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IMAX Laser - The Future of Cinema

IMAX take theatrical presentation to the next level

by Steve Withers Oct 21, 2015


  • Since the dawn of cinema, projection has used a lamp or bulb of some form or another. That approach, whilst effective, has always had certain limitations but all that is about to change.
    Over the last few years we have seen a gradual move towards alternative light sources being employed and in the commercial cinemas the latest technology revolves around lasers. So it was with some excitement that we attended a special demonstration of IMAX's new Laser cinema at The Empire in London's Leicester Square. The Empire will be familiar to any film fan and it seemed appropriate that the famous cinema should play host to the next generation of theatrical presentation. As Justin Robbins, CEO of Empire Cinemas, said at the start of the screening "laser is the future of cinema, delivering the story to the screen in the best possible way."

    Operating since 2005, Empire Cinemas takes its name from The Empire Leicester Square, which first opened its doors as a theatre in 1884. From the earliest days of the moving image, this flagship location in central London has been at the forefront of advances in cinema technology. It was at this very theatre in March 1896, that Louis and Auguste Lumière presented the first theatrical performances of a projected film to a paying U.K. audience. The Empire is now taking the next step in the advancement of cinema technology with the opening of the first IMAX Laser cinema outside of North America.
    The Empire hosted the Lumière brothers first theatrical performances of a projected film to a paying U.K. audience in 1896.
    IMAX itself has been operating for over 45 years but the creation of a laser projector that could meet their exacting standards was the biggest research and development project in the company's history. It involved hundreds of engineers across three continents, taking five years to complete and costing over $60 million. IMAX also bought over 120 different patents in laser optics from Kodak as part of the development process. The reason that the development took so long was because IMAX felt that the existing laser projectors just weren't capable of delivering the kind of brightness and contrast performance that they needed for their huge screens.

    Current laser projectors from manufacturers like Christie or Barco use three DLP chips mounted into a frame provided by Texas Instruments. This is combined with a prism and a laser light source instead of a xenon bulb to create the red, green and blue primaries that make up the image. However this frame was originally designed for use with xenon bulbs, so the laser heats up one side of the frame causing convergence issues which result in light bouncing around and ruining the black levels. IMAX have developed their own frame to hold the individually housed DLP chips. This frame uses a more thermally stable material that eliminates any convergence issues caused by heat and thus retains the black levels and contrast performance.

    IMAX pointed out that their current xenon bulb projector has a sequential contrast ratio of 2,600:1 and that current laser projectors from Christie and Barco have a sequential contrast ratio of 2,000:1 in 2D and 1,800:1 in 3D. Whilst IMAX wouldn't actually say what the sequential or intra-frame contrast ratios of their new laser projector actually were, they did say that it was capable of a dynamic range that was "multiple times better than film". The laser projector also meets the current DCI/P3 colour space but, with one eye on the future, it's also able to support the incredibly wide Rec.2020 colour space and High Dynamic Range (HDR). The new IMAX laser projector can also handle frame rates from 24p up to 60p, which might come in handy if James Cameron get's his way with the new Avatar sequels he's currently developing.However since the IMAX laser projector system will only be used in cinemas with a screen size of 75 feet or larger in width, it isn't just about improved blacks and contrast ratio, they also need to be bright - very bright.

    IMAX are actually employing a dual-projector system with two 4K laser projectors diagonally offset and aligned together. This means that IMAX can not only project 4K material but also deliver productions shot in IMAX's own 70mm film stock (which is equivalent to 8K) at a higher resolution. The combination of two projectors also means that IMAX can fill their huge screens with 22 foot-lamberts (fL) of brightness and to put that into perspective the DCI specifications for 2D cinema projection call for 14 fL of brightness. IMAX also pointed out that the improved sharpness, brightness and contrast performance of their laser projectors gives them greater latitude when it comes to the brightness of 3D projection. In fact with one laser projector each for the left and right eye perspectives, IMAX Laser can deliver a brightness that is almost equivalent to 2D projection. To once again to put that into perspective, the DCI specifications for theatrical 3D projection is a paltry 4 fL!
    IMAX Laser exceeds current DCI specifications with greater resolution, increased brightness, superior contrast ratios and even a wider colour space.
    The launch of IMAX Laser isn't just restricted to the development of the projectors themselves, it also extends to the design of the actual cinema. IMAX we very keen to stress that there is little point in developing a projector with superior black levels and contrast ratios if you then ruin that performance with reflected light onto the screen. IMAX said that when it comes to their new laser cinemas they only use three colours in the interior design - black, black and black. So once the lights are out, aside from the mandatory exits and emergency stair lighting, the cinema is completely dark. That's a lesson that anyone planning their own home cinema should take to heart, especially if their projector has good native blacks and a decent contrast ratio.

