In A New Hope, Luke’s all-white clothes make a stark contrast with Vader’s all-black ensemble hearkening back to the serial westerns of the 1940s and 1950s, in which the goods wore white and the bads, black. Luke’s outfits continue to emphasize his characterization in this way throughout the trilogy. In The Empire Strikes Back, when he journeys to meet Yoda or to rescue his friends on Bespin, his fatigues are a light gray, showing that he has traveled from the innocent idealism of his youth and has placed himself in peril of straying to the Dark Side. By the time we get to Return of the Jedi, he has adopted an all-black wardrobe, not meaning he has gone over to the Dark Side, but instead, recalling a priest or monk’s garb, and linking him visually to his father, with whose fate he is so deeply connected with.
the symbolism of color in Luke’s wardrobe is capped at the very end of RotJ, where the lapels of his jacket open up to show they had a white lining, showing that even though he came close to falling into darkness, good was always at his core.