One other thing I wanted to mention is that I found ROTJ to be extremely noisy - more so than the other two (I notice these quality problems much more now that I’m looking at in on a large 4K screen) and also the crushed black are just completely unrecoverable in some scenes. But the noisiness is interesting, because the movie bears clear signs of having tons of automatic grain removal applied, which would never leave so much noise in it, so I figure some of it must be added on top and then I was comparing the BD to a few ProResHQ 422 clips from the original master from which the BD was made (don’t ask me where I got those and I’ll tell you no lies - but they are just three very short clips) and I noticed something interesting:
http://s25.postimg.org/olq4fyubx/Pro_Res.jpg
The noise (exaggerated in that screenshot for better visibility) that is in the image overlaps into the black bars, which is only possible, if it was added on top of the picture.