Vivid COLORS and Dull COLORS
Saturation varies horizontally

04-02-01

Going back to Yellow, 
how do you compare the Yellows 
of a lemon and a pear?

You might say the Yellow 
of  the lemon is brighter, 
but more to the point in this case, 
it is vivid, while the Yellow of 
the pear is dull.

04-02-02

This is an other big difference, but this time one of color Saturation or vividness. 
This attribute is completely separate from those of both Hue and Lightness.

04-02-03

04-02-04

 
SATURATION or
CHROMA
varies horizontally