The way light is split when passed through a glass/crystal prism, giving the eye a spectrum of different beams of light, shaded into colours. These colours can then be manipulated, even though they melt into one beam on passing through the prism.
The resultant manipulation causes an infinite amount of shades, each one named, e.g. orange mixed to, say, vermilion.
Objects that absorb every part of the spectrum of light except the one the object then reflects, e.g. red, blue, but reflects any particular shade of green.
Tried my best here.
What is the biggest book you have read?