I agree with you on this, Zombie. This is definitely one of the best references we got, it's just that almost all those photos sports a subtle green tint, not just the Death Star, it's even on the Blockade Runner interior shots. But as I've already said, I agree that the walls on the Death Star shouldn't be neutral gray, I actually don't know where this thought comes from, to me they have always looked like they had different shades of blu/green in them, are the walls not like that, even in the gout? I can see that the actual picture you posted is washed out gray, but is it really like that throughout the film?