I saw it last night, and posted to the RPF. Here’s a summary:

The screening of the original 35mm UK release of Star Wars at the BFI was fascinating. The opening, with the ugly green Lucasfilm text, and the original 1977 title crawl (no bloody A, B, or ANH) was fun.

It’s interesting how many people were laughing at all the cheesier lines of dialogue, making me wonder how many people had never seen the film before. In fact, there seemed to be two categories of audience members - those laughing like they’d never seen the movie, and those laughing at all the original things to the film. And some scumbag who laughed when Red 6 dies.

In terms of the film’s appearance, the colour looked pretty decent, but overall low-saturation and not terribly bright. Since it was one of the last 35mm Technicolor (process 5) dye prints made in the UK before the facility closed, it hasn’t suffered from the awful colour collapse of an Eastmancolor print. But what a reminder of how even big 35mm film releases looked at the time. It was very soft, low contrast, grey blacks… not the sort of high-contrast crisp sharpness you get from a digital projection! Some dust and scratches of course.

Oddly the print looked to me to be slightly cropped to the top and left sides - not sure what that was about. The credits were noticeably off-centre.

Anyway, this meant that a lot of scenes which look visually problematic today, such as contrast issues in the Blockade Runner footage, the hard lighting of the “your home planet of Alderaan” scene, the visible difference between Luke’s face and neck makeup during the Yavin base scene, etc, were kind of concealed. But interestingly the Tunisian footage still looked soft and kinda bad - the idea of putting stockings over the lens really didn’t work!

As for the sound, which was two-track stereo optical, it definitely had that kind of muffled quality that was normal for the era. Pre-THX or Dolby Digital sound. We really are spoilt by digital audio, that’s for sure.

Interestingly the effects looked great - you can see how even the dodgy matte paintings (especially the Death Star docking bay from above, the matte painting above the Cardington footage of Yavin, the set extensions for the closing ceremony scene) and optical issues really weren’t that bad for the most part - they really were designed for 35mm projection. There were no visible garbage mattes around the ships, the way they were on video. The main noticeable technical flaws were spacecraft interior bluescreen shots, like the Falcon cockpit, which always looked pasted on. And the wide shot of the Death Star lift shaft had a ton of halation on the live action side.

Still. I was really struck by how the effects shots during the final battle looked pretty awesome, even without CGI bells and whistles.

For people wondering about details of the print:

During the introduction the BFI team said that the screening was approved by Lucasfilm/Disney, and that Kathleen Kennedy had been at the BFI earlier in the day.
Of course, none of the digital-era changes we’re used to are there. The Greedo sequence, the chasing the troopers in the Death Star sequence, no Death Star explosion shockwave, etc. etc. Obviously.
As noted, this was the original 1977 print. The BFI found the print with the “ANH” title crawl spliced on, but the original 1977 Star Wars-only crawl had amazingly been stored in a separate can after being removed. So they cut off the ANH crawl and spliced the original one back. It’s great how the score’s timing perfectly matches the appearance of the first moon and the curve of Tatooine.
3PO doesn’t say “we’ve stopped” before whacking R2 on the head inside the sandcrawler.
A few frames were cut out towards the end of the garage sequence. Pretty sure those were just caused by damage on that particular print, not an intentional edit. This caused the sad R2 beep after “I don’t like you either” to be missing.
Since it’s the stereo release, Beru’s brief dialogue is the original looped Shelagh Fraser dialogue, as heard in the SE.
The troopers who search the Falcon don’t say “there’s no-one here”.
3PO’s narration during the “the tractor beam is coupled to the main reactor in seven locations” sequence is not present since it was added for the mono mix.
Craploads of echo on the voices during the “I think we took a wrong turn” scene in the Death Star trench.
The “Close the blast doors” line isn’t there since this is the stereo mix.
The more pronounced shortwave radio effect on the pilot voices heard in the Rebel base.