Film-Tech Forum ARCHIVE: IMAX

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Posted by Haris Ellahi (Member # 9941) on 05-12-2019, 01:11 PM:

I am not sure where to ask these questions so I am going to try to ask them here...

1. What exactly is IMAX DMR? Does it only have to do with picture/image "optimization" or does it also "optimize" sound?

2. Does each and every movie shown in a IMAX theater go through this DMR process?

3. For movies that are not shot on IMAX cameras and also do not have a IMAX-specific audio track, how are they played in IMAX theaters? For example, Godzilla: King of the Monsters is shot in scope and only has a Dolby Atmos sound mix according to IMDb. Since this movie will also be played in IMAX theaters, what is done to make it "compatible" with IMAX theaters (specifically the sound mix since IMAX theaters do not use Dolby Atmos)?

4. What does "Optimized for IMAX Theatres" mean? Spider-Man: Into the Spider-Verse has this logo right at the end of the end credits along with the "Dolby Atmos + Vision" logo. Spider-Man: Into the Spider-Verse was shot in scope format but has a 12-Track Digital Sound audio track for IMAX theaters (along with Dolby Atmos for theaters that utilize Dolby Atmos). Since it has an IMAX-specific audio track, does this let the movie "earn" the "Optimized for IMAX Theatres" logo or are there other things that also factor into this?

Posted by Daniel Schulz (Member # 1881) on 05-12-2019, 01:41 PM:

quote: Haris Ellahi
I am not sure where to ask these questions so I am going to try to ask them here...

1. What exactly is IMAX DMR? Does it only have to do with picture/image "optimization" or does it also "optimize" sound?

Originally referred to the process to convert standard Hollywood movies to IMAX 15/70, usually with some form of grain reduction and some other image enhancements to ensure the picture looked good when blown up to IMAX-sized screens. With the rollout of smaller screens and now digital projection, they are still using this term to refer to the IMAX re-mastering of the picture, again to optimize how the image looks when played back on IMAX systems. Nothing to do with optimizing sound.

quote: Haris Ellahi
2. Does each and every movie shown in a IMAX theater go through this DMR process?

Movies produced natively with IMAX cameras do not need to undergo the DMR remastering, although I would imagine that the post workflows for a remaster and an IMAX original are similar, in terms of the target requirements for color grading and so on.

quote: Haris Ellahi
3. For movies that are not shot on IMAX cameras and also do not have a IMAX-specific audio track, how are they played in IMAX theaters? For example, Godzilla: King of the Monsters is shot in scope and only has a Dolby Atmos sound mix according to IMDb. Since this movie will also be played in IMAX theaters, what is done to make it "compatible" with IMAX theaters (specifically the sound mix since IMAX theaters do not use Dolby Atmos)?

See below: if playing in an IMAX theatre and advertised as an IMAX release, both the picture and sound are massaged for IMAX playback.

quote: Haris Ellahi
4. What does "Optimized for IMAX Theatres" mean? Spider-Man: Into the Spider-Verse has this logo right at the end of the end credits along with the "Dolby Atmos + Vision" logo. Spider-Man: Into the Spider-Verse was shot in scope format but has a 12-Track Digital Sound audio track for IMAX theaters (along with Dolby Atmos for theaters that utilize Dolby Atmos). Since it has an IMAX-specific audio track, does this let the movie "earn" the "Optimized for IMAX Theatres" logo or are there other things that also factor into this?

For movies playing back in IMAX theatres and advertised as IMAX releases (often with an Optimized for IMAX logo in the credits) there is both a DMR remaster of the picture and an IMAX remix of the soundtrack, for playback on the IMAX 6 or 12 channel sound systems. Often the IMAX mix is derived from the original Atmos mix, but it is a true remix with creative input and control over the IMAX version of the soundtrack.

Posted by Bobby Henderson (Member # 840) on 05-12-2019, 02:49 PM:

Regarding IMAX DMR: the DMR term is essentially meaningless anymore. It was primarily a method of blowing up Hollywood movies on 35mm film to the 15/70mm film format. Apollo 13 and the two sequels of The Matrix were early examples of this. Back then most Hollywood movies were still shot on film and virtually all IMAX theaters were showing movies on film. American theater chains like Cinemark were installing 15/70mm projection systems to be able to show these DMR 15/70mm blow-ups of Hollywood movies. IMAX figured they could get a lot more multiplex theaters to get on board with IMAX if they developed a digital projection system.

