colour.colorimetric_purity

colour.colorimetric_purity(xy, xy_n, cmfs=XYZ_ColourMatchingFunctions(name='CIE 1931 2 Degree Standard Observer', ...))[source]

Returns the colorimetric purity \(P_c\) for given colour stimulus \(xy\).

Parameters:
  • xy (array_like) – Colour stimulus CIE xy chromaticity coordinates.
  • xy_n (array_like) – Achromatic stimulus CIE xy chromaticity coordinates.
  • cmfs (XYZ_ColourMatchingFunctions, optional) – Standard observer colour matching functions.
Returns:

Colorimetric purity \(P_c\).

Return type:

numeric or array_like

References

[CIETC1-482004o], [Erdogana]

Examples

>>> xy = np.array([0.54369557, 0.32107944])
>>> xy_n = np.array([0.31270000, 0.32900000])
>>> cmfs = CMFS['CIE 1931 2 Degree Standard Observer']
>>> colorimetric_purity(xy, xy_n, cmfs)  # doctest: +ELLIPSIS
0.6135828...