# colour.colorimetry.whiteness_Ganz1979¶

colour.colorimetry.whiteness_Ganz1979(xy, Y)[source]

Returns the whiteness index $$W$$ and tint $$T$$ of given sample xy chromaticity coordinates using Ganz and Griesser (1979) method.

Parameters: xy (array_like) – Chromaticity coordinates xy of sample. Y (numeric or array_like) – Tristimulus $$Y$$ value of sample. Whiteness $$W$$ and tint $$T$$. ndarray

Notes

Domain Scale - Reference Scale - 1
Y [0, 100] [0, 1]
Range Scale - Reference Scale - 1
WT [0, 100] [0, 1]
• The formula coefficients are valid for CIE Standard Illuminant D Series D65 and CIE 1964 10 Degree Standard Observer.
• Positive output tint $$T$$ values indicate a greener tint while negative values indicate a redder tint.
• Whiteness differences of less than 5 Ganz units appear to be indistinguishable to the human eye.
• Tint differences of less than 0.5 Ganz units appear to be indistinguishable to the human eye.

References

[XRP12]

Examples

>>> import numpy as np
>>> xy = np.array([0.3167, 0.3334])
>>> whiteness_Ganz1979(xy, 100)  # doctest: +ELLIPSIS
array([ 85.6003766...,   0.6789003...])