The Force of Dolby Cinema

By C J Flynn | February 29, 2016 3:11 am PST
Dolby Cinema at AMC Prime Announcement

When it comes to quality cinema theaters, we in Los Angeles have the luxury of choice. One example: even though laser projectors are a rarity world-wide, on the opening day of StarWars two different laser systems went online at two different style of high-end facilities. With that, we are finally able to more easily compare different technologies, and we can judge how those technologies reproduce quality when the movies weren’t ‘optimized’ with and for that technology.

Hours before the 8PM Star Wars release time, AMC was able to open a Dolby Cinema | AMC Prime room in Century City. There was no official announcement but opening day tickets sold in minutes.

Christie was also able to issue a press release the day before, announcing a dual-laser system with Dolby 3D at the Cinerama Dome in Hollywood.

Two months ago the AMC 16 in Burbank announced the opening of their new Dolby Cinema | AMC Prime auditorium. Several industry and non-industry journals did well, explaining how the projectors and screen achieve 1,000,000:1 contrast, with more detail in the deeper, smooth blacks and the increase of light level from the normal 48 candela/square meter to 108. The demonstrations were every bit as jaw-dropping as they were when first publicly shown at CinemaCon 6 months earlier. The message of brighter colors and greater depth, matched with the great sound from the Atmos object oriented sound system and superb seating with low-end boost gave more tools for the author and the ultimate presentation to the audience.

The next big movie release was Spectre. It as then that several colorists who attended commercial showings of the movie found out the nuance in the message. Now we know that the client must be aware of whether the movie was mixed and color timed for Dolby Cinema. That is, was there a Dolby Vision million to one pass made for the movie and was there an object oriented mix. It could be both (as Star Wars and Mission Impossible are), or it could be neither, and it could be Atmos only. It is unlikely that it would be Dolby Vision without Atmos, though it is possible.

Why is this significant? First, Dolby’s point is that the AMC Prime, Dolby Cinema combination – even without a movie release made for their technologies – still delivers the ultimate in potential sound and image quality and comfort. They point out that their clients, in this case AMC, chooses to book the theater with the movies available and sometimes they will book movies that aren’t in Atmos and Dolby Vision. Which is a lot to put on a bumper sticker, or an asterisk at the bottom of the entry way sign that announces the Dolby Cinema room.

The three colorists who your author sat with watching and listening to Spectre all felt that something was wrong, but weren’t yet aware about this color timing thing. Everyone noticed artifacts in deep colors, in the deep blacks especially. It was obvious that this wasn’t color timed for a million to one. And as well done as the sound was, it was obvious that it wasn’t object oriented. There was one big scene when the sound music got louder in the front and reached out as far as it could…it should have/could have burst into the room in some clever way but it just stood there like an over inflated balloon, or an effect that could never do anything because the alternative was to enter into the arrays which would have been too much. Alas.

This is when the detective hunt came about. It took multiple emails and interviews to find out the situation.

First, we are told that if a movie isn’t timed for million to one, the dual laser projectors get tamped down to 5000:1. Which is a lot, except that it is more than twice what it was ever seen in most any post production suite. The Dolby response was:

The fixed luminance gamma function defined by DCI supports over 7,500:1 contrast, and the Dolby Vision projection system faithfully map those fixed luminance codes to the proper luminance levels on the projector.  Dolby doesn’t alter what the content is representing.  Many post houses have projection systems in excess of 2,000:1 contrast and they grade under ideal conditions, which allows them to produce content in excess of 2,000:1.  We don’t believe there are any post houses with systems in excess of 5,000:1, and as such limit the darkest code there (i.e. anything over 5,000:1 is soft clipped to 5,000:1).   When post houses can grade on higher contrast systems then we can increase our levels to match. No matter the content format a Dolby Cinema is still the best place to see and hear a movie.

Last sentence first, this makes sense. Most Atmos systems will have new audio equipment which can better handle high levels with low annoyance due to recent calibration and low THD from new equipment and components. Because the rooms have been tweaked a bit, they probably handle early reflections well. And because several individual speakers are delivering the sound, it is likely that the sound level can match the mixer’s level – by leaving the audio processor at ‘7’ – and deliver each of us a cleaner image that is apparently loud without being overbearing.

The problem might come from the choice to clip at 5000:1. It is probably correct that most facilities are grading at around 2000:1. That is the spec for most of the TI projectors. Until the new release of Sony projectors (8500:1) and laser projectors, even 2000:1 is difficult to attain. In practice at the best post houses, a carefully tweaked 4K xenon bulb-based projector system is hard pressed to get to 2000:1 and a little over 2000:1 is the best a 2K will do. So most people seeing the movie at the final post stages are seeing it at 2000:1. Compression artifacts that don’t show at 2000:1 may show up at 5000:1…and this is what is posited.

