This is the second part of our “Playing for Keeps” series on film and digital preservation. Read the first part, on film preservation, here.
A decade and half ago, the world started transitioning toward digital capture, and the film vs. digital debate fired up. The main focus of attention was image capture—at the center of the conversation were topics such as resolution, dynamic range and other comparisons between digital image creation and the gold standard of film capture. Yet the question of preservation and archiving of digital movies remained in the background.
Take Christopher Kenneally’s seminal 2012 film Side by Side as an example. The film follows an ideal production workflow, from image origination to editing, color correction to exhibition, featuring Keanu Reeves interviewing prominent directors, cinematographers, editors and other key players in the production and post-production chain. However, attention to the impact of the digital revolution on how moving images can be preserved and made available for posterity is very marginal—only one archivist/preservationist is interviewed.
Why? Some say we’re still locked into the habits of a “film approach” to digital matters. Film—as discussed at length in the first part of this preservation feature, in MovieMaker’s Winter 2017 issue—allows plenty of leeway to negligent archivists and busy moviemakers. Reels of film forgotten on a shelf for decades still have a good chance of remaining in nearly pristine condition. Digital doesn’t allow that. When images are captured as digital files—by nature transient and fragile—the game changes. In this context, the film motto “store and ignore” is a recipe for disaster.
So in this new paradigm, digital preservation constantly requires moviemakers to be proactive, with fast migration from one format or medium to a newer one. Procrastination and faith in time’s forgiveness is not allowed. Instead, in order to avoid catastrophe, planning is essential in the production phase. Moviemakers have to consider data storage and data retrievability in the short term, which means reflecting more than ever on how to guarantee long-term preservation and accessibility to their work.
While we’ve come a long way with film preservation, we cannot say the same for digital preservation. Digital technology is ever-evolving and nothing is set in stone, not even basic standards. This makes long-term preservation of films shot digitally uniquely challenging. Before going deeper into digital preservation, though, it’s worth talking about videotape preservation, since tape was the first alternative to film.
Unless you came into moviemaking in the last few years, you’ve probably shot on several formats: from the most recent high-definition HDCAM, HDCAM SR and DVCPRO HD, to the earlier MiniDV, DVCPRO, DVCAM and D tapes, common in the late 1990s and 2000s. If you are a little older, you might have recorded on analog tapes such as Video8, Hi8, VHS, S-VHS, Betacam and Betacam SP, used throughout the 1980s and 1990s, or the defunct Betamax, introduced in 1975—or even 3/4” U-matic, which was introduced on the market in the early 1970s and used until the end of the analog era. Other tape formats have been used extensively as mastering (rather than capture) media, Digibeta above all.
Tape can be a reliable medium, but certainly not as reliable as film, and cannot be considered safe for long-term storage of moving images. The main threat to videotape is media and equipment obsolescence. So many different formats have replaced one another over the years, and each of them is dependent on different playback technology. Playback machines in working condition are becoming increasingly scarce, and spare parts and experienced technicians are difficult to find. Tape, which manufacturers guarantee to last about 30 years—a much shorter lifespan than film—might very likely outlive its recording and playback technology.
The first recommendation for preserving tape content is to transfer it to digital files as soon as possible, especially for the older analog formats that are now obsolete. Images on analog tapes should be captured as 10-bit uncompressed video, which retains all the visual information present in the initial capture process. However, if the large dimensions of uncompressed files make storage particularly difficult or expensive, then mathematically lossless compression (e.g. JPEG 2000) might be a reasonable second best option. Whenever possible, digital tapes should be captured in their native format (e.g. DV in case of MiniDV) without further transcoding, so as to maintain the original specifications of the digital content. This is possible for some digital tape-based formats (e.g. DV or HDCAM), but not all. For instance, Digital Betacam doesn’t allow access to the digital video as stored on tape, and should be captured as 10-bit uncompressed files.
If you do not have more than a couple of formats to transfer, but own a high number of tapes, you might try to digitize your tapes at home with the right computer equipment and a camcorder or tape deck in working condition. (Tape decks, originally hugely expensive, are much cheaper these days on the second-hand market.) If the effort and investment do not seem worth it, you could send your tapes to a vendor. Costs vary wildly, from $15 to $100 per tape or per hour of footage, depending on the tape format and number of tapes or hours to be transferred. Depending on whether you are digitizing to uncompressed or compressed, or keeping the native codec, you might end up with very different file sizes and storage needs. On average, uncompressed 10-bit digitization corresponds to 100GB per hour of video, lossless compression to about half of that. DV captured in the native encoding corresponds to about 13GB per hour of video.
While planning for digitization, be aware of other factors that could shorten or extend a tape’s life. Videotape consists of a thin polyester base coated with metal oxide particles embedded in a binder layer. The binder can degrade and shed, and the magnetic particles can corrode. This leads, in both cases, to a loss of signal. The stability of the binder layer varies by tape manufacturer and tape format, but good storage conditions will extend the life of any tape. ISO standards recommend relatively cool storage conditions for tape: Maximum temperature should not exceed 73 degrees Fahrenheit and minimum should not go below 46 degrees. Relative humidity should not exceed 50 percent, preferably below 30 percent. According to ISO, when temperature and relative humidity are maximum 73 degrees Fahrenheit and 50 percent (medium-term storage conditions), the expected useful life of a tape is 10 years. At lower temperature and/or relative humidity—for instance below 63 degrees and 30 percent (extended-term storage conditions)—the life of a tape could be extended to up to 50 years.
Magnetic fields—such as those present near motors and transformers, or produced by some headphones, speakers, microphones, computer monitors, magnetic cabinet latches or magnetized tools—could affect the signal on a tape and should be avoided. Badly maintained equipment can also damage or stretch tapes—the smaller and thinner the tape, the weaker it is, so pay particular attention to small tape formats such as Video8, Hi8, Digital8 and MiniDV. Tapes should be kept out of direct sunlight and away from dust. Also, they should be stored upright rather than lying horizontally, and be rewound after use in order to avoid uneven tape pack.
Now, raise your hand if you have never had a hard drive fail, or if you’ve misplaced a digital file because of a mistyped name. It’s traumatic—days or months of work could be lost in a matter of seconds. Digital doesn’t seem to always fulfill the promise to make our lives easier. Technology has made capture cheaper, and footage shot in production has exponentially grown. All of a sudden, you end up with several terabytes (TB) of files, and things might start to get messy.
Once you have digitized all your tapes, you need to keep track of where the files live. Now more than ever, you need to be organized. Develop naming conventions and rename files to a standard that is clearly documented. Use spreadsheets, keep a log of your tapes, label your tapes following a well-thought-out system, then stick to that system. Metadata is one of the most crucial aspects of dealing with digitized files.