To me the Seneca native's skin on the hand seems a bit to reddish. I find these photos to have very high saturation. I think this could be adjusted and get subtler effects. It's still amazing that this is possible with no human intervention but at the same time, from a different perspective, I find that the originals have their own charm that I would leave it like that.
Is it unthinkable that the seneca girl actually had her hand painted red, for decoration or as a symbol of something? Perhaps her father/brother etc was a fighter and this was a way to keep spirits up while he was in the war?