It is possible that there are 5000:1 monitors in use at the post house, but they are not large screen. These screens, of which the Dolby Professional Reference Monitor PRM-4220 is the premier, are brilliant and have their place, but they could also hide something that looks ugly on the big screen. And thus it goes for the very areas that are, or are supposed to be the glory spots for the system.

So either check the Dolby site before you go to the movies to see if your choice has the Dolby Vision and Atmos, or train your ears and eyes to stop waiting for the added dimensions and subtleties of those systems. As one colorist said, “At least we got comfortable chairs.”

Back to watching Star Wars: The Force Awakens with the purpose of evaluating the laser and object sound system.  So very unfair, as it is simultaneously a pleasure and disconcerting to have to break the wall of disbelief to pay attention to dark areas, to force oneself to notice nuance and smoothness in the dark during dark scenes. It was a pleasure to hear the objects going exactly where mixer Andy Nelson needed them to be, and a surprise to feel how well the low end was tied into the seats, even having directionality. It is still disconcerting at first, even having experienced it a few times, but once or twice done well it becomes an appropriate part of the mix.

So Dolby gets a Well Done for getting another group to implement two out of three of their important technologies without excess or neglect. The third technology – Dolby 3D, is no trifle. Having seen movies that have been timed for 3D at 48 candela, it is a shame that AMC has decided not to show 3D in their Dolby Cinema | AMC Prime rooms. The extra light brings a completely new aspect to a movie. All the cues that the human visual system uses for placing objects in space are enhanced. It is especially wonderful on a low-gain white screen eliminating all the vignetting and false contrast that a high-gain / dark silver screen delivers. And the AMC Prime rooms have that nice screen, in contrast – if you’ll excuse the expression – to the out of spec screens used with the other technologies.

Dolby also gets a demerit for not thinking through the effect of allowing their name to be used in a manner that implies more than it can deliver. Telling their patrons that they must search through pages of PR on their cool but hardly searchable website to find as to whether a movie has the proper imprimaturs is not a good solution. Knowing Dolby for the good faith actors that they are, they will find the right solution.

AMC also gets a Well Done for the excellent job they do physically. A.) Good marks for providing a nicely done room. The long-wavelength red accents throughout the room, especially on the speakers is technically terrific for pre-show eye accommodation, and aesthetically first rate. B) Good marks for the un-ostentatious, nicely protected alcove which, although removing several seats under the port glass, protects the miscreant patron who would be so stupid as to jump on a chair and look into the projector lens. This solution will be common in the world of laser projectors, which have to follow health code regulations based upon a ridiculous mis-application of logic and an anachronistic understanding of how lasers are used in the projector. (They’re treated as if there are coherent laser beams actually coming from the lens.) As if the light exiting the lens isn’t the same beam of divergent (non-laser coherent) photons that exit any projector’s lens, which is to say: A lot.

In addition to all that wonderfulness, AMC still gets the same demerit as Dolby does for the poorly handled ‘hole’ they leave in a patron’s education. There must be some way to educate the audience member that they are purchasing tickets for a movie presentation that isn’t optimized for the equipment that is being highlighted in the room. They also get a demerit for not showing 3D presentations when the system they have would be the best presentation possible: No Silver Screen, No High Gain Screen, No Vignetting and dark patches, glasses that are as matched to the eyes as possible (including children’s glasses, a very important detail) and 48 candela/square meter displaying a movie in the way it is supposed to be seen. Presentations, like all engineering, is the art of balancing compromises. Dolby has gone all out to push with these three components to reduce as many of those compromises as possible. It would be nice to see them all working.

So now we have to go to the ArcLight Cinerama Dome to sample the Dolby 3D, but the PR – which is notoriously poorly written – says that the light levels will be at 27.5 cd/m2, an odd number (well, it is an even 8 when divided by pi when using the deprecated and unwieldy foot/lambert system) considering that it is still 10 cd/m2lower that the lowest limit of exhibition expectations (48 being the CalibratedWhite Luminance, center specification, with a Theatrical Tolerance of ±10.2 cd/m2 – or 14 fL ±3 in the old style). But this isn’t any theater. This is the theater that we saw movies from Mad Mad Mad Mad World to Apocalypse Now, Gone With The Wind to Out of Africa in. This Christie dual laser system should be giving us the max. More when that viewing happens.

Enough of the rant. Just as the new Star Wars: Episode VII – The Force Awakens is the movie that needed to be made to launch us into a new future storyline, the new object oriented sound system(s) and laser projectors are the equipment for the next iteration of digital cinema. In addition to putting more shadows into the dark, and potentially more colors into the spectrum, we should look forward to better Live presentations, whether Event Cinema or Alternative Content. I look forward to a live presentation concert with a mixer in the center seats mixing bed channels and objects special to the auditorium.

Good luck to us all.

C J Flynn