colour.colorimetry.yellowness_ASTMD1925#

colour.colorimetry.yellowness_ASTMD1925(XYZ: ArrayLike) NDArrayFloat[source]#

Return the yellowness index \(YI\) of given sample CIE XYZ tristimulus values using ASTM D1925 method.

ASTM D1925 has been specifically developed for the definition of the yellowness of homogeneous, non-fluorescent, almost neutral-transparent, white-scattering or opaque plastics as they will be reviewed under daylight condition. It can be other materials as well, as long as they fit into this description.

Parameters:

XYZ (ArrayLike) – CIE XYZ tristimulus values of the sample.

Returns:

Yellowness \(YI\).

Return type:

np.float or numpy.ndarray

Notes

Domain

Scale - Reference

Scale - 1

XYZ

[0, 100]

[0, 1]

Range

Scale - Reference

Scale - 1

YI

[0, 100]

[0, 1]

  • Input CIE XYZ tristimulus values must be adapted to CIE Illuminant C.

References

[ASTMInternational15b], [XRitePantone12]

Examples

>>> XYZ = np.array([95.00000000, 100.00000000, 105.00000000])
>>> yellowness_ASTMD1925(XYZ)  
10.2999999...