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  • Writer's pictureChris Rogers

Screen saver 2: Lights, camera, action!

Updated: Nov 24, 2022

The BFI IMAX screen reopens to the public today following a few weeks of closure for re-equipping and refurbishment, this in turn coming after the institution regained control of the venue in the summer. There’s a new screen, better seats and extra speakers, but the key change is – finally – a state-of-the-art ‘IMAX with Laser’ digital projector. Sadly it is not capable of filling the full height of what is still Britain’s tallest, largest screen (more on that below) but will be bringing qualitative improvements over the existing photo-chemical kit. On Tuesday I and a handful of others had a sneak preview of the results, along with a behind-scenes-tour.

The screen is the third to be fitted since the cinema opened in 1999. It was brought into the building in one piece and installed by riggers, before being painted with its reflective coating in situ using a robot running on a rail and track system. Perforated to allow the speakers behind to function, additional speakers now give 12-channel/6.0 sound. Seating capacity has been maintained, for obvious reasons, but we tested the plusher replacements by watching a short showreel. Comprising clips, trailers and a summary of the technical improvements (higher contrast, brighter image, wider colour range), it certainly set the scene for future releases.

In the projection booth (actually a room), we saw the new projector. It weighs three quarters of a tonne and just fitted in the freight lift (“I had a one-tonne stair climber on standby,” said Head of Technical Services Dominic Simmons, “though we weren’t looking forward to taking it up five flights”). A chiller provides the necessary cooling when the projector is in operation.

The current state-of-the-art in digital IMAX is a dual laser projector that can illuminate large screens for the full height of the tall 1.43:1 ratio. This was considered for the refit at Waterloo but not, in the end, taken up. Explaining this to me some time after the tour, Dom said: “The decision to install the single laser opposed to the dual laser projector was not taken lightly, but a result of prioritising the premium position and operability for the 15/70mm GT film projector. At the BFI IMAX, being able to screen a wide range of screen culture is central to our vision so it was crucial to maintain our capability of 15/70mm, high quality laser and 35mm projection. The physical space could only accommodate a dual laser projector at the detriment of the quality of screening in other formats.” There are very limited films available that take full advantage of the dual laser system, he added, but noted that “Our COLA laser also has higher specifications for 3D playback as it can project high frame rate 60Hz 3D in 4K; dual laser can only do this in 2K.”

Installation was verified by IMAX staff, who check all IMAX projectors every six months. The new machine’s performance is also calibrated and monitored remotely through inbuilt cameras and even microphones. As it’s digital the actual content is usually downloaded, though on our visit Black Panther: Wakanda Forever was half way through being ‘ingested’ into the projector from a small silver hard drive in preparation for screenings.

Impressive though this was, what I really wanted to see stood alongside – the BFI’s original 15/70 IMAX film projector. Even bigger than the digital version and even heavier, and that’s before considering the separate ‘cake stand’ platters that hold the film reels, it is one of sixty left in operation worldwide – the only other in London is in the Science Museum. Master projectionist Michael Ford kindly allowed us to look “under the hood” – literally, since that is what the raisable shield concerned is called – to examine the heart of the machine.

Conventional motion picture projectors use ‘claws’ that engage with the perforations in the film stock, pull it down to the lens and hold it there momentarily but this proved too destructive when running at the speed needed for IMAX. The solution, patented by an Australian and discovered by IMAX’s Canadian inventors, was the rolling loop. Film is fed into the projector body and around a large ring or rotor; gaps at fixed intervals generate a loop of film that grows as it approaches the aperture, is held there briefly by a vacuum whilst the frame is illuminated and shrinks away afterward. This motion occurs twenty-four times a second and is gentle enough to prevent damage, the perforations now serving only to correctly position the frame rather than transport it.

The BFI’s 15/70 projector has two rotors, mounted one above the other, for showing 3D films – each is fed by a different platter as the right and left eye images are subtly different. There are of course two lenses as well, and two 15,000-watt xenon lamps costing about £10,000 for the pair. These create so much heat that the lamphouse above the rotors must be water-cooled – this is achieved by another chiller located outside the projection room, and occasionally “you get drips”. Michael explained that supervision is still necessary throughout a 15/70 screening to remove dust and watch for other problems. “Each run is like the first,” he said, noting that you also learn how the projector is running from the sound of it. Mechanically driven, liquid-cooled and fed with compressed air, the 15/70 is the Rolls-Royce of the IMAX stable (making the laser variant, perhaps, the Tesla) and would be immediately recognisable as a film projector to Georges Méliès or the Lumière brothers.

