31 March 2009

Colors In Hyperspace

2001.From color wheels to the Wilcox Bias Wheel we've gotten theoretical. Now get ready to go seriously abstruse.

Just as the inhabitants of Flatland know there is a third dimension above the two-dimensional world they live in but can't comprehend, the world of the flat 2-D color wheel tells just half of the story. There is a way to arrange color values along a three-dimensional rationale.

Color can be quantified three ways:
  1. Every color has a hue, or its essential color. When we say Yellow, we are talking hue.
  2. Every color is also modified by its value. This is how light or dark the color is. A simple value scale is a gradient from black to white through tones of gray. Art students typically are asked to create 10-step value scales as an exercise.
  3. And, every color has a chroma. This is how "colorful" your color is, how yellow your yellow is; when artists speak of saturation, this is what they're saying The most colorful color is, for instance, that yellowest yellow – the least colorful color is gray – if you take all the yellow out of your yellow. Colors with low key chroma are dull and gray, and this is the same for all colors.
Just there exist three axes we can use to construct a 3-D conception of colors and how they relate to each other.

We've gone to the next level; welcome to color hyperspace.

Originally, color theorist Otto Runge (ca 1810) concieved of a sphere an idea that was forwarded by Johannes Itten later, perhaps reasoning via the love of the human mind for symmetrical depictions of natural things. Ostwald, even later, depicted the color space as a double-cone.

The flaw in this reasoning has to do with human perception. When plotted on a 3-D solid, one would assume that the pure colors would line up about the equator of the solid, and this is not the case:
The problem with both the sphere and the symmetrical cone conceptions of colour space is that, as we have just seen, different hues reach their maximum chroma at different tonal levels.  Putting all of the pure colours on the equator of the solid ensures that the vertical dimension does not represent lightness. Consequently neither the Runge-Itten sphere nor the Ostwald double cone is a true hue-chroma-lightness space. If the vertical dimension of the solid is to represent lightness, then we need in some way to tilt the colour wheel through space, so that yellow occupies a high position opposite light grey and blue occupies a low position opposite dark grey.

So if your axis, your value scale, is to work, you also have to respect that the purest colors will not occur at the same values. The symetrical solid will not work truly.

In order to make a solid work, an irregular solid will work. Purest blue has a lower value than purest yellow, so the solution turned out (through the work of various color theorists staring ca 1880, culminating in the work of a certain Albert Henry Munsell in the early 20th) to be a skewed double cone, something we call today the Munsell Color Solid. Above and to the right should be a image from Wikipedia giving the basics (and click here to see the big version or click on the illustration itself). Here, from David Briggs article at HueValueChroma The Dimensions Of Color is an illustration that really spoke to me about it. You can probably find others yourself with teh Google:

Illustration copyright David Briggs, included for illustration only.
Creator retains full rights to this illustration.

When smoothed out, it looks like a squished globe. The plot in the lower right there really makes the concept come up. As you can see, from up to down everything gets darker. On the lower right of the 3-D display, note that the blue there is the bluest blue; on the upper left, they yellowest yellow is of a significantly higher value. The system is consistent, respects its own rules, and works.

It is not necessarily likely that you'll use the Munsell solid directly, but like the most abstruse philosophy, the thinking behind is presumably underlies the color theory that the layman is most familiar with. It is data that will probably help you a little bit in deciding on using colors based on the qualities you actually see them with.

Here's a few links for you:

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