    The huge 87 foot wide screen itself is four stories high and uses a standard 1.43:1 IMAX aspect ratio with steeply tiered seating and premium leather seats. The only negative was the general lack of leg room which was undoubtedly a result of having to fit the new cinema into an existing space. A couple of years ago The Empire split its huge main screen into two smaller venues, one of which has now been converted into the IMAX Laser cinema. IMAX said that they have also developed new technologies to prevent the 'sparkle effect' that sometimes plagues laser projection and the screen material itself has been specially designed to reduce hot spots. To ensure that the image is always perfect there is a camera mounted in the cinema that recalibrates the image for alignment, focus, brightness and colour accuracy every day.
    However, as George Lucas famously said, the image is only half the experience and IMAX Laser also boasts a new sound system with 12 discrete channels and sub-bass. This adds extra channels to the sides, rear and above to create a more immersive audio experience. IMAX has traditionally used a 5.1 sound mix with deeper bass that is an octave lower than the competition but this new system will instead use 12 discrete channels. IMAX feel that this is a better solution than using object-based formats like Dolby Atmos because all their cinemas will be built to the same specifications. This means they can deliver exactly the same audio experience every time, whilst Dolby Atmos has to map the original object-based mix on-the-fly to meet the dimensions and speaker configuration of each cinema. As with the image, the audio can be regularly fine-tuned for frequency response and volume using special microphones built into the cinema.

    The first films to include this new sound mix were the IMAX screenings of Ant-Man and Everest but IMAX feel that the use of overhead speakers will become more common as filmmakers gain more experience in using them in creative ways. Each IMAX laser cinema is also linked to IMAX’s 24/7/365 Network Operations Center, which is constantly monitoring thousands of system components to ensure optimum performance at all times. Although there is obviously a cost attached to building these new laser cinemas and IMAX has to create two different DMR (Digital Re-Mastering) masters - one for xenon and one for laser - there is a longer term advantage aside from the obvious gains in performance. Laser projectors are a lot more economical to run because they don't use the huge 15kW xenon bulbs that require a water-cooling system.
    IMAX Laser doesn't just mean a better image, the recently developed 12.1-channel sound system can deliver a whole new level of immersive audio.
    IMAX are certainly proud of their new laser cinemas and Andrew Cripps, President of IMAX EMEA, said: “We are raising the benchmark once again with the launch of IMAX with laser at Empire Leicester Square - providing film fans in the West End a cinemagoing experience unlike anything they’ve ever seen or heard before. We couldn’t be more excited to mark the European debut of this new laser technology at such an iconic venue - particularly with the strong upcoming slate of films, like SPECTRE and Star Wars: The Force Awakens, that demand to be seen in this new format.” However it wasn't just a question of IMAX claiming their new laser cinemas were superior, they were prepared to back up these claims with a detailed demonstration - which is why we were there.

    Taking us through this special demonstration was Brian Bonnick who is Chief Technical Officer at IMAX. It was Brian who originally championed the development of IMAX DMR (Digital Re-Mastering) technology, a proprietary system that was designed to digitally re-master Hollywood blockbusters into IMAX’s format. He also headed the development of the IMAX MPX theatre system, designed to enable commercial multiplex operators to more easily enter into the IMAX business by retrofitting an existing multiplex auditorium, as well as the company’s transition to digital projection and the creation of its new digital auto calibrating sound system. However most recently, he has spearheaded the development of the new IMAX Laser projection and sound systems.

