There is another reason why imaginary color is an appropriate tool for visualizing fields. You may be surprised to hear this, but the colors that we perceive in nature are also imaginary; they exist only in our minds. In nature there are no colors - only light waves of various frequencies. Even the vivid colors of a rainbow are not really there; the rainbow is created by water droplets that reflect light of different frequencies through different angles. It is in our brain, and only in our brain, that these signals are magically {and I do mean magically} translated into a perception of color.
( Rodney A. Brooks )
[ Fields of Color: The theory ]
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