Post-production: The colour of Tomorrow…
For Tomorrow, When the War Began, post-production/VFX vendor The Lab conceived and invented a colour calibration process called the Digital Print System (DPS). Its creator, head of digital intermediate Al Hansen, tells the story behind this innovation.
Tomorrow, When the War Began was the perfect project to utilise this colour calibration process, because it was a big feature film with an experienced cinematographer and production team.
We demonstrated the DPS calibration technique by showing test results to the film’s producers, Michael Boughen and Andrew Mason, and executive producer Christopher Mapp, during pre-production. With the support of the cinematographer, Ben Nott, ACS, we embarked on a method to completely colour-calibrate all levels of the production, ensuring that the images – from rushes to post – maintained the characteristics of the final 35mm film deliverables.
Nott understood the process and saw the advantages of viewing all images to the final film print, as well as delivering savings in time and money on the transfer of rushes. Mason trusted and believed the post workflow could be done and gave us the go-ahead to do it.’
POWER TO THE DOP
Having shot feature films using both 35mm film stocks and the various digital platforms, Nott was acutely aware of the importance, regardless of the choice of the acquisition medium, of planning for the film’s final release whilst still in pre-production.
Whilst 35mm film stock is a superior acquisition medium, rushes colourists can have a subjective influence and in many cases without accurate reference. They may have no option but to apply a personal spin to the images.
The Digital Print system removes this decision-making from the dailies colourist and returns the power of determining the fine trims of light and shade and colour bias to the cinematographer. Ben Nott said the system had made him “a much better cinematographer”, with a better understanding of the colour negative and more discipline about exposing it.
“The result is an offline edit of the project that is even in exposure from cut to cut, and although compressed, the images approximate the colour and contrast values of the final product. This is important not only to the editor and director, who deal with the film in this mode for months before the DI, but also screenings for studio execs and distributors require very little tweaking to look fabulous,” he said. “The images in dailies were only ever viewed as they would be interpreted by a film print. Consequently, I regarded exposures and colour reproduction only within the latitude of the print stocks.”
Grading rushes is something that has always taken place, long before the non-linear era hit. Back when all the rushes were printed, it naturally had “a film look” and most experienced cinematographers just wanted a one-light grade that was set up prior and rolled out through the whole shoot. This put “the film look” of the film directly in the hands of the cinematographer.
HOW IT WORKS
Since the advent of non-linear editing, productions deliver video rushes instead of 35mm print rushes. Video is more economical in both cost and time; it has become the norm for feature film rushes to be transferred to tape or Avid via telecine, which are un-calibrated devices. This means the director, cinematographer and editor were not looking at accurate images of what was really shot.
I developed a system in conjunction with colourist Peter Simpson, which has been used by film and television productions since the 90s, called Video Aim Density (VAD). It calibrates the telecine to the camera and film. However, this process and the Digital Print System had never been used together – until now.
The Digital Print System goes one step further by calibrating the telecine to the Northlight 2 Scanner and is viewed under a print emulation Look Up Table (LUT) as log-in video. Effectively, the DPS on Tomorrow When the War Began emulated on the cinematographer’s camera equipment, lenses, on-set monitor and rushes what the film was going to look like on 35mm print.
The entire process was treated like a digital intermediate where everyone was using the same LUT and working within the same parameters as the colourist and cinematographer, because all variables across the production had to be eliminated to ensure an accurate workflow.
As film is still the main deliverable, it was imperative to work with the actual 3D LUT that would be used in the final post. It would consist of the exact process the final images would go through, as well as possessing the actual characteristics of film. We approached Tony Poriazis, head of digital imaging at our sister company, Digital Pictures, to build the LUT and assist us in the film-out process. As they would be doing the final record out to film, we brought Poriazis on board at the beginning and worked backwards.’
Before shooting commenced, we completed a calibration loop of the entire process, and determined the format from a series of camera tests to decide which stocks to use.
Implementing the DPS system was an enormous undertaking, because in addition, The Lab was providing rushes, scanning, 230 VFX shots and digital intermediate grade, as well as hosting the editorial team in-house using three Avid suites purpose built for the production.
It was all worth it because Tomorrow… is, without a doubt, one of the most even and colour accurate films I have ever seen come direct from camera in my 30-year career.
