Colour Temperature & Correlated Colour Temperature¶

The colour temperature noted $T_c$ is the temperature of a Planckian radiator whose radiation has the same chromaticity as that of a given stimulus. [1]

The correlated colour temperature noted $T_{cp}$ and shortened to $CCT$ is the temperature of the Planckian radiator having the chromaticity nearest the chromaticity associated with the given spectral distribution on a diagram where the (CIE 1931 2° Standard Observer based) $u^\prime, \cfrac{2}{3}v^\prime$ coordinates of the Planckian locus and the test stimulus are depicted. [2]

The CIE Standard Illuminant A, CIE Standard Illuminant D65 and CIE Illuminant E illuminants plotted in the CIE 1960 UCS Chromaticity Diagram:

In [1]:

import colour

from colour.plotting import *

In [2]:

colour_style();

In [3]:

with colour.utilities.suppress_warnings(python_warnings=True):
    plot_planckian_locus_in_chromaticity_diagram_CIE1960UCS(['A', 'D65', 'E']);

In [4]:

# Zooming into the *Planckian Locus*.
with colour.utilities.suppress_warnings(python_warnings=True):
    plot_planckian_locus_in_chromaticity_diagram_CIE1960UCS(
        ['A', 'D65', 'E'], bounding_box=[0.15, 0.35, 0.25, 0.45]);