Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 128)

Caution
When setting the color temperature for an artificial light source, set the white
balance correction (magenta or green bias) as necessary.
When setting <
> to a value measured with a commercially available color
temperature meter, take some test shots in advance and adjust the setting as
needed to compensate for any difference between the color temperature meter and
the camera.
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