I seriously hope this hasn't been debated already, as I did a search for this and didn't yield any results.
Anyway, there is some debate going on at (evil) RS about the color of Jedi Luke's cloak, and what color it should be when made.
Personally, I always thought the robe was brown like the vintage figure. It certainly CAN look black at points in the movie, but that is due to some serious backlight as Luke is entering Jabba's Palace.
Anyway, what is your take: black or brown?