I have found first hand info on what prints were used for the CBS/FOX telecines. 1982 transfer of Star Wars was a release print. The initial releases of TESB and ROTJ were interpositives as was the concurrent release of Star Wars. The 1985 release of the trilogy was also interpositives. Tapes were sent to Lucasfilm, but no one from Lucasfilm was present. And it seems that virtually all films telecined at the CBS/FOX facility were either interpositives or internegatives. One exception was a collection of Chaplin films.
Not a single special telecine print. Not a single 16mm print. And done on a Rank Cinetel 2.
The interview with Wayne Cook can be found here - https://www.youtube.com/watch?v=2LagwssLxlk
Sure but how many times did they use a release print? Once out of all their domestic home video releases by the sound of it. But what about their foreign releases? The French release? Japan? Australia? Germany? I can just about guarantee you they were not using release prints for all those releases.
It doesn’t surprise me they used the IP for other releases, like I already said typically for home video you use a low-contrast film (anything but a projection/release print) as that’s what telecines are designed to transfer. The IP is less valuable than the cut camera negative, and often less beat up than the duplicate neg (the interneg) used for striking release prints so it makes sense to use it.
But now you have to explain to me why those releases have negative cue marks in them. Because if they were from the IP that means the cut camera negative (or the o-neg) had cue marks etched into it. To me that doesn’t exactly add up…