Anakin Skywalker’s look in Episodes 2 and 3 was meticulously designed by George Lucas.
In Art of Revenge of the Sith, we see concept art drawn by Ian McCaig where he says, “George wanted Anakin to look more like Qui-Gon Jinn, to show that he was going beyond what Obi-Wan was teaching him - hence the long hair.”
Hayden Christensen’s flowing locks were not there to make him look attractive, Lucas was telling us Anakin’s power had already extended beyond what the Jedi were capable of.
Even his robes have a significant meaning. While there was no dress code or uniform for Jedi, in Attack of the Clones we see, as a padawan, Anakin had already refused to conform to the Jedi standard of tan and brown.
We understand why Lucas and his team wanted these darker colors - I mean this is Darth Vader - but Anakin was already rebelling, and the material selection was telling. His surcoat, made of synthetic leather, provided more protection than cloth garments. The concept of always being prepared and protected was so important to him it came through in his clothing choices.
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