colour.colorimetry.illuminants Module


Defines CIE illuminants computation related objects:

See also

Illuminants Jupyter Notebook colour.colorimetry.dataset.illuminants.d_illuminants_s_spds, colour.colorimetry.spectrum.SpectralPowerDistribution


Returns the relative spectral power distribution of given CIE Standard Illuminant D Series using given xy chromaticity coordinates.


[1]Wyszecki, G., & Stiles, W. S. (2000). CIE Method of Calculating D-Illuminants. In Color Science: Concepts and Methods, Quantitative Data and Formulae (pp. 145–146). Wiley. ISBN:978-0471399186
[2]Lindbloom, B. (2007). Spectral Power Distribution of a CIE D-Illuminant. Retrieved April 05, 2014, from
Parameters:xy (array_like) – xy chromaticity coordinates.
Returns:CIE Standard Illuminant D Series relative spectral power distribution.
Return type:SpectralPowerDistribution


>>> xy = np.array([0.34570, 0.35850])
>>> print(D_illuminant_relative_spd(xy))
SpectralPowerDistribution('CIE Standard Illuminant D Series', (300.0, 830.0, 10.0))

CIE Standard Illuminant A is intended to represent typical, domestic, tungsten-filament lighting. Its relative spectral power distribution is that of a Planckian radiator at a temperature of approximately 2856 K. CIE Standard Illuminant A should be used in all applications of colorimetry involving the use of incandescent lighting, unless there are specific reasons for using a different illuminant.

Parameters:wl (array_like) – Wavelength to evaluate the function at.
Returns:CIE Standard Illuminant A value at given wavelength.
Return type:ndarray


[1]CIE TC 1-48. (2004). 3.1 Recommendations concerning standard physical data of illuminants. In CIE 015:2004 Colorimetry, 3rd Edition (pp. 12–13). ISBN:978-3-901-90633-6


>>> wl = np.array([560, 580, 581.5])
>>> CIE_standard_illuminant_A_function(wl)  
array([ 100.        ,  114.4363383...,  115.5285063...])