The Challenges of Digital Projection, Part 3: Preservation

In my first two pieces on the conversion to digital projection, I covered what the conversion would do to theaters and how it would likely effect small distributors and classic film presentation. In this final installment, I discuss the scariest part of all: Will studios and archives be able to preserve their motion pictures in bits as well as they now preserve them on film?

I owe a lot from this series to Kristin Thompson and David Bordwell’s blog, Observations on film art. Bordwell did an invaluable series on the digital transition named “Pandora’s digital box.” I found his piece on preserving digital moving images exceptionally informative, and depressing.

To sum it up: We know now how to preserve film. You can put the cans in a climate-controlled room and, as long as you keep paying the electricity bill, they’re preserved. But with digital, the hardware and software formats change constantly, increasing odds that you’ll dig out a 50-year-old title and have no way to read it. And the physical media that the bits are stored on may not be as stable as film.

Archivists estimate the life of any digital platform to be less than ten years, sometimes less than five. All hard drives fail sooner or later, and they need to be run periodically to lubricate themselves. Tape degradation can be quite quick; one expert found that 40 % of tapes from digital intermediate houses had missing frames or corrupted data. Most of the tapes were only nine months old.

The obvious solution, preserve everything in film, will only work for a short time. In a few years, there may not be enough of a market for film and film developing to keep the labs open. Old pictures, already on film, will last until the prints wear out. New ones, shot digitally, will never be transferred.

Bad as it sounds, I can’t help feeling some reasons for optimism. Digital has some inherent preservation advantages. Because you can store more information into smaller areas, it requires less storage space. You can make an exact copy of a digital source–something that’s not possible in any analog medium.

I’m no expert in preservation, but I’ve been following and reporting on the evolution of digital technology for a quarter century. And I can’t help thinking that an organized solution can reasonably guarantee digital motion picture preservation for the foreseeable future.

What follows is my idea for digital motion picture preservation. I hope that people in the business will read this, and then explain the holes are in my theory. Even better, I’d like one to say “Yeah, we’re working on that.”

As long as possible, any digital preservation technique should be done in parallel to preserving pictures–even those shot digitally–on film. For long-term protection, no cutting-edge technology can be as dependable as what we already know.

The Committee

A committee of some sort would have to be created to oversee the development and maintenance of a digital motion picture preservation system. The committee would develop and approve standards (or appoint engineers to do so), and over the long term insure backward compatibility. Let’s call this group the Digital Preservation Committee (DPC).

I’d put the International Federation of Film Archives in charge of appointing and overseeing the DPC. Major studios, who would also benefit, might help with the financing.

The DPC would control and standardize the type of physical media on which the bits are stored, the hardware that can read that media, and the software that will turn those bits nto moving images and sound. As the technology changes, the DPC will also enforce backward compatibility.

One issue the committee won’t have to worry about is pleasing theater owners or home video consumers. The hardware and software they certify will be used exclusively for archives. Transferring it to presentation media won’t be a major problem.

Media

Digital media tends to fall into one of two categories: Either it’s built to be easily erasable and reusable, such as hard drives and flash RAM, or it’s designed for mass-produced publication at the lowest possible cost, such as CDs, DVD, and Blu-ray discs. Cheap, or erasable? For long-term archival needs, that’s not an acceptable choice.

So the DPC must develop a storage medium that is permanent and resistant to damage. I would guess that they’d pick some kind of optical disc, made from a material that’s not easily scratchable and that takes a very long time to rot. Because it would have to hold a great many bits, the discs would probably be much wider in diameter than a Blu-ray, and able to carry data on both sides.

Of course, as a safety measure, multiple copies should be preserved in different archives.

Hardware

Developing a new media involves developing the way the media is written to and read. And reading, far more than writing, is a separate issue that the DPC would have to deal with.

New standards inevitably replace old ones–especially with digital technology. And if someone isn’t careful, the old standards become unreadable. The committee must therefore make sure that as the technology advances, there are always machines that can read all past DPC-certified mediums.

This isn’t as impossible as some people believe. Every Blu-ray player can play DVDs and CDs. Backward compatibility issues become more complicated if the physical dimensions of the media changes, but they don’t become insurmountable. You can buy a Blu-ray player that can manage VHS.

As an extra safety measure, every archive storing the media would have to also store a book–on paper–explaining how the media works and how to build a playback machine.

Software

That book would also have to explain the algorithms for turning the bits on the media into moving images and sound.

The coding method should be as simple as possible, and as elastic. If there has to be a maximum resolution, it must be very, very high. The longer you have to go before rewriting the code, the better. And if it must be changed, the DPC will have to enforce backward compatibility here, as well. Just as Photoshop can still open a .pcx file, new decoding software would have to support old formats to gain the committee’s approval.

Ideally, the standard should have no compression. If that’s entirely impractical, the compression must be lossless. Preservationists should not be throwing away bits.

And it absolutely must contain no encryption. The goal is to make these images readable, not impenetrable. Since the media will only be playable on certain machines kept only in archives, piracy would not be a serious problem.

As long as the DPC does its job, the films would be preserved. You could pull discs from the shelf, insert them into the playback machine, and either watch the picture, or transfer it to a more commercial medium, such as Blu-ray, DCP, or something we haven’t yet invented.

If you know what’s wrong with this idea, please tell me.

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