I saw a photography on google images when I was bored enough to try to fix discolored photographs, but I found that one photograph with a extreme case of blue-green tint all over the photograph, and I find it extremely difficult to fix. A couple of people have managed to fix it to a degree with the use of RawTherapee or Photoshop. How would you even fix that case? Red tinted photographs are way easier to fix.
Re copper-bronze-dichroic-film-photo.jpg : if you look at the pixel values of the central section, you’ll see that almost all pixels have zero in the red channel. The data has gone, and no tweaking will recover it.
Of course, we can still guess values for the red channel. Say, the average of the red and green channels, but a bit less at the top (for the blue sky) and a bit more for the bottom (the red road surface).
The tourist photo hasn’t lost as much data. Tweaking reveals the young man’s top is green, and the car is red. But that much tweaking of a JPG creates banding.
I was able to get to here with the tourist photo (2 Versions) -
First, this was RGB Adjustment, and then swap into LAB adjustment, and then applied another layer of RGB adjustment. One was more intended to have white color, and the other is more intended to have colors preserved.
Not sure how I can fix up the trees on the background. I believe RGB Tone in G’MIC can fix it up.
That being said, there must some way to recover lost information or at least have some convincing way to look like as if they have been recovered.
