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Film Preservation 101: A Brief Guide to Keeping Your Films Alive Indefinitely (Part One)

Film Preservation 101: A Brief Guide to Keeping Your Films Alive Indefinitely (Part One)


This is the first part of our “Playing for Keeps” series on film and digital preservation. Read the second part, on video and digital preservation, here.

Once a film is distributed, its makers tend to move on; with few exceptions they don’t spend a lot of time dwelling on where the product of their years of hard work will end up.

The unfortunate reality is that most moviemakers overlook proper planning for the post-exhibition life of their films. Usually the materials that comprise the original exhibition copy are left behind until something new stirs interest in that work again. Then a search for those materials starts. In some lucky cases, the elements were properly taken care of and immediately available. In other cases they are difficult to track down or, worse, either lost or permanently degraded. Film can decay, digital data can get corrupted or become obsolete and then irretrievable. What can be done then? Often, sadly, nothing—it’s too late.

In order to avoid that scenario, some filmmakers keep their camera negatives or digital masters stored safely, more or less, at home, or pay a company to provide professional storage. For films shot on film, negatives are likely to be left on a shelf in a film laboratory. Their owners are reminded of them when the lab decides to charge for storage, or, more importantly, when the lab closes down.

The transition to digital filmmaking, with its lack of a physical object to rely on, has made preservation issues even more pressing. In the production phase moviemakers are now confronted with storage and data availability issues; that reality is causing them to be proactive about ensuring preservation and longterm accessibility to their works.

Archiving and preservation are the last steps in the life of a movie. They can be the first steps of a new life, too, since proper preservation guarantees that a film can be seen long after its original release. Unfortunately, preservation also requires time for proper planning and financial resources. So let’s run through some basic directions on how to preserve your films, whether they’re digital or shot on film. In this first part, we start with preservation of physical film, where best practices and standards have been codified over several decades. The second part, to appear in the Spring, 2017 issue of MovieMaker, will focus on video and digital preservation.

What Are You Preserving?

Film is still the best medium for the long-term preservation of moving images, so if you are at all concerned about the shelf life of your work, it might be wise to stick to film. After all, several Lumière and Edison film copies from the late 1890s are still in decent shape today (and for most of their lives they have not even been conserved in proper conditions of temperature and humidity!).

If you are starting from an edited camera negative, the bare minimum you’ll need to create for preservation purposes is a color intermediate positive (or black-and-white fine grain master). Additional elements include a preservation negative from the intermediate positive, as well as a good-looking print for exhibition and color reference. The printing strips or light sheets created by the laboratory for such elements should be kept for future access, to be used, for instance, when a new print is needed.

If your movie was shot on film but went through digital intermediate post-production, it either ended up on film again with the creation of an intermediate negative and one or more prints, or stayed digital, as with the creation of a DCP. In the first case, the negative created via digital recorder should be on polyester stock and might be considered your back-up negative. If financially feasible, you could also create an intermediate positive. In the second case, for preservation purposes you can either go back to film, creating an intermediate negative via digital recorder, or stay digital, safeguarding your digital exhibition element and master files in the form of digital data. (More on that next issue!)

Temperature and Humidity

Temperature and relative humidity are key factors in film conservation. As long as film is kept in a cool and dry environment, and not mishandled, it can be expected to live very long. Room conditions can be good enough for materials that are considered chemically stable, such as black-and-white silver images on polyester base. Such images should last 500 years or longer when stored properly.

On the other hand, color materials require colder storage than black and white materials, since color dyes are chemically much less stable than silver grains. Similarly, acetate film stock is not as stable as polyester and warrants cool storage and low humidity levels. ISO standards consider temperatures between 60 and 73 degrees Fahrenheit and 30-50 percent relative humidity (RH) acceptable for black and white polyester stock, and recommend temperatures between 32 and 46 degrees Fahrenheit and 30-50 percent RH for acetate and color stock. Considering that all camera negative stocks come on acetate base, while prints and lab intermediate materials are commonly printed on polyester stock, your camera negatives are the elements in need of the most careful attention.

According to accelerated aging tests conducted by the  IPI (Image Permanence Institute) in Rochester, New York, fresh acetate stored at 68 degrees Fahrenheit and 50 percent RH will likely last 50 years before developing vinegar syndrome—the infamous acetate base decay where acetic acid is released with progressive embrittlement, distortion and shrinkage of the film. However, at 50 degrees Fahrenheit and 40 percent RH, the same roll of film would last over 250 years. If the same fresh acetate is kept in typical archival storage conditions—for instance, at 40 degrees Fahrenheit and 30 percent RH—it could last well over 800 years before developing the first signs of decay!

