logo Sign In

Practical Image Resolution of Film

Author
Time

There have been a lot of images of film scans shared and from them I am trying to determine what the practical resolution (as in how much fine image detail there is) exists at each stage. There is the original camera negative (for the Star Wars movies shot on film, that would be 35 mm for most shots and the Vista Vision cameras for the effects shots), then the Interpositive, the Internegative, and the distribution prints. Plus the 3 color separation master and the Technicolor prints. The bluray master was scanned from the original assembled negative. The 2006 GOUT seems to have been from an original Interpositive. The JSC seems to be from something further down and the TN1 Silver Screen edition is from 35 mm distribution prints. Mike Verta is working from a 4k scan of a Technicolor print.

From what I’ve been able to gather from the images that have been shared, the Technicolor prints seem to have less detail than the bluray and are closer to 720p. The 35 mm scans go down further. After all, they are a copy of a copy of a copy of the original so the grain has been amplified and the details muddled. It is the nature of analog copies. Even so, I come up with a resolution of 540p (half HD), so you get more detail than any DVD.

Now I know that film preserves a lot of other information, such as grain, but things like hair and detail lines are what I am looking at. I’m curious if anyone has done a more accurate examination.

Author
Time

Are you just talking Star Wars? Because film != film… the actual filmstock is extremely highly variable, as are the optics at both the camera and projection ends. Very good filmstock with very good optics yields detail that IMO can exceed 2K even in the theatre. Regarding Star Wars, I believe Technicolor is one generation earlier than a typical opening-day projection print, and I believe the Silver Screen print was a dupe print, meaning it was actually one generation later than a typical opening-day projection print. Also, I’ve heard that 70mm blow-ups of 35mm prints, once projected, still show more detail than the 35mm prints they’re derived from, which is a little counterintuitive for people coming at it from the digital world.

Project Threepio (Star Wars OOT subtitles)

Author
Time

Well, I think it best to ignore the entire projection system an focus on the film. There are too many variables that can reduce detail. Just considering the film itself, I thnk, will give a more certain answer.

I have access to very little, but what I do have is Star Wars EPS 4, 5, 6, and 1. I know Team Negative 1 had access to several prints so I’m not sure it is accurate to refer to their two offerings as single prints. I can see differing resolutions in A New Hope so it may be that they had to use some from a lower quality copy. But generally those are effects shots. The test is pretty consistent between grain and detail between ANH and TESB, and even Harmy’s ROTJ. I have not done an exhaustive comparison, just some basic ones on frames I have from multiple sources. That led to my above conclusions, but I’m hoping others have looked into it more.

While grain is fine in the final product, with each generation grain as well as the optics of the duplication process degrade the fine details. I’ve noticed that grain can hide some of the data loss in the projects on here. If you add grain to the GOUT it looks higher quality. That’s one of the things Harmy did on the Despecialuzed Edition.

Author
Time

Imo, with 35mm you will NOT get much detail beyond 1080p, and with 70mm, you will NOT get much detail beyond 4K. This is AT BEST.

Author
Time

Imagine It Entertainment writes:

… just how much information is actually on film … The following images are a simplification to illustrate some general points. … and will vary based on specific film stocks.

• • 8mm and Super 8 film has a maximum resolution of 2K horizontal lines. • • A 480 line SD scan will only get about 40% of the details from the film. • • A 1080 line HD scan will get about 75% of the details from the film. • • To truly archive 8mm or Super 8 film it must be scanned at 2K resolution.
• • Older 16mm print film has around 2K lines. • • Newer 16mm and S16mm can have up to 3K lines of resolution. • • Although an HD scan is good, it only gets about 50% of the details from the film. • • To archive 16mm film a 2k scan is required for older print film and a 4K scan for newer film stocks with smaller film grain.
• • Older 35mm film has up to 3K lines while newer 35mm film can have in excess of 4K lines. • • An HD scan only gets about 1/4 of the film’s details. • • A 2K scan (2048 ×1556) will get about 50%. • • A 4K (4096 x 3112) scan will get the majority of the film details. Newer film stocks with finer grain will require a 6K scan in order to truly archive it.
Author
Time
 (Edited)

junh1024 said:

Imo, with 35mm you will NOT get much detail beyond 1080p, and with 70mm, you will NOT get much detail beyond 4K. This is AT BEST.

Not true, but the real answer is complex.

On some of the Star Wars 35mm prints I have scanned, there is plenty of detail at 4K that just isn’t there, and in some cases, cannot be there at 2K/1080P.

If you resize the 4K scan to 1080P that detail is lost, the classic example is the door seal on the Tantive at the opening of Star Wars (Ep IV). On the 4K scans you can see the ridged detail, on the Blu-ray and any 1080P source, it is a non-descipt grey.

However, the Blu-ray, even in that same scene shows some detail not in the 35mm prints and yet is missing detail from the 35mm prints at the same time

So what is going on?

It is down to transfer. When you scan from the neg, you pick up all sorts of detail that will never make it to a print, and some of this survives the down-rez to 1080P, so the Blu-ray is more detailed in some areas than the prints. Yet there is some detail that is simply finer than 1080 lines, so can never be seen on any 1080P source, uncompressed or otherwise, yet will show up nicely on a 35mm print.

So the answer is… it depends.

There is definitely detail on the Tech IBs of Star Wars, that are well above 2K, but if your final delivery is 1080P, then it probably doesn’t matter. If you want to make a UHD/4K version for viewing on your snazzy UHD/4K TV however, then that detail can be retained if you scan at 4K or higher.

I tend to scan at a vertical resolution of 3400 pixels or so, and that seems to retain all the detail from the 35mm prints, dropping to 2160 pixels vertically definitely loses some visual detail, so I won’t scan archivally below 3000 pixels, but if your delivery is 1080P, then you could probably scan at UHD resolution, and end up not seeing any difference.

That is all talking about 35mm prints. A 35mm neg however easily can have detail that exceeds 4K, but again, unless your final delivery is better than UHD resolution, then you may not need to scan any higher than 4K full aperture.

Donations welcome: paypal.me/poit
bitcoin:13QDjXjt7w7BFiQc4Q7wpRGPtYKYchnm8x
Help get The Original Trilogy preserved!

Author
Time

A 70mm print scan would be freaking awesome

Palpatine: Make the galaxy great again!

Author
Time
 (Edited)

Thanks for your detailed reply poita. I’ve gotten an opinion from another source that 35mm is worth somewhere btw 2K - 4K. I’m not totally convinced that 35mm is worth > 4K though. How much of the detail is actually just noise/grain? Or is it a personal decision?