colour.colorimetry.intermediate_lightness_function_CIE1976#

colour.colorimetry.intermediate_lightness_function_CIE1976(Y: ArrayLike, Y_n: ArrayLike = 100) → NDArrayFloat[source]#

Return the intermediate value \(f(Y/Yn)\) in the Lightness \(L^*\) computation for given luminance \(Y\) using given reference white luminance \(Y_n\) as per CIE 1976 recommendation.

Parameters:

Y (ArrayLike) – Luminance \(Y\).
Y_n (ArrayLike) – White reference luminance \(Y_n\).

Returns:

Intermediate value \(f(Y/Yn)\).

Return type:

numpy.ndarray

Notes

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

Range	Scale - Reference	Scale - 1
`f_Y_Y_n`	[0, 1]	[0, 1]

References

[CIET14804h], [WS00l]

Examples

>>> intermediate_lightness_function_CIE1976(12.19722535)
... 
0.4959299...
>>> intermediate_lightness_function_CIE1976(12.19722535, 95)
... 
0.5044821...