DI from day one: London's Midnight Transfer discusses its DI philosophy

Post, Oct, 2005 by James Nuttall

LONDON -- At first, digital film post just meant scanning the shots that needed treating. Then it became practical to scan all the selected takes to grade and conform digitally. Now London studio Midnight Transfer (www.midnighttransfer.co.uk) has taken digital intermediate to its logical conclusion.

"We came to the business of digital intermediate [DI] from a different angle than most other facilities, so I think we had a clearer approach," says Greg Barrett, Midnight Transfer's head of production.

Midnight Transfer started as a dailies house for feature films, moving from there into offline editing. That meant it came from the movie workflow, rather than commercials and effects, which is how the majority of post houses got into DI work.

"The traditional approach has been to transfer telecine dailies to tape, for viewing and for the offline," explains Barrett. "Because they were being used to evaluate shots as well as to build the cut, the DP worked with the colorist to establish some sort of look for the dailies, to get a good feel for the way the project is going to end up. But that initial grade was then thrown away and the colorist had to start again when it came to the online.

THE PHILOSOPHY

"Our approach--which we call DI from day one--is to start out with a high resolution scan and derive viewing and offline copies from that," he continues. "This gives us the great benefit that the grading decisions made for the dailies are retained and can form the basis of the final grade. The whole thing is a cumulative process."

While visiting Midnight Transfer, the main color suite was checking a conform of British movie Kidulthood with the offline, so a split screen was showing the final grade on one side and the offline from Apple Final Cut Pro on the other. Although the final grade was obviously more refined, it was clear that the original dailies transfer had gone a long way to creating the mood of the movie.

"You are completing your grade with the same colorists on the same machines, using the same files and in the same suite," explains Barrett, adding that you save the production time and money.

THE TOOLS

The first challenge was to maintain productivity in the scanning. Dailies are called that because they are expected to be delivered each day. Traditional film resolution scanners, though, run at significantly less than realtime--measured in seconds per frame rather than frames per second--meaning that dailies could not be delivered the following day, and the backlog was likely to grow ever longer.

With the launch of the Spirit 4K film scanner and DataCine, delivered earlier this year, Grass Valley has unblocked this part of the problem. In 2K mode--which remains the pragmatic choice for virtually all DI work worldwide--it can scan in realtime, provided the network is there to accept it.

The Midnight Transfer architecture is that the Spirit 4K and DataCine is connected, not to a conventional large hardware color processor, but to a Grass Valley Linux-based post production software tool called Bones. Driven from a graphical control panel, the Bones open post framework provides the interface between the GSN output of the Spirit 4K and the dual Fibre Channel network on which the company's SAN sits.

The Bones open framework provides realtime primary color correction, and Midnight Transfer will shortly install the six-vector secondary color correction option to provide comprehensive grading functionality. Not that the primary color corrector is limited: Midnight Transfer recently completed an HD trailer from movie material solely on Spirit 4K and Bones without ever going into one of the full color suites.

As well as realtime 2K scanning, the Grass Valley Spirit 4K can scan at 4K resolution when required, at about 6fps. In addition, Midnight Transfer has installed a Northlight scanner from Filmlight. A Truelight color management system for calibration throughout the facility is also used to ensure an accurate match between Spirit and Northlight scans, so the two sources can be freely intercut.

There are two grading rooms attached to the DI network, each using the Baselight nonlinear grading system from Filmlight. The smaller has a Baselight 4 with a 32-inch Sony CRT monitor, the larger is in theatre style, with a Baselight 8 and a Barco 2K projector.

EASILY SCALABLE

Barrett raises an important point about the architecture and its scalability. "In the classical DI facility, to add another grading room means installing a new system, or an investment of a million dollars plus. With our system we can add another room just with another Baselight and a monitor for a fraction of the price. That makes us much more competitive and flexible as the work grows.

"What makes that possible is the Spirit 4K, which allows us to scan in realtime, and even grade as we scan, without compromising the quality for the digital intermediate. The result is that we can give the director and DP better dailies, and it makes their life easier and faster when it comes to the final grade."