colour.yellowness

colour.yellowness(XYZ: Domain100, method: Literal['ASTM D1925', 'ASTM E313', 'ASTM E313 Alternative'] | str = 'ASTM E313', **kwargs: Any) → Range100

Compute the yellowness index \(YI\) using the specified method.

Parameters:

• XYZ (Domain100) – CIE XYZ tristimulus values of the sample.

• method (Literal['ASTM D1925', 'ASTM E313', 'ASTM E313 Alternative'] | str) – Computation method.

• C_XZ – {colour.colorimetry.yellowness_ASTME313()}, Coefficients \(C_X\) and \(C_Z\) for the CIE 1931 2 Degree Standard Observer and CIE 1964 10 Degree Standard Observer with CIE Illuminant C and CIE Standard Illuminant D65.

• kwargs (Any)

Returns:

Yellowness index \(YI\).

Return type:

numpy.ndarray

Notes

Domain	Scale - Reference	Scale - 1
XYZ	100	1

Range	Scale - Reference	Scale - 1
YI	100	1

References

[ASTMInternational15b], [XRitePantone12]

Examples

>>> XYZ = np.array([95.00000000, 100.00000000, 105.00000000])
>>> yellowness(XYZ)
4.3400000...
>>> yellowness(XYZ, method="ASTM E313 Alternative")
11.0650000...
>>> yellowness(XYZ, method="ASTM D1925")
10.2999999...