colour.colorimetry.whiteness_Ganz1979

colour.colorimetry.whiteness_Ganz1979(xy: ArrayLike, Y: Annotated[_Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str], 100]) → Annotated[ndarray[tuple[Any, ...], dtype[float16 | float32 | float64]], 100]

Compute the whiteness index \(W\) and tint \(T\) of the specified sample CIE xy chromaticity coordinates using the Ganz and Griesser (1979) method.

Parameters:

• xy (ArrayLike) – Chromaticity coordinates CIE xy of the sample.

• Y (Annotated[_Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | complex | bytes | str | _NestedSequence[complex | bytes | str], 100]) – Tristimulus \(Y\) value of the sample.

Returns:

Whiteness \(W\) and tint \(T\).

Return type:

numpy.ndarray

Notes

Domain	Scale - Reference	Scale - 1
Y	100	1

Range	Scale - Reference	Scale - 1
WT	100	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

[XRitePantone12]

Examples

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