Temperature in kelvin of a full spectrum radiator closest to the color appearance of a light source at the same brightness.
Unit: kelvin, K
Contrast C (between two parts of a visual field)
The relevant luminance difference between two parts
in accordance with the formula:
C=L1 – L2
Where the size of the two parts differs greatly and where:
L1 = luminance of the smallest part (object)
L2 = luminance of the largest part (background).