colour.colorimetry.whiteness_Ganz1979¶
-
colour.colorimetry.
whiteness_Ganz1979
(xy, Y)[source]¶ Returns the whiteness index \(W\) and tint \(T\) of given sample CIE xy chromaticity coordinates using Ganz and Griesser (1979) method.
- Parameters
xy (array_like) – Chromaticity coordinates CIE xy of sample.
Y (numeric or array_like) – Tristimulus \(Y\) value of sample.
- Returns
Whiteness \(W\) and tint \(T\).
- Return type
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
Examples
>>> import numpy as np >>> xy = np.array([0.3167, 0.3334]) >>> whiteness_Ganz1979(xy, 100) array([ 85.6003766..., 0.6789003...])