Calibration Is Key For a New, True-Color Dailies Telecine Process

LaserPacific says it's devised a solution to leap one of the last major hurdles in the digital post process – keeping color consistent across the board, from the D.P.'s on-set color-correction station through dailies, into preview screenings, and inside the DI suite.
Anyone who's tried to wrangle digital post knows that color is that last 10 percent of the process that takes 90 percent of the time to get right. It's not hard these days to put together a pipeline that encompasses digital dailies, preview screenings, and DI work. But the trick is making sure the image actually represents the work at every step of the process – that as the color space is transformed, the D.P, dailies colorist, and studio executives all see the color as the cinematographer intended it, rather than as it happens to look on any given display. The LaserPacific "accurateIMAGE" system, known as aIM for short, is designed to make digital images look like film all the way through the post workflow.

So how does it work? Most importantly, LaserPacific has to be the vendor for everything from dailies through the DI, ensuring that the various displays are all calibrated. First, LaserPacific sets up a process for the D.P. to specify color decisions on set. Working with a print-film LUT and a HD projector, the dailies colorist scans film to HDCAM SR tape, making color decisions according to the D.P.'s specifications. Back on set, the production gets the full-range scan from telecine along with the color-correction information so they can see the colorist's work. Those color decisions are carried through the process in the format specified by the ASC's color decision list, or CDL, and are used for preview screenings and constitute the starting point for the actual DI.

The devil is in the details, of course, and for those details we turned to Glenn Kennel, LaserPacific's VP and general manager of feature film services.

FILM & VIDEO: So if I’m supervising post on a feature, what are you offering me now that was unavailable before?

GLENN KENNEL: We offered all the services before, but they weren’t linked together as tightly as they are with aIM. The pictures you see at the front end in dailies look like your intended product. And they look consistent at every display, from dailies through preview to DI and your final output deliverables.

For us, it meant rebuilding our dailies telecine process. Our telecines are now calibrated like a film scanner. That means we transfer the full range of the original negative. We store that on HDCAM SR tape, which is as close as you can come to a full digital record of the film. It’s 4:4:4 sampling, full 10-bit. Because our telecines are calibrated like a scanner, we’re essentially putting a scan file on tape in printing-density space. And in the telecine room, our colorist is grading the picture through a print film look-up table on a small projection screen. He’s not grading on a CRT monitor anymore, like traditional video dailies. It’s more like what we would use downstream in preview or DI, and it’s actually the same projector that we rent as part of our production dailies and playback system in the field.

What kind of projector is this?

We’re using a 1920×1080 Panasonic projector. It’s got an extended color gamut that’s very close to the film color gamut that we work toward in the DI suite, and very close to the digital-cinema color gamut of the DLP cinema projectors in our DI timing suites.

Is the look of the dailies becoming more important to the director and the cinematographer during production?

Yes. As everything is going digital, more and more people get to see the dailies, and more and more of the operations are being conducted in parallel. That’s what drove the need to go from film-printed dailies to digital dailies ‘ so editorial could be on board and running with it right away, so the director could see it right away, and so the studio production executives could be watching what’s going on. But with video dailies, it didn’t look like the final product. The editor and director were making decisions based on this video picture rather than the film picture. On many projects there is a real discontinuity when they come into the DI suite and see it for the first time on film, or for the first time being visualized for film, if you will.

So we deliver this dailies transfer to tape that gives us a scan record we can use to assemble the previews downstream. You could even finish it for film output that way. But typically we would go back and re-scan the select scenes after editorial was finished and reassemble that for the DI process. That’s why it’s critical that the telecine be calibrated to match the scanner. The color-correction decisions that are made in the dailies transfer are what we use to start the preview assembly, but it’s also the starting point for DI. You don’t have to start over at each step in the process, because we’re carrying color information from one step to the other. That’s where the color decision list comes in.

You mean the ASC CDL?

We’ve taken what they’ve started a step further and figured out a way to transport that from telecine to the field dailies system where we play it back, and also to the color-correctors we use in preview and DI. The nine parameters that the ASC defined for communication between color-correctors is the starting point, and figuring out how to get the boxes to talk to one another and transfer those parameters from one box to the other was a key piece. We worked with Pandora, who provides the color-corrector we use in telecine, we talked to Evertz, who basically builds the ALE and FLEx files that carry the timecode – and now carry the CDL information, as well – from telecine to the rest of the process. We also worked with Autodesk to incorporate CDL into Lustre, which is our primary platform for our preview and DI work.

