A few quick points on 'HD', DVD and film.
Film holds a far greater colour depth and a far greater resolution than DVD - this is true of 16mm and exponentially more so for 35mm. Even Super8 holds far more colour resolution than DVD.
For a start, DVD is 4:2:0, even consumer HDTV (1080i or 720p) is only 4:2:0 so your colour resolution is horribly, horribly compromised compared to film where there is effectively a 1:1 resolution match for colour to picture information.
A good quality theatrical print can easily resolve greater than 4000 lines of detail. You can point a camera at a 4K test pattern and actually resolve 4000 lines on the film, you certainly cannot do that with DVD. Weave reduces the resolution of film, but it is still way higher than 2000 lines.
Lucas didn't shoot on digital because he believed it was 'better quality' than 35mm film, but because it saved an estimated 1-2 million dollars in film stock costs (compared to digital tape) and also was 'ready to go' into post production, which saved a fortune on scanning costs and time, which is a big deal on a effects heavy feature like a Star Wars movie.
Also, when you say Lucas shot the prequels on HD, we are not talking conumer HD (i.e. 4:2:0 1920 x 1080 interlaced and heavily compressed.)
Even the aging Sony cinealta 950 camera captures colour in 4:4:4 RGB, and it is really old hat these days. The newer arri rigs shoot uncompressed 4:4:4 at over 3000x2200 (I can't remember the exact rez) in 12 bit colour (actually colour is better than that via the algorithms they use).
The newer SXRD Sony projectors used in digital cinemas run at 4096x2160 , although the early projectors were 2K (and IMHO look pretty ordinary).
In short, even 16mm film leaves DVD in the dust quality wise.
"If they transferred it again, and only removed large, visible, obvious deformities - it wouldn't be that different to the 1993 master, even if it was scanned at 720p or 1080p."
This is something a lot of people incorrectly assume.
If they fed the OT through one of the new arriscan machines, it would look immeasurably better than the 1993 transfers.
Just look at the extra detail in the newer scans of the OT used for the 'official DVD' vs the laserdisc transfers - even if you scale them down to 277 lines they have a lot more detail than the laserdisc or the D2 tapes. This is because of advances in scanning technology, and because the film holds more resolution and colour than any DVD of HD-DVD/BluRay format is capable of holding.
That is one of the beauties of shooting on film vs on digital. When attack of the clones was shot, 1080P was as good as you could get with a digital cine camera. Because they used that format, all of the elements shot on it are stuck at that point in technology, forever.They will never be able to get a 4K or 8K image with 16 bit colour out of it, because it is a 1080P master.
If they had shot it on film, then as scanning technology improved, so could a digital transfer. Had they shot AOTC on pin registered 35mm they could scan it today and get a 8K master with 4:4:4 12 bit colour, and it would have a lot more detail than the 1080P master they have now.
"Even at "laserdisc resolution" (roughly equal to non-anamorphic DVD) you can show a movie theatrically."
Um no - you really really can't. Even on a 10foot wide screen the 277 lines or so of a scope laserdisc looks appalling, you have to run it through a good scaler to make it even watchable. On a theater screen it would be a total joke.
Full frame DVD resolution (720x480 NTSC) is also a block-fest on a theatre screen, each pixel on a 24 ft wide screen is around half an inch wide (1.2cm or so) . You can scale it and so forth, but it still doesn't look any good.
Even for a good home theatre projector like a Sony G90 standard DVD is almost unwatchable unless you scale it up first, and even then DVD through a great scaler looks crapola compared to a decent HD-DVD or DTheater title at 1080i.
(BluRay doesn't look much better than DVD at the moment as it is currently only single layer and MPEGII - what on earth is Sony thinking?!?!). So no, a non-anamorphic DVD transfer could not be shown theatrically - it will look awful.
Moving back onto the thread topic
The problems for a preservationist looking at a film transfer however are a multi headed hydra.
As pointed out the sheer number of frames and storage is daunting.
172,800 frames for a two hour film. Scanning, processing and saving a frame every minute (which seems reasonable including stabilisation and super basic cleanup and reassembly into a 'movie' file) equates to 360 days of working 8 hours a day, 7 days a week.
Then there is the quality of a surviving print. 35mm prints of Star Wars were *never* offered for sale. Ever. This means any surviving print was stolen or *ahem* obtained. It also means that unless it was stolen extremely early in the piece, it went through the projector a *lot* of times. This was a popular movie folks!
It also means the print will be well over 20 years old. Any Eastman prints will now be pink. There will be surviving prints on other stock with the colour in good shape, and perhaps even ones that have not been through a projector more than 20 or 30 times, but they will be beyond rare.
Even if you got hold of one of those ultra rare prints, they will still be covered in an unimaginable amount of dirt, scratches and crud. What a collector would consider a 'mint' print will look very dirty under a scanner, and will require extensive cleanup. A 'good' quality print would need nearly every frame touched.
I don't own a 35mm print of SW, but have had access to some in the past, and while they were useful as a colour reference, none would have been good enought for a high quality scan.
Legality. I've been in the industry a lot of years, and I don't know *anyone* who would scan a 35mm print of Star Wars that is working professionally. They wouldn't just be risking their job, they would be risking their entire career.
They would also be risking a gaol term. If the print got into the wild, I'm pretty sure Lucasfilm would put a lot of resources into tracking down where it was done. They are quite forgiving of the 'home' user making his own versions and playing with laserdiscs, but if a film facility scanned a print I'm pretty sure all hell would break loose. (Speculation on my part of course)
It isn't point and shoot. Scanning a film isn't a 'put it an and press the button' proposition. Even a straight telecine requires tweaking almost on a scene by scene basis to get a good result from a print and not a neg. Scanning is even worse.
Newer scanners like the arriscan out at Weta make the job a lot easier, but there is still a lot of work to do. Even just getting the LUTs right is an artform.
It also means that it would be difficult for an employee to just 'run it through the scanner' during downtime (even ignoring that most scanners keep a frame count of frames scanned too, which is used for costings, maintenance etc. and a few hundred thousand extra frames gets noticed). It takes a lot of setup and work and is hard to do 'on the quiet'. You can get away with scanning your 5 minute short film project, but 6 or more reels of 35mm is hard to stuff up your jumper when people look in your direction. It is also hard to use up that much disk storage without being noticed, and then smuggle the files and film reels back out again.
None of the above means it is impossible. I reckon it is impractical and improbable, but I've been wrong many times in the past.
I still can't believe that Lucasfilm didn't scan all of the original camera negs, or that they cut up the original negs with new footage - it would be an act of vandalism to do so, but if he believes it is his film and he can do what he likes with it, there would be nothing stopping him just setting it on fire if he wanted to I guess.
So in short, if you are still keen then locating a print is the first step, and checking out the quality.You really can't get anywhere without a decent print or two to work from.
Step two would be to keep it to yourself lest Lucasfilm come after you to get their print back (it will still belong to them under the law I would think, and it wouldn't be the first time privately held 35mm features where 'recovered' by a studio).
Then look at what would be involved with getting a transfer done.
(BTW. a huge thanks to everyone here, I'm not officially back, and promise not to take this thread any further off topic - but I borrowed a computer and thought I'd drop in and say hi. Hopefully I'll be back properly in a couple of months and will rejoin the fray.)