#### 1.17.1 colorspec

Many commands allow you to specify a linetype with an explicit color. Terminal-independent color choice is only possible for terminals that support RGB color or pm3d palettes.

Syntax:

          ... {linecolor | lc} {<colorspec> | <n>}
          ... {textcolor | tc} {<colorspec> | {linetype | lt} <n>}

where <colorspec> has one of the following forms:

          rgbcolor "colorname"
          rgbcolor "#RRGGBB"
          rgbcolor variable       # color is read from input file
          palette frac <val>      # <val> runs from 0 to 1
          palette cb <value>      # <val> lies within cbrange
          palette z
          variable                # color index is read from input file

The "<n>" is the linetype number the color of which is used, see test.

"colorname" refers to one of the color names built in to gnuplot. For a list of the available names, see colornames.

"#RRGGBB" is a hexadecimal constant preceded by the "#" symbol. The RRGGBB represents the red, green, and blue components of the color, each on a scale from 0 - 255. For example, magenta = full-scale red + full-scale blue would be represented by #FF00FF, which is the hexadecimal representation of (255 << 16) + (0 << 8) + (255).

The color palette is a linear gradient of colors that smoothly maps a single numerical value onto a particular color. Two such mappings are always in effect. ‘palette frac‘ maps a fractional value between 0 and 1 onto the full range of the color palette. ‘palette cb‘ maps the range of the color axis onto the same palette. See cbrange. See also ‘set colorbox‘. You can use either of these to select a constant color from the current palette.

"palette z" maps the z value of each plot segment or plot element into the cbrange mapping of the palette. This allows smoothly-varying color along a 3d line or surface. It also allows coloring 2D plots by palette values read from an extra column of data (not all 2D plot styles allow an extra column).