colour.yellowness¶

colour.yellowness(XYZ, method='ASTM E313', **kwargs)[source]¶

Returns the yellowness \(W\) using given method.

Parameters

XYZ (array_like) – CIE XYZ tristimulus values of sample.
method (str, optional) – {‘ASTM E313’, ‘ASTM D1925’, ‘ASTM E313 Alternative’}, Computation method.
C_XZ (array_like, optional) – {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 and CIE Illuminant C and CIE Standard Illuminant D65.

Returns

yellowness \(Y\).

Return type

numeric or ndarray

Notes

Domain	Scale - Reference	Scale - 1
`XYZ`	[0, 100]	[0, 1]

Range	Scale - Reference	Scale - 1
`YI`	[0, 100]	[0, 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...