…it’d be best if you can create a 19201660 resolution file instead of 12551080…
…downrez the corrected file to 1920*1660 (approx) and share it with us.
This, please! 😄
Also, how would you go about brightening the dark parts? Gamma correction? Because I would advise against just raising the brightness, because that would simply wash-out the image (blacks become grey, etc.).
I think the scenes would be best served by staying as dark as they are on the scan, but with as much crushed detail retrieved as possible without making the image literally brighter (I have zero knowledge about how possible this scenario is under the digital circumstances).