Since then Hollywood has largely transitioned to all-digital production. And the vast majority of theaters bearing an IMAX logo have the ordinary 2K resolution dual Xenon-projector setup and 6 channel audio. Most of those theaters are more modest sized rooms in commercial multiplex theaters. Many classic IMAX theaters in places like museums have either closed or replaced their giant format film projectors with digital projectors.

Very few Hollywood movies are shown on 15-perf 70mm film prints anymore, and of the very tiny number that are shown on 15/70mm film they're usually a passion project from Christopher Nolan and largely shot on 65mm film negatives (in 5/65mm and 15/65mm format). There's very little to "DMR" for IMAX there. And there is no point in trying to "DMR" a Hollywood movie that will be shown in 2K resolution IMAX digital theaters.

Regarding IMAX sound: extremely few IMAX-branded theaters have the 12-channel sound system. The 12-channel sound system is found exclusively in IMAX with Laser theaters. Those theaters have the very expensive 4K resolution dual laser projection setup. Apparently it costs around $2 million to swap out an existing IMAX projector setup and install the new laser-based one. Such installations are usually only taking place in some former 15-perf 70mm film-based IMAX theaters. Most film-based IMAX theaters have had the film projection systems removed and replaced with the ordinary 2K dual projection Xenon-based setups.

There are no Dolby sound formats in IMAX theaters. They don't have "Dolby Surround 7.1" (a re-branding of the "generic" LPCM 7.1 format) and IMAX theaters certainly do not have Dolby Atmos.

I used to be pretty excited about Dolby Atmos when it was brand new and a few movies were released (such as Gravity) that made excellent use of the format. Since then I've been fairly disappointed. Far too movies I've gone out of my way to see in Dolby Atmos theaters have had very mediocre mixes. It's as is they post production crews just mixed the movie in regular 5.1 or 7.1 and put an Atmos label on it. Given the very short amount of time sound designers and mixers typically have on a given project it shouldn't be surprising many Atmos mixes are barely any different from a 5.1 mix. This problem is compounded by the wide range of choices theater operators have on equipping an Atmos auditorium. Configuring a great Atmos system is a very expensive proposition. Exhibitors can reduce the number of amplifiers, speakers and other equipment that go in to an Atmos system to greatly reduce costs. But they still get to stick "Atmos" on the marquee anyway. And that's assuming any customers care in the first place.

When it comes down to it, I really miss the THX theaters from 25 or so years ago. Back then the theaters were trying to at least meet some clear standard.

Posted by Haris Ellahi (Member # 9941) on 05-12-2019, 03:25 PM:

Thanks a lot for the detailed replies!

Would you guys recommend watching Godzilla: King of the Monsters in IMAX with Laser (and the 12-Track sound system) or Dolby Cinema? I have both available to me.

Posted by Marcel Birgelen (Member # 6801) on 05-12-2019, 03:35 PM:

Dolby Cinema, every given time:

- Highest contrast available in the industry right now.
- No stupid RGB speckle.
- Far more sophisticated sound system.

Posted by David Ferguson (Member # 10588) on 05-12-2019, 03:50 PM:

Regarding "proper" DMR used on movies shot on 35mm, has anyone here done a comparison on how the 35mm and the 15/70mm look (aside from it being bigger, of course!)? I assume there is some visible difference (otherwise why would they do it) but never having seen 15/70mm I wouldn't know what exactly it is.

Posted by Bobby Henderson (Member # 840) on 05-12-2019, 07:29 PM:

I've seen a couple or so 15/70mm DMR movies that I was able to compare with the 35mm version. One was The Matrix: Reloaded. The DMR process didn't add any more detail to the image than one could see in the 35mm version. All it did was make the blow-up to 70mm less fuzzy than it would have been with a straight optical enlargement from 4/35mm to 15/70mm. In the case of The Matrix: Reloaded the entire movie was letter-boxed in 'scope ratio. They didn't zoom into the image to fill the height of the IMAX screen (thank God). One odd thing I noticed with the IMAX image was a bit of "crush" in the shadow detail areas. It reminded me of how the high pass filter in Photoshop works.

