Since it was mentioned a few pages back, I do all my edits with gimp and skin tone can be tricky but it depends on the character.
If it's just a usual white gal like Babs or Stargirl, no worries - Maybe use a layer of soft light
If it's Raven or Starfire, it's a bit trickier but I usually try to go with Babs skin tone as base and do layers over top with Lch Color (lighter tone) or hsl Color (which goes a bit darker but more flat).
It's just eyeballing from there with soft light layer or multi layer if you don't feel it matches up, in the end I find it's just a personal call as to know when to say you're finished (aside from noticing tiny flaws after you say mission accomplished
).
I also just go with the game stripe rips rather than dealing with the HD rips since it's all just mashing up assets anyway, let alone you could just upscale with waifux2 if you need to.
Lately, I've just been sticking with VAM but that Gotham update had some stellar stuff and of course, you guys do great work on here as always. Truly humbled by some of the stuff pulled off on here.