Here's some stuff I did to restore color to the Chinese spacewalk photo and then to show that underwater CAN be made to look like real life.
I believe China played around with the green curves a bit, but when I restored the blue fairly close to the ISS, you can see how the foreground originally looked. A LOT like it was shot underwater, if I do say so, myself.
Then here I took a Johnson Space Center photo of some STS astronauts training for a spacewalk and showed how it is possible to reduce the blue from the image to make it appear like it was NOT shot underwater.
Here is what I did:
First, I reduced some of the blue from the image. That left me pretty "greened", so I went ahead and reduced that and then went down and down until I found a fairly close color image. Next, I added some red to the image. Red is the first color in the spectrum to disappear underwater and so some of it must be restored to get a good view of how this photo would have looked if not taken underwater.