And those are the three key hardware pieces that had to understand and pass along the CDL metadata.

Correct. The CDL is intended to be an open industry standard supported across all color-corrector platforms. But we focused our efforts on the ones that we’re using. And I know the ASC is also in discussions with other color-corrector manufacturers.

But this is a process you can control because it all takes place at your facility.

That’s the key. And it’s not that we’re trying to build a closed system. But to make it work today, we have to spend a lot of time calibrating all the equipment – the telecines and scanners, and all the displays we use in the process. To make it work with the CDL exchange we had to work with the manufacturers directly. And, frankly, it’s not fully implemented yet so we provide some extra glue to make it play together.

What is the field production system?

We worked with our colleagues at Kodak to take one of the Kodak digital cinema servers and rebuild it into a dailies player. That means very high bit rate, very wide color gamut, high contrast, capable of supporting full cinema quality on a big screen. And we added a software level that provides for flexible control, cataloging and organization of all the production dailies as they are shot. So you can build playlists, not only to look at a day’s work by camera or scene or by selects or other identification information, but you can also re-sort the files by continuity if you want to look at a particular scene that was shot over several days or, sometimes, weeks. What is actually stored is the full-range scan that we did in telecine, along with the color-correction information, so when you play it back it’s color-corrected through one of these print look-up tables and you see what the colorist saw in his dailies transfer. Now you can take that and print it up or down. You can look into the highlights or shadows to see what was captured on the original negative. The mechanism we provide is just a simple printer-lights control. If you decide that you like the shot printed differently from the way the colorist in telecine delivered it, you can save that new setting after you make the adjustments, and that is saved back in the CDL, which follows through to the rest of the process. We transport it using ALE files.

Is there a specification for how the cinematographer, on set with his laptop, makes the decisions that will be quantified in the CDL?

Cinematographers have different approaches. There are two or three common approaches, and we support all of them. Eventually, we hope the CDL will be built into [all of] the look-management or previsualization systems. Once you have calibrated look-management systems with a CDL output, we’ll take that right into telecine as the first step of the dailies.

So it wouldn’t matter to you how the CDL was created?

No. We have worked with customers who use the Kodak Look Management System. We’ve worked with people who use the Gamma & Density system. Frankly, on the last couple projects, we’ve worked with DPs who were using Photoshop and sending us JPEG proxies. In the case of Bolden!, for example – the project we’re doing right now with Vilmos Zsigmond – we brought him and his camera assistant into our telecine suite. We set up their laptops side by side with our reference still store and the projector we were using for the transfers, making sure that everything was matching for calibrated white point and the look of the pictures. Now, every day, they send us JPEG proxies from the set that we load into the still store and use as a visual reference for our grading. It has worked very well, but that system depends on the cooperation and communication we had up front to get their laptop and system calibrated.

So you’re already using a more-or-less complete version of this workflow?

Yes. Daryn Okada started shooting Harold & Kumar 2 in Louisiana in January and went through mid-March. We did the aIM dailies transfer for him, and he had one of our aIM dailies production systems on location. They finished principal photography in March. They’re now going through editorial, and we hope to bring them in for preview assembly within the next two months. And then about the time that project ended, we started Bolden!, which Vilmos Zsigmond is shooting in North Carolina, and we’re doing the same thing there – aIM dailies transfer, and delivering the files for playback on an aIM dailies system in the field. And that will also involve preview and final DI assembly later this year.

And if he’s happy with the process, I guess you’ve got the Good Housekeeping seal of approval.

Well, he’s got loads of experience and he’s as demanding in terms of quality as anyone out there. We worked with him last year on Black Dahlia, which we finished at 4K. He’s definitely very experienced, very meticulous, a real craftsman when it comes to lighting and the whole trade of cinematography. He’s just as good as they come. He came to us and said, “I’ve got to have your aIM system.” We talked to him a little bit last year as we were developing it, so this was good timing for both of us.