User blog comment:The Bonehead Skipper/Color of Armament/@comment-3119203-20101124232702/@comment-3060121-20101125031716

I'm going with the guy above you. I think that the color only changes when the user enhances its size. Luffy's arm didn't change when he used haki and gear second together. And we know that he used haki against the pacifista because Sentamaru comments on it.