Fixing photos with bad lighting
I tried this in GIMP and it seems to work okay:
Open up the photo and duplicate the layer containing it.
Invert the duplicated layer. (The shortcut is Control/Command+I in Photoshop and is likely the same in other image editors.)
Set the duplicated layer’s blending mode to Overlay.
Optional: Reduce the opacity of the duplicated layer if the effects are too much.
Optional: Merge the two layers and adjust the levels or curves to suit your taste. (If you’re in Photoshop, you can just make a new adjustment layer to do this.)
An alternative method I found in the comments:
1. duplicate the layer
2. desaturated it
3. invert the colors
4. add a gaussian blur, say about 10 pixels
5. make the layer overlay
optional mentioned in the article also applies.
It looks like just increasing the gamma would do the trick
That is clever, I’ll be using that in the future…