If you want a quick-and-dirty inversion, you can take a tone curve tool, set it to the XYZ color space and make it go top-left to bottom-right instead of the no

If you want a quick-and-dirty inversion, you can take a tone curve tool, set it to the XYZ color space and make it go top-left to bottom-right instead of the normal bottom-left to top-right. That should work afaik.