If you go to a good tattoo parlour there should be no worry about it turning green as only inferiour ink turns green.
See, now I'm bummed...Mine have definetly turned green/blue..But, they're really old....I guess it's common for old tatts, done before they got real popular again...? Hmmm.. Maybe my greenish blue tattoo's can be cool, & considered oldskool?
my black never turned green, so what was the reason this tattoo artist told you it turns green, I'm curious.