# colour.colorimetry.yellowness_ASTME313_alternative#

colour.colorimetry.yellowness_ASTME313_alternative(XYZ: ArrayLike) NDArrayFloat[source]#

Return the yellowness index $$YI$$ of given sample CIE XYZ tristimulus values using the alternative ASTM E313 method.

In the original form of Test Method E313, an alternative equation was recommended for a yellowness index. In terms of colorimeter readings, it was $$YI = 100(1 − B/G)$$ where $$B$$ and $$G$$ are, respectively, blue and green colorimeter readings. Its derivation assumed that, because of the limitation of the concept to yellow (or blue) colors, it was not necessary to take account of variations in the amber or red colorimeter reading $$A$$. This equation is no longer recommended.

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

Examples

>>> XYZ = np.array([95.00000000, 100.00000000, 105.00000000])
>>> yellowness_ASTME313_alternative(XYZ)
11.0650000...