Video and Digital Preservation 101: A Brief Guide to Keeping Your Films Alive Indefinitely (Part Two)

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Studios try to keep and archive all the material that is shot on a set, creating massive amounts of content. This means that each production needs huge amounts of digital storage. If the budget allows it, some studios even shoot the most relevant of those files on film, because it’s a trusted preservation medium and relatively inexpensive in the long term. As an independent moviemaker, you probably can’t afford to keep everything you shoot, much less transfer it to film. So selection becomes key.

During production, you will need to decide what to keep in terms of footage. After the film is shot, you’ll create several versions of the same files during post, as well. If you’re sure you won’t need any more of the footage that didn’t make it into the final edit, you might decide to let it go and not archive it.

In a high-end post-production workflow, the camera footage selected for the final edit is color-graded. It generates the DSM (Digital Source Master), which is the master copy of the finished film (or, in film terms, the fine grain master/intermediate positive). Together with that, you want to also retain the DCDM (Digital Cinema Distribution Master) and the DCP (Digital Cinema Package), a high-quality digital projection element for theatrical exhibition. For archival purposes, the DCP should be unencrypted, or, if encrypted, should be accompanied by the software to generate a KDM (Key Delivery Message), the security key to play the film.

Just as it would be a mistake to select a projection print of a film as the only element to be archived and preserved, you shouldn’t only digitally archive a DCP (especially an encrypted DCP). Of course, while a DCP is compressed and needs relatively little storage space—approximately 150/180GB per feature film—a DCDM can take much more space: approximately 2TB for a 2K feature film.

For every film, plan for several TB of digital storage. Do not expect to save all your data on a single portable hard drive and be safe. Drives fail. Solid state drives (SSDs) are a more trusted storage medium than magnetic hard drives because they don’t have moving parts. However, SSDs are still considerably more expensive per TB than magnetic hard drives. Currently, for approximately $70-90, you can buy 120GB of storage on a solid state portable drive vs. 2TB on a portable magnetic drive. To buy 2TB of storage on solid state portable drive, you would need to spend approximately $700! You might consider an inexpensive bare drive as an alternative. Or you might consider cloud storage, though that’s not necessarily cheap and might raise some security and long-term accessibility concerns.

Currently the cheapest and most reliable option for medium-term storage is Linear Tape-Open (LTO) tape, a solution widely adopted by the industry. Tapes of the latest generation (LTO-7) cost $130 per tape (less if bought in bulk) and can hold up to 6TB of data. Manufacturers guarantee the tape stock can last up to 30 years, but new generations of LTO tapes are introduced every two to three years and have limited backward compatibility (up to two generations), making tapes and tape decks soon obsolete. So you should still migrate your data every three to five years to the next tape generation or every other generation. You could pay a vendor to copy and migrate your data, or you could do it at home. In order to use LTO technology, you need to buy tapes and a tape drive, and be prepared to upgrade to new hardware in just a few years. You’d be hard-pressed to purchase a tape drive for the current generation of tapes for under $3,000. Drives for the generation immediately before can be purchased for about the half of this price.

Best practices recommend storing data according to the principles of redundancy and geographic dispersion—so you want to create several back-ups of the same files, possibly on different storage mediums, and stored in different places. Make sure that the data is not accidentally altered or corrupted when moving or copying files by running specific file verification software (also called checksum software) to confirm data integrity. And remember to constantly document where your data is stored, or finding it again might become a daunting task! If you have lots and lots of data, digital asset management software will certainly help.

None of this comes at a cheap price—or by little effort. There’s no way around it, though: Neglect preservation and your work will be unwatchable before you know it. The best option to safeguard the future of your films is to be your own archivist.

Be proactive. Do it now.

Essential Reading

“The Digital Dilemma,” published in 2007 by the Science and Technology Council of the Academy of Motion Picture Arts and Sciences

The Federal Agencies Digital Guidelines Initiative’s website MM

 This article appears in MovieMaker’s Spring 2017 issue. Illustration by Jade Schulz.

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1 Comment

  1. Bridget Holland

    September 2, 2018 at 7:05 pm

    Daniela, congratulations on two articles which address the real issues in making sure your content lasts!
    If only people thought about this when they first start a project – the cost is a minimal part of overall movie-making budget.

    Open disclosure – Preferred Media stores film, tape and digital content for many Australian producers. On the whole we’ve found they want to concentrate on projects and let us look after preservation.

    Our digital backup and archive services make ‘store and ignore’ a real option for digital content as well. Pay for up to 5 years in advance, hand everything over and we sort it all out for you. Plus you get online web-files and you can get your original hires back whenever you need it.

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