I’m watching the Rogue One bonus featurettes and during the K-2SO one they showed a clip from the original film that didn’t look like the blu ray. It’s R2 and 3PO on the Tantive and I think it looked better than the blu, but it’s been a while since I’ve looked at the blu.
Clip of Tarkin/Leia from SW77 was just shown in The Empire featurette. It looks better that the blu as well, but again, this is just based on my memory.