Is there a tool to deal with a very dark corner of an old photo?

[AntiqueFlaneur]

I'm attaching a screenshot of a scanned photo I'm trying to remaster. I've straightened it out, done FFT denoise, and am trying to use a curves adjustment layer to improve the image quality. The problem I'm having is that one side of the image is extremely dark. Most of the photo needs to be darkened a bit via curves, but when I do this the left corner turns very dark. Any way to deal with this? I'm also attaching my .afphoto file of the image as well. 

 

Thanks!

DarkSide.afphoto

[Jowday]

7 minutes ago, AntiqueFlaneur said:

I'm attaching a screenshot of a scanned photo I'm trying to remaster. I've straightened it out, done FFT denoise, and am trying to use a curves adjustment layer to improve the image quality. The problem I'm having is that one side of the image is extremely dark. Most of the photo needs to be darkened a bit via curves, but when I do this the left corner turns very dark. Any way to deal with this? I'm also attaching my .afphoto file of the image as well. 

Thanks!

DarkSide.afphoto 26.8 MB · 0 downloads

Gradient masks, perhaps there is help in this one:

 

[smadell]

A nice technique for removing shadows, demonstrated by PixImperfect. It is a Photoshop tutorial, but should translate fairly easily to Affinity Photo. Do this prior to adjusting the photo (as a whole) with Curves and other stuff.

Here's a VERY rough attempt at it:

[v_kyr]

Maybe into this direction also with a little bit of tonal adjustments etc.