Different display = bad gamma settings applied

[Harmonica]

Accidentally running the game on a different display to normal somehow overrides the game's default settings for gamma.. now everything is kind of washed out and grey, where before it had darker blacks and good contrast. At the same time it also somehow increased the saturation of the colours (most obvious on the main screen, the operators have way more colour on them than previously).

Has anyone had this problem and fixed it? I can't really find anything about it. Maybe there's a file somewhere I can delete to get the game back to default gamma settings.

edit: okay, toggling the game to windowed and back to fullscreen seems to have reset the gamma so I have better black levels, but the colours are still over saturated. Also it messed up my second displays colour profile until I restarted...