CMYK colorspace, refer to:

Gendelman, Vladimir (2013). RGB vs CMYK vs PMS: Deciphering Design’s Confusing Color Jargon. 2013-07-19. Retrieved 2015-12-14.

Seeley, Justin (2012). "RGB vs. CMYK". lynda.com. 2012-07-05. Retrieved 2015-12-14.

Convert image from RGB to CMYK and back to RGB . 2015-01-15. Retrieved 2015-12-14.

6 The traditional artists’ color wheel is also incomplete in this regard, contributing to the frustration of many beginning artists. (Yellow and blue do not make green).

7 MacEvoy, Bruce (2006). An Artists’s Color Wheel. Retrieved 2015-12-14.

last updated December 14, 2015