colour.colorimetry.yellowness Module¶
Yellowness Index \(Y\)¶
Defines yellowness index \(Y\) computation objects:
See also
References
[1] | (1, 2) X-Rite, & Pantone. (2012). Color iQC and Color iMatch Color Calculations Guide. Retrieved from http://www.xrite.com/documents/literature/en/09_Color_Calculations_en.pdf |
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colour.colorimetry.yellowness.
yellowness_ASTMD1925
(XYZ)[source]¶ Returns the yellowness index \(YI\) of given sample CIE XYZ tristimulus values using ASTM D1925 method. [1]
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 (array_like) – CIE XYZ tristimulus values of sample. Returns: Whiteness \(YI\). Return type: numeric or ndarray Notes
- Input CIE XYZ tristimulus values are in domain [0, 100].
Warning
The input domain of that definition is non standard!
Examples
>>> import numpy as np >>> XYZ = np.array([95.00000000, 100.00000000, 105.00000000]) >>> yellowness_ASTMD1925(XYZ) 10.2999999...
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colour.colorimetry.yellowness.
yellowness_ASTME313
(XYZ)[source]¶ Returns the yellowness index \(YI\) of given sample CIE XYZ tristimulus values using ASTM E313 method. [1]
ASTM E313 has successfully been used for a variety of white or near white materials. This includes coatings, Plastics, Textiles.
Parameters: XYZ (array_like) – CIE XYZ tristimulus values of sample. Returns: Whiteness \(YI\). Return type: numeric or ndarray Notes
- Input CIE XYZ tristimulus values are in domain [0, 100].
Warning
The input domain of that definition is non standard!
Examples
>>> import numpy as np >>> XYZ = np.array([95.00000000, 100.00000000, 105.00000000]) >>> yellowness_ASTME313(XYZ) 11.0650000...
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colour.colorimetry.yellowness.
YELLOWNESS_METHODS
= CaseInsensitiveMapping({u'ASTM E313': <function yellowness_ASTME313>, u'ASTM D1925': <function yellowness_ASTMD1925>})¶ Supported yellowness computations methods.
- YELLOWNESS_METHODS : CaseInsensitiveMapping
- {‘ASTM E313’, ‘ASTM D1925’}
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colour.colorimetry.yellowness.
yellowness
(XYZ, method=u'ASTM E313')[source]¶ Returns the yellowness \(W\) using given method.
Parameters: - XYZ (array_like) – CIE XYZ tristimulus values of sample.
- method (unicode, optional) – {‘ASTM E313’, ‘ASTM D1925’}, Computation method.
Returns: yellowness \(Y\).
Return type: numeric or ndarray
Examples
>>> import numpy as np >>> XYZ = np.array([95.00000000, 100.00000000, 105.00000000]) >>> yellowness(XYZ) 11.0650000... >>> method = 'ASTM D1925' >>> yellowness(XYZ, method=method) 10.2999999...