Listening to The Projection Booth's super-sized episode on Star Wars, and during their interview with ANH Set Decorator Roger Christian, he says "[There were] a lot of discussions over how dark the [Death Star] walls should be. John [Barry, set designer] wanted them really black, but the lighting camera couldn't cope with it being so dark, so they got stage by stage, they got lighter and lighter so it reached a compromise, in effect."

Just pointing out that the set designer wanted the Death Star to be black and white.