colour.RGB_luminance_equation

colour.RGB_luminance_equation(primaries, whitepoint)[source]

Returns the luminance equation from given primaries and whitepoint.

Parameters:
  • primaries (array_like, (3, 2)) – Primaries chromaticity coordinates.
  • whitepoint (array_like) – Illuminant / whitepoint chromaticity coordinates.
Returns:

Luminance equation.

Return type:

unicode

Examples

>>> p = np.array([0.73470, 0.26530, 0.00000, 1.00000, 0.00010, -0.07700])
>>> whitepoint = np.array([0.32168, 0.33767])
>>> # Doctests skip for Python 2.x compatibility.
>>> RGB_luminance_equation(p, whitepoint)  # doctest: +SKIP
'Y = 0.3439664...(R) + 0.7281660...(G) + -0.0721325...(B)'