Under the same environmental conditions, color film would last for about 1,500 years before dyes would fade to a noticeable 30 percent density loss.  This means that for every roll of new film conserved in cold storage, we can safely, as they say, “store and ignore”—i.e. no particular action other than monitoring the temperature and humidity is required to guarantee survival of the film itself.

The best (but most expensive) route for color film preservation would be color separations. This means that each color channel—red, green and blue—is printed on black-and-white stock.  Given that this means tripling costs, though, preservation via separations is rarely done even for archival institutions, much less independent filmmakers.

Home Storage Advice

Most moviemakers aren’t lucky enough to have their films stored in temperature- and humidity-controlled vaults. What to do, then, if you are keeping your films at home?

Monitor environmental conditions and avoid humid basements or hot attics. You can use the IPI calculator available on to get an idea of how good or bad your storage conditions are, and how long film under those conditions is expected to last. In general, low temperatures have the greatest potential to maximize the medium’s stability. Wider relative humidity ranges can be tolerated, as long as they are between 20 and 50 percent. If relative humidity goes above 60 or 70 percent for extended periods of time, then the film is prone to developing mold. Not surprisingly, tropical climates are particularly unsuitable for storing films.

When you cannot follow ideal storage guidelines, strive for the best storage conditions available to your means and your goals. Again, the most precious element is the camera negative, which, being on acetate stock, should be kept at cold temperatures. If you have a small amount of film to conserve, or such film is already degrading, then you can store it in a fridge or freezer. Sub-freezing temperatures stabilize film that has reached the autocatalytic point of acetate deterioration and has started developing vinegar syndrome.

In this case, you need to properly prepare your reels: Carefully seal them in moisture-proof housing (e.g. in two ziplock bags, one inside the other) before putting them in the fridge or freezer. It is important to not seal the film in hot and humid conditions, to prevent excessive moisture inside the sealed packaging. (Any paper document should be removed from film cans and stored separately. Likewise, any plastic wrapping around brand new film should be removed.)

When removing the film from low temperature storage, be careful not to expose it to water condensation, which could damage its emulsion. Leave it in its package, and let it acclimatize at room temperature for 24 hours before winding it.

As a back-up of the camera negative, you should create other elements as part of the preservation workflow. If the film has sound, don’t forget to preserve the sound on film, too. The new elements should be printed on polyester stock, which is more forgiving of warmer and more humid storage conditions.

If every room in your home has a less-than-suitable temperature or relative humidity, and you cannot find any other safe haven for your film, an alternative to consider is contacting a storage facility.

The temperature and humidity controlled vaults at George Eastman Museum

What’ll It Cost?

Costs can vary considerably depending on the lab. Charges for color and black-and-white elements can also vary, but in recent years the gap between the two has significantly narrowed. As a very rough estimate, in order to photochemically preserve 1,000 feet of 16mm black-and-white or color camera negative film (running almost 30 minutes at 24fps), the creation of a fine grain master would cost between $1,500 and $2,500. The creation of a duplicate negative would cost approximately the same, and the creation of an answer print would be between $600 and $1,500. Creation of a back up of the soundtrack negative would be between $700 and $1,000. This means that creation of preservation elements for a 30-minute 16mm camera original would approximately cost from $2,200 to $3,500 for partial preservation (creation of an intermediate positive and a sound positive), and from $4,300 to $7,500 for full preservation (also an intermediate negative and a print).

In case of a digital intermediate workflow, using a digital recorder to shoot back on film can be costly. Not all recorders are able to shoot on 16mm and some give only the option of shooting on 35mm, which means usage of more film and higher costs. Keeping our example, you could create a 1,000-feet 16mm intermediate negative and print via film-out for about $6,000, or slightly less.

Of course, these are rough estimates. Talk with several labs, get quotes and then make a decision based not only on price but also quality standards, delivery times and customer service. At any rate, creating preservation elements can be a considerable investment, and this should be taken into account already when planning for a film production. Despite high upfront costs, preserving on film has the advantage that, once the preservation elements are created, maintenance costs are low.

You could even consider donating your films to an archive, with the option of accessing them at any time you need to do so. Archives give preference to donations over loans, and might be open to acquiring your work, especially if they consider it in line with their collecting interests and worthy of future generations. It’s easier to start a conversation with a local, regional or specialized archive, rather than trying to contact one of the “big five” American film archives (George Eastman Museum, Library of Congress, MoMA, UCLA and Academy).

And who knows? One day that archive might even apply for a grant to preserve your work on film… even if that seems, now, like a long shot. MM

This article appears in MovieMaker‘s Winter 2017 issue. Read the second part, which appears in the Spring 2017 issue, here.

Top photograph from Bill Morrison’s 2003 film “The Mesmerist.”

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