A few b&w contact sheets of the first film I don't think I've seen before: http://theeditroomfloor.blogspot.se/2013/06/unseen-photos-from-star-wars-death-star.html#!/2013/06/unseen-photos-from-star-wars-death-star.html It's sad they are in such poor quality.
Lord Dark Helmet without his cape in a rehearsal. See the battery pack hanging from his waist.