Streaming the Supernatural

Filmakademie students find an infrared ‘Key’

Perhaps nobody knows better than student filmmakers that ‘necessity is the mother of invention.’ For a group at Germany’s Filmakademie Baden-W’rttemberg, the challenges of making a student film with unique visual effects led, quite directly, to the development of a camera technology they call Thermakey. By pairing an HD camera with an infrared camera, the students were able to capture both visible and thermal data to generate the effects for a diploma film called Lys.

But they didn’t stop there. Convinced that Thermakey could someday supplant conventional green-screen and blue-screen techniques, they have introduced their technology to professionals around the world at conferences like SIGGRAPH Asia, FMX in Stuttgart and Canada’s New Brunswick Innovation Forum. The quartet of Hannes Appell, Ralf Noack, Nicolas Palme and Sebastian Schmidt are hoping that their prototype Thermakey technology will ultimately become a product in the modern toolkit of visual effects.

Not that they could have anticipated this when they began working on Lys a couple of years ago. Fellow Filmakademie student Krystof Zlatnik had come up with a script for a sci-fi short about a girl with the ability to ‘see: and control the energy of other beings. ‘The world was supposed to look different when Lys controlled the energy streams of people and animals,’ explains Palme, the film’s vfx producer. ‘Being students, we didn’t have the manpower, the time or the money to make this with a high production value. So we started looking for a cheap but good-looking alternative.’

‘It was pretty clear that we needed some kind of ‘wunder’ device to realize the flow of living energy inside humans and the biosphere,’ recalls Appell, who was the vfx supervisor on Lys, and now works in visual development at the Frankfurt game company Crytek. Along with Lys director of photography Ralf Noack, Appell investigated the idea of using infrared cameras to create the look of Lys’ ‘other’ world.

‘It was clear to us that those supernatural streams should look very organic and floating’whereas the ‘real’ world should be presented with a rough and edgy handheld camera style,’ explains Noack. ‘But to shoot 80 percent handheld and have nearly every third shot be a vfx shot, the post-production would be far too elaborate to do in the classic way. I started to consider every option and during my research I tripped over some thermal material. What if we could layer a thermal image and a real image to have a further ‘hidden energy picture’ of everything that produces heat? If this could work, we could use as much hand camerawork as we wanted to, and at the same time have very low post-production efforts.’

Noack constructed a rudimentary camera rig that paired a camera with a thermal image camera’not unlike to the rigs used for stereoscopic shooting. ‘When Hannes and I synchronized both image signals, the results looked great. With the help of the camera department of the Filmakademie, I developed a second version of the rig, with a special frame leader which guaranteed the match of both camera images. So we could work with the rig nearly like a normal camera.’

In the process of developing this technology for Lys, the students made an interesting discovery, reports Sebastian Schmidt, the film’s technical director. ‘We found thermal information could not only be used to help us create the look we wanted, but we could also use this temperature information for separating actors from the background.’ Schmidt, who now works as an R&D technical director at London’s Framestore, developed a way to convert temperature data into a usable format for compositing the vfx images in the project.

‘With this software, we could choose different temperature ranges and create perfect keys and masks for the actors,’ notes Palme. ‘The human body’even hair ‘always has different temperatures than the background. We realized that we had found a way, by accident, to simplify rotoscoping. We could use the infrared camera not only for the look of the ‘other’ world in Lys, but we could easily ‘jump’ between the normal picture and the infrared image. We could achieve with an infrared camera the same effect that a green-screen does, simply by using the heat emitted from human bodies.’

The students’ ingenuity earned their fledgling Thermakey technology the Karl Steinbuch Scholarship from the MFG Stiftung foundation, which covered their initial costs. But Palme, who is still a Filmakademie student, admits, ‘Our university doesn’t really have budgets for research and development like at a medical or physics university.’ So the four Thermakey partners are on the hunt for funding that will support further development. ‘Our long-term objective is to integrate infrared and HD cameras,’ says Palme. ‘So actors can be shot in real environments in a way that’s completely light-independent. You won’t have to build green-screens anymore.’

To see Lys, visit www.lys-film.de.