What can we do with a color point in a 3D space?
As such it corresponds to a unique color. How to do something with it ?
One point, if he does not have dimension, nevertheless has the quality of being an attractor, a vanishing point, a center of gravity, a destination.
It seems somewhat interesting to consider it as the center of a sphere and consider the colors located on the surface of this one. More the chosen radius will be smaller and more these colors will be close to its center.
For example, for red color we get the colors of Figure 1 a. All these colors are on the envelope of the sphere whose center is the red of the horizontal bar below. They are therefore located at a same distance from this color.
This approach illustrates the fact that with a geometric approach of colors we consider that relations between they are based on distances separating them or bringing them together according to whether they are large or small. The random arrangement of colors of Figure 1,b composed with fifty color squares, seems homogeneous because the colors used have a single common feature: to be at the same distance from a particular red.
The richness of the spatial approach of three-dimensional colors manifests now. Instead of thinking in terms of monochromatic or analog chord with a color wheel and then to look for variations of value and saturation that appear to agree, the use of Euclidian distance makes it possible to obtain directly colors that are related in their three dimensions .