gamma correction

Automatic gamma correction via set palette gamma <gamma> can be done for gray maps (set palette gray) and for the cubehelix color palette schemes. Gamma = 1 produces a linear ramp of intensity. See test palette.

For gray mappings, <gamma> defaults to 1.5 which is usually suitable.

The gamma correction is applied to the cubehelix color palette family, but not to other palette coloring schemes. However, you may easily implement gamma correction for explicit color functions.

Example:

      set palette model RGB
      set palette functions gray**0.64, gray**0.67, gray**0.70

To use gamma correction with interpolated gradients specify intermediate gray values with appropriate colors. Instead of

      set palette defined ( 0 0 0 0, 1 1 1 1 )

use e.g.

      set palette defined ( 0 0 0 0, 0.5 .73 .73 .73, 1 1 1 1 )

or even more intermediate points until the linear interpolation fits the "gamma corrected" interpolation well enough.