    Brian started by bringing up a standard ANSI checkerboard pattern - which should be familiar from many AVForums TV reviews - which he used to demonstrate the superior intra-frame contrast ratio performance of the laser projectors. Brian was keen to stress the difference between sequential and intra-frame contrast ratios, again something that might be familiar from our display reviews, and the intra-frame contrast ratio performance was incredibly impressive. The black squares appeared black, without being washed out by the white squares around, and the white squares appeared bright and white. He next showed an IMAX trailer in an aspect ratio of 1.90:1 and the black levels and contrast ratios were the best we had ever seen from any projected image in a cinema.
    Then to really demonstrate the full potential of the twin laser projector system, Brian showed a clip from the IMAX documentary Rocky Mountain Express - which was shot in IMAX 70mm. This film had recently been shown to 300 SMPTE engineers and they were apparently as impressed as we were by the images on show. The level of detail and sharpness was breathtaking, whilst the colours, black and dynamic range were a revelation. The blacks were really black but there was still detail in the shadows, whilst the brass on the locomotives and the highlights in the reflections are incredibly realistic.

    Although the new system uses two native 4K laser projectors, the reality is that the majority of Hollywood films are still currently finished in 2K resolution for theatrical presentation. So Brian next showed the trailer for How to Train your Dragon 2 which was finished in 2K in order to demonstrate how good even that could look thanks to the combination of IMAX DMR and laser projection. Of course one of the big advantages of the new laser projection system is the increased brightness with 3D presentations and to prove this Brian showed the first teaser trailer for Star Wars: The Force Awakens. The initial 2D screening was visceral enough, with the huge bright screen filling your field of view and the 12.1-channel sound thundering with the main Star Wars theme. However the 3D screening was remarkable, it really was just as bright as the 2D presentation, completely immersing you in the experience.

    For further demonstrations of the potential of laser projection, we also saw the trailer for Batman v Superman: Dawn of Justice, which has a deliberately grainy and contrasty look that the IMAX presentation perfectly replicated on that huge screen. IMAX also mentioned that they were working with Disney on the live action version of The Jungle Book and that the IMAX laser version of that film might use a Rec.2020 colour space. After the various demo clips we finally got to the main event, a screening Robert Zemeckis's new film The Walk. Robert Zemeckis has, along with Christopher Nolan, been a big supporter of IMAX for years and The Walk was designed to be a 3D IMAX experience from the very beginning.
    IMAX Laser delivered the best projected images we have experienced, with deep blacks, bright images and a staggering level of detail.
    The Walk tells the story of Philippe Petit's attempt to walk a tightrope strung between the twin towers of the World Trade Centre in 1974. The film itself has its limitations, not least of which is telling a story that was already effectively covered in the documentary Man on Wire, but that isn't really why the film exists. It's the last 20 minutes of The Walk, when you're up on the wire with Petit (played by Joseph Gordon-Levitt), that is its entire raison d'être and when viewed on a huge IMAX screen in laser projected 3D the experience is simply vertigo-inducing. In fact there were audible gasps from some of the audience and the immersive audio experience really added to the sensation of being at the top of the World Trade Centre, which was brilliantly recreated by Zemeckis's effects team.

    Robert Zemeckis has been shooting in 3D since The Polar Express way back in 2004, so he knows how to use the added dimensionality to full effect. IMAX use the same wavelength multiplex visualisation approach to 3D presentation that Dolby 3D uses, with narrow band filters on the projectors and glasses to ensure that each eye only sees the part of the image that they're supposed to. This approach results in more accurate colours when compared to the usual polarised filters but we did notice reflections inside our glasses, possibly caused by the increased brightness. We pointed this out to Brian and he said that IMAX were working on a solution. Otherwise our only observation was that the sheer size of the screen and the increased resolution made it easy to spot that The Walk was finished in 2K, something that we confirmed with Brian after the screening.

    During the demonstration, IMAX premiered the new SPECTRE trailer in 2K but were keen to stress that when the film actually opens on the 26th of October the IMAX presentations will use a 4K DMR master. Funnily enough, as we were leaving director Sam Mendes was going into the cinema to see the final 4K IMAX version of SPECTRE laser projected for the very first time. We have no doubt he would have been equally as impressed.

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