Both Michael and Dom were clear that this is what large-format cinema is all about, and I was delighted with my “souvenir” from Michael – a strip of film cut from an IMAX-format movie. From it I could see from it how regular widescreen imagery is printed onto IMAX film stock alongside actual IMAX footage. This is how feature films made using both formats, such as Christopher Nolan’s Dunkirk or Tenet, are screened at an IMAX venue using a single projector and indeed a single reel. Michael said that experiments with stronger platters to carry longer films are under way, rumoured to be for an upcoming director’s new production. We were told that Christopher Nolan sometimes uses the BFI IMAX to screen rushes, which might explain why there was a storage rack nearby holding all of his recent films on IMAX platters. This rather put one’s own home video collection in the shade, although at least I don’t need a pallet truck to put a DVD on…

The control position for both IMAX machines, two conventional digital projectors and the trusty conventional film projector sitting quietly at the back of the room looked like it came out of a nuclear submarine; what Michael and team will be commanding from there engages the question of programming.

We were told that the BFI plans a range of “complementary” screenings at the IMAX to tie in with the main riverside venue, as demonstrated by the recent Bowie season there alongside showings of Moonage Daydream at the IMAX. Using the latter to bring “additionality” and “context” was also proposed, to help explore film in depth. Intrigued but also keen to test those ideas I outlined in my summer post, I connected with Stuart Brown, Head of Programme and Acquisitions at the BFI, after this week’s event, who very kindly provided some answers early this morning:

Can you provide an overview of future programming at the IMAX?

The vision for the programme at BFI IMAX going forward is very much to retain the core programme of large scale, blockbuster releases that BFI IMAX audiences know and love; but to enrich that offer with a more adventurous and diverse programme that will see a wider offer of contemporary cinema - as already demonstrated by Moonage Daydream and Fire of Love, special one offs (see Indochine in the forthcoming programme as an example), timeless classics that lend themselves to large scale exhibition – i.e. Akira, Seven Samurai, 2001: A Space Odyssey, Blade Runner etc, and archive programmes.

We intend to draw the BFI IMAX close to BFI Southbank and will be cross programming. We have started this already with the Bond weekender and the Ryan Coogler focus. In the long term we hope that audiences will see the BFI IMAX and BFI Southbank as one programme with the screens in both venues embracing a wider and richer definition of moving image culture.

Does the BFI see potential in showing some of the original 40 min 15/70 documentaries, and other productions that have acted as a bridge between those and the current part-IMAX features like Christopher Nolan makes?

Yes we are currently auditing the holdings of these films we have stored at BFI IMAX and have opened conversations with various distributors. The plan is to start screening 40min films in January. Both historically popular titles and new additions to our programme, which we’ll present as part of our education programme offer on weekday mornings but also alongside feature films across the whole public programme.

And your thoughts for reformatting e.g. Victorian large format films from the archive?

The success of the Jaws and ET screenings over the summer – which were remastered for IMAX – show there is real appetite for audiences to experience films in this venue, beyond the new release blockbusters we are rightly famous for. Alongside features that utilise archive footage such as Moonage Daydream and Fire Of Love. We do so much at the BFI – from archive to immersive – and there is huge potential with this venue. Of course any roll out of our vision will be incremental, we can’t do everything at once, but we will certainly be working closely with our colleagues at BFI National Archive to present more evenings of special archive presentations along the lines of the Victorian large format films and South. Watch this space for some exciting announcements on upcoming projects in due course.

Finally is there the chance, given the lovely projection suite we saw last night, for workshops and demo days of a range of wide- and large-screen showings, noting Michael Ford's BKTS posters on the wall!

This is certainly part of our thinking going forward. We love showing people our very special projection box and technical capabilities.

This is a cheering and promising response, clearly. The return of those original documentaries is key, I think, re-exposing (as it were) audiences to the reason that ‘Rolls-Royce’ exists, and it was certainly good to hear on the tour how highly-regarded the 15/70 format generally is. Balancing the commercial, historical and technical attractions that might be realisable across the available spectrum of film formats will be a challenge, but it will be good to see how the BFI takes these thoughts forward. Lights down.

With thanks to Grace Yeoman, Claire Morris, Colette Geraghty, Dom Simmons, Mark Mannix and Michael Ford at BFI and Premier and of course to Stuart Brown. Black Panther: Wakanda Forever opens at the BFI IMAX today.

[This piece was edited 24 November to clarify the dual laser issue]

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Chris Rogers  |  Writer on architecture and visual culture

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