In this world of influencers, there’s something reassuring about the idea that so much R&D is being done to draw people toward cinema exhibition – and in HDR at that.

It’s almost impossible to stroll, exactly, into the recently-constructed West hall of the Las Vegas Convention Centre, which is so continentally vast that visitors are best advised to bring a map, a compass, and three days’ supplies. Still, determined long-distance hikers braving the journey will probably notice Blackmagic Design’s enormous hoardings on the hotel opposite, advertising its new camera technology with many instances of large numbers suffixed with the letter K.

Blackmagic has done shockingly well as a camera manufacturer in its comparatively short history in the business, but this is not about Blackmagic. In fact, it seems reasonable to propose that NAB 2025 is a good example of a film and TV industry trade show which is taking place post a sort of pixel-peeping watershed, at least in the minds of many visitors. Whether the show itself or the exhibitors are universally dedicated to that reality, however, is another matter.

Consider the SMPTE, an organisation which has been pixel peeping at the professional level since before most video was even made of pixels. SMPTE seminars at NAB 2025 have so far seen some really interesting technology applied to HDR cinema projection, presented by Anders Ballestad from Barco. The presentation called it – perhaps rather enigmatically – light steering.

Photons screeching around bends

Amusing as it is to picture photons screeching around bends in the form of tiny racing cars, the new idea actually takes the form of an otherwise unremarkable Barco LS4K laser projector. Under the hood, however, are some new ideas representing some interesting and fundamental optical physics. The intent is that light which would usually be reflected from a micromirror device and straight out the projector’s lens – or not, depending on the brightness of a pixel – can be aimed in a slightly different direction, making more photons available for bright highlights while keeping them away from things we’d like to be dark shadows.

The technique used to do this takes advantage of the (sometimes) wave-like nature of light. On a small enough scale, if we emit two beams of any kind of electromagnetic radiation, including light, from adjacent points with very slightly different timing, reality behaves as if the overall beam of light were bent slightly in the direction of the last-emitted edge. This is how phased-array radars work, although the technique can be shown with sound waves or light too.

This is quantum physics and not entirely intuitive, but this animation makes it fairly clear how things behave in practice; notice that each emitter emits energy which radiates into a spherical area, but the combined wave fronts are at an angle. 

Low power consumption

The physical hardware used in the projector includes a phase modulator – a device which can sub-microscopically adjust the position of elements to change the phase relationship (that is, wave synchronisation) of the light waves). The resulting projector is no larger or more complex to use than a conventional Barco laser-driven digital cinema device and, perhaps crucially in 2025, it does not consume any more power than other, more conventional designs. 

The results look good: the design targets 300-nit HDR images, improving both the brightest peaks and darkest shadows, yet without requiring any more actual light power from the projector. Yes, there are limits in that we can’t drive the entire display to absolute peak brightness at once, which recalls the bad old days of ANSI contrast measurements on three-tube CRT projectors which lacked the power supply capability to drive the entire tube at peak level.

The counterargument is that we often don’t want to drive the entire screen to high brightness, which would be painful, and that’s certainly true. What’s crucial here is that this approach to HDR doesn’t require a projector to be able to achieve full brightness across the entire screen, and then block out most of that light, most of the time, as would otherwise be the case.

New tools required

HDR has been tried before, by experienced companies, for both home and cinema exhibition, and it is still some way from universal adoption. Either way, this new idea is possibly the most reasonable way to get HDR into cinema. Particularly, it’s considerably less expensive and power-hungry than LED video walls, which have been suggested for this sort of application (in the form of Samsung’s Onyx system). At the same time, light steering demands another specialist deliverable which distributors must create. Colour processing specialists Colorfront have produced tools to allow colorists to accurately preview the 300-nit image, observing its limitations in terms of total absolute brightness, and trim accordingly.

Among all of the things which have recently been proposed as a way to improve cinema, with its century-old imaging standards, HDR probably meets with the most universal approbation. Like most kinds of HDR, this new 300-nit concept for cinema makes standard dynamic range look broken by comparison, and it’d be nice to think that cinema in general could exceed the miserable 48 nit brightness which has long been standard. It isn’t clear that this is the way that will happen, but it’s a pretty credible option with some interesting tech, in the phase modulation, that hasn’t been around cinema much before.