colour.lightness

colour.lightness(Y, method=u'CIE 1976', **kwargs)[source]

Returns the Lightness \(L\) using given method.

Parameters:
  • Y (numeric or array_like) – luminance \(Y\).
  • method (unicode, optional) – {‘CIE 1976’, ‘Glasser 1958’, ‘Wyszecki 1963’, ‘Fairchild 2010’, ‘Fairchild 2011’}, Computation method.
Other Parameters:
 
Returns:

Lightness \(L\).

Return type:

numeric or array_like

Notes

  • Input luminance \(Y\) and optional \(Y_n\) are in domain [0, 100] or [0, \(\infty\)].
  • Output Lightness \(L\) is in range [0, 100].

References

Examples

>>> lightness(10.08)  
37.9856290...
>>> lightness(10.08, Y_n=100)  
37.9856290...
>>> lightness(10.08, Y_n=95)  
38.9165987...
>>> lightness(10.08, method='Glasser 1958')  
36.2505626...
>>> lightness(10.08, method='Wyszecki 1963')  
37.0041149...
>>> lightness(10.08 / 100, epsilon=1.836, method='Fairchild 2010')
... 
24.9022902...