Colors

There are two groups of colors:

- a standard set of fixed, named colors that are always defined.
  Named colors use index numbers starting at 0 and decreasing to -19, since there are 20 named colors.
- a dynamically loaded colormap that can be changed at will.
  Dynamically loaded colors use color indexes starting at 1 and increasing to the number of colors in the colormap. See `COLORMAP` and `COLORMAPFILE`.

The named colors are shown below.

Expressions