IMAX DI Scans

[Ari Michael Leeds]

That's only for the SFX. The IMAX was contacted printed unless there was CGI involved.


I am speaking of the IMAX prints. They optimized for both 35mm and IMAX portions with each respective projection format. Hate to say it, but never saw Dark Knight [&-rises] in 35mm, only IMAX, for each.

Edited March 17, 2016 by Ari Michael Leeds

[Scott Pickering]

Interesting info guys. If I was building an IMAX theater today, I'd try to get an 8K laser projection in there. But the technology isn't there just yet. Getting there though. I imagine by the time its ready, many of the 2K IMAX screens will convert by then. Still nothing looks quite like film projected instead of what we have now which is basically high rez video.

[Ari Michael Leeds]

But 8K is less than half the resolution, Scott. . .

[David Mullen ASC]

IMAX film print projection isn't 16K resolution anymore than a 35mm projected print achieves 4K resolution even if you believe that the negative resolves 4K (personally I think 35mm negative resolves a bit more than 3K, but that suggest it should be scanned at double that resolution according to Nyquist).

 

Most people feel that a good contact print projected maybe achieves half the resolution of the negative, which is why 2K projection seems on par with most print projection in terms of resolved detail. However, as people sit closer to the screen, one can argue that seeing visible grain is less distracting than seeing visible stair-steps along edges, which is one argument for 4K projection.

 

Anyway, we were talking about IMAX. Since when we use terms like "4K" we are just talking about horizontal dimensions, and an IMAX frame is about 3X the size of a 35mm frame, then if you believe 35mm negative resolves 4K than an IMAX negative should resolve 12K, but this also means that a projected IMAX print probably resolves about half of that, meaning that 6K to 8K digital projection from a 12K scan of 15-perf 65mm negative should be similar in terms of detail on screen.

[Tyler Purcell]

Yep, David is 100% right with his numbers.

 

15/70 IMAX on screen is slightly north of 8k. Unfortunately there is no 8k distribution format for digital. So even though IMAX does have a double laser projection system which fills in the gaps between each others DLP imager, making a faux 8k, the source is still 4k at most.

 

IMAX has been working on an 8k delivery format, but as you can imagine, it doubles the bandwidth, so the server required for playback needs to be a lot more robust. When they do accomplish that task, it will be the best projection system available today. It's unfortunate they dumped film so quickly because the last iteration of film projectors were absolutely amazing, but they went 3D and that upped the price and created too many limitations.

[Peter Bitic]

 

Most people feel that a good contact print projected maybe achieves half the resolution of the negative, which is why 2K projection seems on par with most print projection in terms of resolved detail. However, as people sit closer to the screen, one can argue that seeing visible grain is less distracting than seeing visible stair-steps along edges, which is one argument for 4K projection.

Yeah, I like to sit close to the screen and I have noticed pixel grid in 2k projection. Wouldnt the easy solution to that problem be to use a softer projector lens that can "output" slightly less than 2k?

[Doug Palmer]

Yeah, I like to sit close to the screen and I have noticed pixel grid in 2k projection. Wouldnt the easy solution to that problem be to use a softer projector lens that can "output" slightly less than 2k?

But then the pin-points of stars etc would look bad. The titles also would look too soft, although I do hate seeing those staircases on diagonals.

[Tyler Purcell]

They do soften the projector already, most projectionists I've talked to have admitted to running focus softer to help remove the aliasing and crispness issues associated with digital cinema projection.

[Landon D. Parks]

I would also add that no one has really defined 'IMAX' here. Cineplex IMAX (lymax) screens are no where near the size of an original IMAX screen. In fact, they are not much more than 10% larger screens stuffed into a standard auditorium with seats moved closer to the screen and a beefed up sound system.

 

Honestly, I feel anything other than the typical museum IMAX is a waste of money.

[David Mullen ASC]

The sad thing is that even for the classic science museum IMAX theaters, there are fewer and fewer productions shot in 15-perf 65mm. The last science documentary I saw in an IMAX theater was a mishmash of formats, mostly digital, and only a few minutes of 15P footage.

[Tyler Purcell]

The last 100% 15/70 film that I know of is "Rocky Mountain Express", which was made in 2011. If you do some research, you'll see most of the films made from that point on, were mostly shot digital.

 

It's one of the best 15/70 films ever made.

[Ari Michael Leeds]

David: You are making a math error. As we are talking about area, 16K is FOUR times, not twice 8K.

Unlike digital, it's completely unnecessary to exaggerate the credentials and the resolution of IMAX 15/70 B)

[Ari Michael Leeds]

If you have a contact print, a show print from a 15/70 negative, before it goes through the projector lens mind you (see a 4K projector isn't 4K either as the chip goes through a lens too B) ) that's gotta be at least 10K on the film.


My understanding is there is 50% loss whenever you go through a lens. So, with only 5% or so better on the 2K files than the BluRay, if we wanna get really technical, the BluRay doesn't go through a lens, and even with compression, would be a better resolution than the 2K DCI through a lens.

[David Mullen ASC]

Err, you're the one making a math error since "K" only refers to horizontal resolution not total area. If an IMAX frame is 3X the horizontal width of Super-35 then a 12K scan for IMAX would be the equivalent of a 4K scan of Super-35.

[Ari Michael Leeds]

But where did I say 16K? And where did you get that from 8K?

If you noticed, I said 11K or 12K. So a contact from that, pin registered, would have, IDK 10% loss? Certainly not anywhere near as much as optical printing.


