B2c) Hard and Soft Color Changes
Artists have traditionally used color wheels to organize uses of color. When manipulating multiple light sources that make additive mixtures, a color wheel can mimic the CIE chromaticity diagram as shown.
If six color sources are used, their chromatic combinations are seen as gamuts of color on the chromaticity diagram. All possible gamuts are shown in the diagram below.
For an applet explaining the CIE chromaticity diagram and gamuts, visit: www.cs.rit.edu/~ncs/color/a_chroma.html .
Hard changes occur between complementary or split complementary colors.
Cross-fading these colors moves through white or near-white due to additive mixing. The change is "hard" because the afterimage of the first color strongly
influences the second color unless the change is very slow.
Soft changes occur between adjacent colors. A spectrum rotation around the color wheel consists of soft changes through the entire range of colors.
B2d) Parallel and Opposite Motion