I think that polaroid shots were taken as well with those old instamatic cameras. I have about 20 of tiefighters,x-wings and the death star. Sadly they have not withstood the test of time. I'm sure these would have been used on set for pure convienience.
I believe most of those official publicity shots were shot with a 4x5 camera. For marketing purposes, that is really the best way to go as the image is superior to regular 35mm. Also, you can do multiple exposures with a large format camera that would be difficult to do with a 35mm. This allows you to get all the lights and fiber optics on the same negative without having to go through optical.
Part of that process is to take a B&W Polaroid to check the lighting and exposure. So, those are essentially a B&W copy of the publicity still, yet still an original. (Kubrick used this method extensively on 2001 in order to get an idea of what a shot would look like on a piece of film.) Some Polaroid film is better than others. I've seen some stuff going way back that is every bit as crisp and clear as the day it was shot.
As for the personal photos, most of the guys shot short ends of the motion picture stock they were using to film the models. You try to avoid a roll out on a motion picture camera, so you stop filming and are generally left with small rolls of unexposed film. That film can be loaded into the small canisters and then shot with a regular 35mm camera. You can't get it processed at the local Fotomat (remember those?) since it used a different chemistry than the C-41 process stuff we civillians use (well, used). It had to be sent to a lab in Hollywood called RGB. They would develop the negative and return it with a set of slides that were mounted in the regular cardboard sleeves. When you got the negatives back, you could then send them out and have prints made. but most of the ILM guys seemed to go the slide route. The problem is that the slides were printed onto standard motion picture workprint stock and the stuff is not color stable. Over the years (and actually very quickly) the image begins to degrade. Mostly they wind up losing contrast and looking magenta (purple). Some of it can be color corrected, but the image quality still suffers. The good news is that the negatives are fine if stored properly. I've seen scans from original negatives from the "Galactica" days shot on the same stuff and it looks like it was shot with a nice digital camera just yesterday. The bad news is that all too often, the negatives got lost.
Like I said before, the guys shot a lot film on this show - most of which wound up in the archives. I got to use some of it for Lorne's booksigning here in LA and I noticed that some of the imagery they gave me has now wound up in that book. Also, the next issue of Sci-Fi and Fantasy Modeller (the British mag) will also be printing more of those rarely seen photos. That's cool as there is a ton of it that hasn't been seen in many years.
Gene