8K is 1/4 the resolution of 16K, just like 2K is 1/4 the resolution of 4K, assuming the same aspect ratios.

[David Mullen ASC]

I see what you are saying now though I disagree that 8K projection would only be half the resolution of IMAX print projection.

[Ari Michael Leeds]

Oh, OK, sorry, I see what you are saying and which of my comments now.


What sort of resolution do you think that an IMAX print has, a contact from the OCN?


Keep in mind, 8K with digital still goes through a lens, so comparing IMAX on the screen to the digital chip before it goes through the lens is apples and oranges.

I'm operating off the assumption that an IMAX contact is 10% less than the negative, greater than 10K. Maybe slightly less than double. I'd have to go in and look at the square root of two myself. Not that good at math :-D

[David Mullen ASC]

I'm just scaling up from what we know about regular 35mm print projection vs digital projection.

[Ari Michael Leeds]

Roughly 11.2K would be double res., so maybe that's a little bit more than a show print contact.


But, most people look at Ks and are misled, kinda like with film speeds, 1000 is only one stop more than 500 just as much as 50 is a stop more than 25.

This is one area where I wish cinema would follow the lead of still photography and stick with megapixels.

Edited April 17, 2016 by Ari Michael Leeds

[Tyler Purcell]

You can convert K to megapixel very easily. Just multiply the two H and W resolutions and you get megapixel.

The industry uses "lines" because that's how we determine resolution with film, you can't do it any other way. Megapixel is a factor of the digital age when you can count the active pixels on an imager grid. Since film's silver makeup is random, it's impossible to get a megapixel count from it. All we can do is project a still image onto a screen and count how many lines we see from the photographed chart.

 

What I do know is that projection lenses play a HUGE role in this process and digital is no different. So a 4k imager of a digital projector is NOT delivering 4k to the screen. However, since film is a projected format, it seems irrelevant to discuss actual resolution, since nobody will ever see it. The only thing that matters is what the film looks like when projected.

 

What I'd be interested in seeing is a test with modern projectors to see what resolution is visible by the audience. 35mm release prints (4th gen) are generally less then 2k in of themselves. When projected on screen, perceivable resolution is somewhere in the 700 - 800 line range. Is 2k digital any better? Well, I would assume so because even the worst digital appears to be crisper. Plus, with 35mm projection, there are many issues that cause the film to be not as crisp, from gate weave, out of calibration shutter and old glass.

 

I recently saw Batman v Superman, a horrible movie that was on the borderline of unwatchable. Yet, it was a absolutely gorgeous 5/70 print which was the reason for going. I sat mid theater, the screen was huge and it looked better then any digital projection I've ever seen. No registration issues, no flicker, no dirt, no noticeable splices, no aliasing which is typical of lower resolution projection. Now obviously I saw it at the Arclight and yea, they have a DP70 up there, which is one of the finest film projectors ever made. Still, it was worth the experience to see such a wonderful projection of a horrible movie. It does show that 5/70 is still the best standard projection format around and 15/70 blows the doors off 5/70, it looks very digital it's so clean.

[David Mullen ASC]

Trouble with megapixels is just that it requires you know the aspect ratio, i.e. specify the height.

 

I don't think the projector lenses are very limiting for resolution, otherwise you wouldn't be able to resolve the grains in the print, and detail on the print is limited to grains, and otherwise you wouldn't be able to see the grid of the 2K or 4K pixels if you got close to the screen, and you can if the projector is focused properly. Most of the resolution loss from the 35mm negative happens in the duplication steps to a release print.

 

Most people who have done tests over the years basically find that 35mm print projection barely shows 2K on the screen. But the advantage of 4K projection for 35mm material is that you can show more of the detail that was in the original negative than a 35mm release print can, but you won't be aware of the pixel grid pattern if sitting one-third back from the screen. So there are a lot of arguments for 4K being the standard for cinema projection (as a replacement for 35mm projection). And 4K projection has a similar feeling to 5-perf 70mm print projection, ignoring issues such as black level, which tends to be superior for film print projection (and good black level has the advantage of creating the feeling of better sharpness and richer colors.) I've seen good 70mm print projection that feels like digital projection, the image is so clean and steady.

 

So in my mind, ignoring the issue of what the best resolution is for mastering, 2K digital projection is similar to 35mm release print projection in terms of detail visible on the screen, 4K would therefore be similar to 5-perf 70mm, and 6K or 8K would be a good match for 15-perf 70mm IMAX print projection. However, that's a very crude way of looking at things, merely in terms of the ability to resolve fine detail, and ignores a host of other image characteristics such as black level, contrast range, color depth, steadiness, cleanliness, etc. One could build a theoretical 8K IMAX digital projector and still find the image less pleasing than 15-perf 70mm print projection even if the detail resolved is similar.

 

For me, IMAX print projection contact-printed from 15-perf 65mm material is a gold standard that has yet to be matched, and it's a shame that we are losing it before any adequate digital replacement has arrived, just as it is a shame that we done see more 15-perf 65mm photography being done.

[David Mullen ASC]

I actually enjoyed "Batman Vs. Superman", but in particular, I enjoyed Larry Fong's cinematography. I liked how there was less desaturation of the blue & red Superman costume in this new one, and less handheld work.

[Tyler Purcell]

Did you by any chance see the 70mm print at Arclight?

[David Mullen ASC]

No, wish I did.

[Tyler Purcell]

No, wish I did.

Dang! I should have been more vocal about seeing it. By far one of the best film projection experiences I've had. I was gitty for the first 20 minutes. :)