Design & UX
Article

Red, Yellow, and Blue, or CMYK

By Jason Beaird

Following straight on from the last article in this series on color, Color Theory 101, we’re now going to take a better look at the RGB and CMYK color wheels.

I’m constantly amazed by the lack of respect that exists for the red, yellow, and blue primary color wheel. I’ve heard people call it invalid, archaic, and a kindergarten tool. It’s true that the red, yellow, and blue color wheel is not a scientifically accurate model of the perception of light. Many people want to eliminate the red, yellow, and blue color wheel from art curricula, and establish the CMYK (cyan, magenta, yellow, and black) color wheel, shown in Figure 1, “The CMYK color wheel”, as the universal color model. Note that the secondary colors in the CMYK color wheel are red, green, and blue, meaning that we could use the CMYK to illustrate both additive (using light) and subtractive (on paper) color.

Fig. 2, The CMYK color wheel
Fig. 1, “The CMYK color wheel”

To illustrate the reasoning behind the push to move to CMYK, I’ve used gouache paints, which are basically watercolors that come in a tube. When mixed with water, they are fairly translucent and produce the colors you would expect to see on the modern CMYK color wheel, as Figure 2, “Playing with CMY gouache paints” shows. Magenta and yellow mix to produce nice shades of orangey reds, while cyan and yellow mix to produce green and minty tones. This is how CMYK printing works. The inks are translucent and the overlap between them (along with the use of black—don’t forget good ol’ K) gives us most of the colors we can see on an additive, light-emitting monitor or TV. As the famous TV painting instructor Bob Ross might have said, “That’s a happy little color model.”

Fig. 1, Playing with CMY gouache paints
Fig. 2, “Playing with CMY gouache paints” — click for a hi-resolution scan.

Wait! What’s that purple splodge? Yes, equal amounts of cyan and magenta form a violet or purple, instead of the pure blue suggested by the CMYK color wheel. Numerous anomalies like this crop up when we mix opaque pigments. Basically, if your paint is so thick that you’re unable to see the white paper or canvas on which you’re painting, the concepts of a CMYK color wheel start to fail. In this regard, the traditional red, yellow, and blue color wheel developed by Goethe, Itten, and others over the last four centuries or so is a much better model.

But we’re using pixels, not paint! The reason many digital artists still keep a red, yellow, and blue color wheel handy is because the color schemes and concepts of traditional color theory are based on that model. As we’ll see shortly, the relationships between colors are largely determined by their relative positions on the color wheel. But those positions differ depending on the wheel; for instance, on the traditional color wheel, red and green are opposite, whereas on the CMYK wheel, cyan is opposite red. We can’t simply shift the red and blue around the color wheel and call it a day. Because of this, the color schemes that I’ll be discussing in the next few articles are based on the red, yellow, and blue color model.

There are flaws to be found in both color wheel models, and complementary colors are a prime example. But what’s really going to bake your noodle is when I tell you that there is no color wheel that can fully describe the complexities of the way in which we perceive color from light. Even though I design mostly for the Web—a medium that’s displayed in RGB—I still use red, yellow, and blue as the basis for my color selections. I believe that color combinations created using the red, yellow, and blue color wheel are more aesthetically pleasing, and that good design is about aesthetics. Therefore, I’m going to present color theory as I learned it in my sophomore design fundamentals class in college: from the traditional red, yellow, and blue color wheel.

The Principles of Beautiful Web Design

This article is from Jason Beaird’s The Principles of Beautiful Web Design book (second edition is out now!). Be sure to lookout for further articles from the book here on Design Festival.

  • Agelana

    I cant agree more with you. While in college we had the big task of making a giant color cube. We had to create around 500 colors using only yellow, blue and red. It was an amazing job, and learned to see colors within colors.

  • Choupatte

    As I understand it, RYB is for reflected light and RGB is for transmitted light. I painted with oils and acrylics for years before computers were common objects and RYB was the standard. I had to change the way I thought when I went digital and found that RGB was standard.
    Before whenever I mixed yellow and blue paint I got green, red and blue purple, red and yellow orange. It doesn’t work like that with light (screen pixels), I had to learn all over again.

  • PaddyMac

    As an artist, could I add a few clarifications:
    “I’ve used gouache paints, which are basically watercolors that come in a tube.”

    That’s not correct. Professional watercolors almost always come in a tube – you must be shopping at the office supply store!

    Gouache is watercolor with added chalk, which makes it more opaque. Some pigments are naturally more transparent (quinacridone etc) and some pigments are more opaque (cadmium, etc), but as a general rule, Gouache will also be more opaque than the same pigment in Watercolor due to the nature of the medium.

    And just to clarify, most artist’s don’t use a simple color red/yellow/blue color palette. You will get muddy colors unless you start thinking of it as warm/cool versions of RYB. i.e., warm red/cool red, warm yellow/cool yellow, warm blue/cool blue. So, if you want to create pure mixes of colors, say a nice bright spring green, you mix cool yellow (lemon) with cool blue (greenish blue). If you mix a warm golden yellow with a warm purply-blue, you will get a muddy olive green.

    • PaddyMac

      I might also add that a print designer, I find CMYK useful for specifying flat color. But when picking colors in Photoshop, I prefer to work in HSB, as Hue, Saturation and Brightness/Lightness is a very logical way to work.

  • Agelana
  • Kurt Lownertz

    I believe it is essential to distinguish between how colours are perceived, and how paint, ink or light is used to produce that perception. If the perceived colour is important, you should consider the NCS (Natural Colour System) colour space, which is based purely on how humans perceive colours and the difference between them. Then the NCS colour code can be mapped to other systems used for production, and you don’t have to argue about which of those systems/colour wheels suits both purposes best! You can read more at http://www.ncscolour.com/

  • Francis

    An interesting theory that covers these subjects is the Opponent process
    http://en.wikipedia.org/wiki/Opponent_process
    It has 4 (not 3!) primary colors: red, green, blue, and yellow.
    It is based on the notion that red/green and blue/yellow are opponents, because there is no such thing as reddish green or bluish yellow (hence the surprise every kid gets when mixing these 2 colors, and obtaining a third, eg green).
    According to this theory, the 3 colors from the eye cone cells get processed into 4 inside the brain.

  • Eyevaan

    this is great. I have wondered how valid the RYB model is to people working/growing up with digital color. I was trained in the visual space (conventionally) in RYB with white/black for tone, then the uneasy transition into CMYK [good enough – except for the lack of range of color] then Frodoshop overtakes Scitex/Hell (which were still CMYK unless you were outside electronic pre-press 1996) and now we are firmly planted into RGB (changing a single letter meant so much (so much grief as you tried to print R – G – B (HA!)) which as far as I can tell no one who is able to really talk color theory and the interaction of color and light (refraction and reflection) outside of a physics lab. Anyone confused – yet? You should be (say “stochastic screening” – oh gosh) and I wonder if we’ve learned anything at all along the way or are we still just amused by our digital watches?

  • Manoj jose

    sir,

    We are usually using Spectrophotometer for the color measurement. Here they are using CIE LAB as a color space for the color mapping in this instrument.
    Why we are not using CMYK color space.

    Thanking you.
    Manoj Jose

Recommended

Learn Coding Online
Learn Web Development

Start learning web development and design for free with SitePoint Premium!

Get the latest in Design, once a week, for free.