Cubehelix Palettes

Cubehelix was designed by D.A. Green to provide a color mapping that would degrade gracefully to grayscale without losing information. This quality makes Cubehelix useful for continuous color scales in scientific visualizations that might be printed in grayscale at some point.

The palettable.cubehelix module provides several pre-made Cubehelix palettes, or you can make your own.

See Also

• A colour scheme for the display of astronomical intensity images, D.A. Green (2011) Bulletin of the Astronomical Society of India, 39, 289
• Cubehelix, or How I Learned to Love Black & White Printers by James Davenport.

Contents

• Previews

  • classic_16
  • cubehelix1_16
  • cubehelix2_16
  • cubehelix3_16
  • jim_special_16
  • perceptual_rainbow_16
  • purple_16
  • red_16

• Making your own Cubehelix palette

Previews

classic_16

cubehelix1_16

cubehelix2_16

cubehelix3_16

jim_special_16

perceptual_rainbow_16

purple_16

red_16

Making your own Cubehelix palette

With the Cubehelix.make classmethod you can create arbitrary Cubehelix palettes. For example:

from palettable.cubehelix import Cubehelix
palette = Cubehelix.make(start=0.3, rotation=-0.5, n=16)

and then use that palette instance as usual.

Cubehelix.make Argument Reference

• start (scalar, optional). Sets the starting position in the RGB color space. 0=blue, 1=red, 2=green. Default is 0.5 (purple).
• rotation (scalar, optional). The number of rotations through the rainbow. Can be positive or negative, indicating direction of rainbow. Negative values correspond to Blue→Red direction. Default is -1.5.
• start_hue (scalar, optional). Sets the starting color, ranging from (-360, 360). Combined with end_hue, this parameter overrides start and rotation. This parameter is based on the D3 implementation by @mbostock. Default is None.
• end_hue (scalar, optional) Sets the ending color, ranging from (-360, 360). Combined with start_hue, this parameter overrides start and rotation. This parameter is based on the D3 implementation by @mbostock. Default is None.
• gamma (scalar, optional). The gamma correction for intensity. Values of gamma < 1 emphasize low intensities while gamma > 1 emphasises high intensities. Default is 1.0.
• sat (scalar, optional). The uniform saturation intensity factor. sat=0 produces grayscale, while sat=1 retains the full saturation. Setting sat>1 oversaturates the color map, at the risk of clipping the color scale. Note that sat overrides both min_stat and max_sat if set.
• min_sat (scalar, optional). Saturation at the minimum level. Default is 1.2.
• max_sat (scalar, optional). Satuation at the maximum level. Default is 1.2.
• min_light (scalar, optional). Minimum lightness value. Default is 0.
• max_light (scalar, optional). Maximum lightness value. Default is 1.
• n (scalar, optional). Number of discrete rendered colors. Default is 256.
• reverse (bool, optional). Set to True to reverse the color map. Will go from black to white. Good for density plots where shade → density. Default is False.
• name (str, optional). Name of the color map (defaults to 'custom_cubehelix').