Ifixit has this page on how to calibrate the screen in the Libra Colour, Clara Colour and Clara BW.
https://www.ifixit.com/Guide/How+to+...Display/170983
Some people have already changed their vcom values to another from a device in which they liked the screen colour more, and it worked.
Seems like lower values make the screen more cooler while higher ones turn it more warm.
My Libra Colour vcom value is -1470, and tried to change it to -1313 and -1294 (Values from other Libra Colours) but it didn't change anything. I'm also not comfortable in opening it up to see the correct vcom value on the display cable.
If anyone tries it, please tell us if it worked and how it changed.
It could also be nice to see what different vcom values there exists and maybe have a list people could try on their devices without having to open it.