Within the Jedi Order, it seemed to be that the brown robe over the lighter coloured tunic, pants and belt was more uniform than merely a customary wardrobe for Jedi Knights and Jedi Masters. I can't recall any other Jedi who wore any kind of variation from this outfit (I can only think of the Jocasta Nu who was the librarian in Episode II in the Jedi Archives, but she was at that time a Jedi Knight of some standing).
And then there was Anakin in Episode III, in his black robe and tunic, looking very different from any other Jedi. I realise that he was a big war hero, but he wasn't even a Jedi Master so it seems unlikely that his choice of attire would be welcomed by the Jedi Council.
So my question is this: Why was Anakin Skywalker, as a mere Jedi Knight, allowed to wear his black robes instead of the typical Jedi brown?