Ask HN: Selectively changing the color of characters in an animated video?

I have seen some references to libraries that can colorize black and white video and even a few related projects like changing the new Lion King movie to be more like the original animated video.

But what I am interested in, is a way to selectively change colors of characters in animated films. Specifically, I want to change the skin tone of some animated characters.

A few months ago I think I saw a project here on HN that was adjusting skin tone in photos and maybe videos, though I can't find it.

Is anyone aware of any projects or libraries that are already doing this?