The Jabba subtitles and the Death Star hologram are particularly interesting to me, since they seem to indicate that the soft focus is in fact deliberate (or at least unavoidable during actual filming), and not a limitation of the transfer process used at the time. If the 35mm theatrical prints were simply low quality, I wouldn't expect the subtitles or the Death Star hologram to show any fine details, but the subtitles are pretty sharp compared to the rest of the image, and the lines of the Death Star holograms reveal some pretty minute gaps between them in places.