colour.models.hunter_rdab Module

Hunter Rd,a,b Colour Scale

Defines the Hunter Rd,a,b colour scale transformations:

See also

Hunter Rd,a,b Colour Scale Jupyter Notebook

References

[1]HunterLab. (2012). Hunter Rd,a,b Color Scale – History and Application. Retrieved from https://hunterlabdotcom.files.wordpress.com/2012/07/an-1016-hunter-rd-a-b-color-scale-update-12-07-03.pdf
colour.models.hunter_rdab.XYZ_to_Hunter_Rdab(XYZ, XYZ_n=array([ 96.38, 100., 82.45]), K_ab=array([ 173.51, 58.48]))[source]

Converts from CIE XYZ tristimulus values to Hunter Rd,a,b colour scale.

Parameters:
  • XYZ (array_like) – CIE XYZ tristimulus values.
  • XYZ_n (array_like, optional) – Reference illuminant tristimulus values.
  • K_ab (array_like, optional) – Reference illuminant chromaticity coefficients, if K_ab is set to None it will be computed using XYZ_to_K_ab_HunterLab1966().
Returns:

Hunter Rd,a,b colour scale array.
Return type:

ndarray

Notes

  • Input CIE XYZ and reference illuminant tristimulus values are in domain [0, 100].

Examples

>>> import numpy as np
>>> XYZ = np.array([0.07049534, 0.10080000, 0.09558313]) * 100
>>> D50 = HUNTERLAB_ILLUMINANTS[
...     'CIE 1931 2 Degree Standard Observer']['D50']
>>> XYZ_to_Hunter_Rdab(
...     XYZ,
...     D50.XYZ_n,
...     D50.K_ab)   
array([ 10.08      , -18.6765376...,  -3.4432992...])