Setting temperature to default value in color calibration module leads to cast

[priort (Todd Prior)]

The K values in color calibration don’t really mean anything…so if you set it to 5000 K or some other desired WB you might introduce an unexpected cast. I am not the one to explain this properly but this is not a traditional WB linked to K values. I will see if I can find you the reference…If the initial default calcultated by CC is not what you want use the picker on a neutral element or change the selection to custom for the illuminant and you will get a hue chroma slider pair. Usually just tweaking the chroma of the calculated hue will dial in your WB.

https://darktable-org.github.io/dtdocs/module-reference/processing-modules/color-calibration/

EDIT…
Quick explanation in this comment. Also a ton of information in the entire thread

Issue with white balance and color calibration on Darktable 3.5 (master)

Well discussed here in and around Nov and Dec time frame WB Module to D65-then input profile-then color calibration to D50… Quoted from AP posting in the thread linked above “Don’t even try to compare temperature readings from both modules. Again, color calibration takes an input that is already pre-corrected by white balance and input profile.”