ESB was released during a dark time in-between Technicolors and LPPs. Almost all prints have faded brick-red including the ones poita is scanning. A handful of prints were struck after release on LPP as mentioned by poita.

How did they turn up in the first place? It costs quite a lot of money to ship prints around the world, so studios often didn’t care to have them returned after their theatrical runs. So they would be either disposed of or kept by cinema staff turned collectors.

TN1’s “Silver Screen Edition” (Star Wars, not ESB) was based mostly on a Spanish LPP which was a dupe made from a print. So no it wasn’t the best available, but that was a different project to poita’s.