I think the whole IMAX DMR effort was inspired in the 1990's, specifically with the boom of stadium seated theater construction that took off in a big way in 1995. Many of the all stadium seated "megaplex" theaters that opened in big cities from 1995-2000 were boasting one or more auditoriums equipped with really huge screens. Some were as big as 80' across. But they were all 35mm-only. 35mm on these big screens was just dim as hell. None of these new theaters were equipped for classic 5-perf 70mm film projection. 5/70mm prints would have solved the problem since it can throw a far brighter image with better contrast onto big screens than 35mm. But the classic 70mm film format was on its way out. The movie distributors loved the dollar savings 35mm with digital sound offered over 70mm film prints. DTS was available for 5/70mm. But that made little difference to the distributors.

Anyway, IMAX saw all these half-ass giant screen 35mm-only theaters as an opportunity. They could push the IMAX brand into the commercial multiplex theater space and charge a premium for the experience (which wasn't fundamentally any better than watching a 5/70mm blow up print on a big screen). Back in the 1980's and early 1990's it didn't cost anything extra to watch a movie in 70mm versus 35mm. So many people were dazzled by the "digital" buzz word. Eventually IMAX released its own digital projection system and began killing off its own 70mm format.

I think the worst IMAX DMR show (in terms of visual quality) I watched was Superman Returns. That movie was shot with an early Panavision d-cinema camera which, IIRC, had only 1080p HD resolution. The image was taller than other 'scope IMAX movies I had seen. The picture quality was not sharp and the image framing was terrible. I was in the normal "sweet spot" of the theater near the center of the auditorium, but I felt like was seated in the front row with the image way too close to my face. A 35mm version I saw here in Lawton on a normal sized screen looked far more watchable.

Posted by Daniel Schulz (Member # 1881) on 05-12-2019, 07:44 PM:

quote: Haris Ellahi
Thanks a lot for the detailed replies!

Would you guys recommend watching Godzilla: King of the Monsters in IMAX with Laser (and the 12-Track sound system) or Dolby Cinema? I have both available to me.

Like Marcel I lean toward the Dolby Cinema for the HDR imaging and Atmos mix. You can't go wrong ether way, though, the IMAX with Laser presentations are stunning in their own right.

Posted by Marcel Birgelen (Member # 6801) on 05-13-2019, 02:04 AM:

Back when The Matrix: Reloaded was released in 70mm IMAX, I had to see it in that format.

I was properly disappointing with the result. I'd already seen it on a properly scope-sized giant screen in 35mm.

The problem is, since it's entirely framed as a scope movie, you don't really gain any extra active screen surface. The geometry of those classic 70mm houses is also simply not optimized for such a presentation.

While I was pretty impressed by what Disney had done with Fantasia 2000 on IMAX, I wasn't impressed with what IMAX themselves had done with The Matrix: Reloaded. Whatever DMR must have added, it wasn't really visible to me as an added benefit compared to an ordinary blowup. The image didn't seem to have more detail than the 35mm release.

I guess with the original DMR, IMAX slowly got itself into the snake-oil business, by selling some magical black-box solutions to the general public, that effectively didn't do any magic at all.

Posted by Sean McKinnon (Member # 612) on 05-13-2019, 12:59 PM:

quote: Marcel Birgelen
Dolby Cinema, every given time:

- Highest contrast available in the industry right now.
- No stupid RGB speckle.
- Far more sophisticated sound system.

Then why are screen shakers installed on Vision screens if there is no "speckle"?

Posted by Marcel Birgelen (Member # 6801) on 05-13-2019, 01:49 PM:

I guess you could come up with that yourself?

They are there, to avoid you seeing the speckle...

Posted by Sean McKinnon (Member # 612) on 05-14-2019, 10:47 AM:

I know what screen shakers are for. My point is that you said there is "No stupid RGB speckle" when using Vision and that is not true there is speckle and it has to be mitigated with screen shakers.

Posted by Marcel Birgelen (Member # 6801) on 05-14-2019, 01:39 PM:

I guess you know what the point is, but to be sure...

The point is:
- IMAX with lasers: lot's of speckle visible on screen on all the installs I've seen.
- Dolby Cinema: practically zero speckle visible on screen. Seemingly, those screen shakers do their job here.