Nitrate film preservation

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Although not manufactured since the early 1950s, nitrate-based film footage still exists in collections around the world.

We find owners of historic motion picture film ranging from corporations established decades ago to small museums. Often, they either don’t know if their holdings include nitrate, or they’re aware but unsure of what to do with it. In those cases, they may be resorting to solutions like storing the film in a freezer. I encourage you to read California’s Marin County Museum nitrate film story, written by museum staff, to see if your situation is similar.

Neglecting historical nitrate film footage in your collection?

Cellulose nitrate base was eliminated by film manufacturers because it’s highly flammable and nearly impossible to extinguish if a fire does occur. Nitrate film creates its own oxygen source and will continue burning, even submerged in water. The flames release poisonous gases and toxic smoke. Improper handling can, and has, posed a significant risk to projection and storage facilities, people and the environment.

PRO-TEK is one of the few remaining service providers that can identify, restore and preserve historical footage captured on nitrate cellulose from the earliest days of film-making. We’ve inspected and restored old films that are considered some of the most important movies in American cultural history, including many Oscar winners. We also work with small organizations, helping local historical societies deal with just one roll of nitrate film.

As such, we’re working to alleviate the fear and uncertainty expressed by many owners of nitrate film, while creating a sense of urgency and priority to take care of it now. With that in mind, following is some basic information on how to approach the nitrate film in your collection.

Identifying nitrate film

How do you know if that old film footage you have is nitrate? Start with these three criteria, and if any questions remain, have it assessed by nitrate experts:

  • Film width or gauge—Most nitrate film will be 35mm wide (or slightly less due to shrinkage), though some exceptions do exist.
  • Visual inspection—Most film stock made after 1920 was marked along the edges. You may see “Nitrate Film”, “Safety Film” or just the letter “S”, which also was used on safety film. Safety film was the name given to cellulose acetate, the base material that replaced cellulose nitrate.
  • History—If your footage was created before 1950, chances are good it’s on nitrate-based film. If your footage was captured in the early 1950s, it could be either nitrate or safety stock, as film manufacturing in the United States switched to acetate at the start of the decade. In Europe, nitrate film continued to be produced well into the 50s.

Because of exceptions to these criteria, a professional, informed assessment is always valuable, especially in ambiguous situations.

Nitrate shipping and handling requirements

As a hazardous material, cellulose nitrate film cannot be shipped without certification. It’s subject to a variety of transportation rules and regulations, and PRO-TEK is well-versed and experienced in all of them.

Some of the regulatory agencies that govern nitrate film handling include the National Fire Protection Association (NFPA), US Department of Transportation and International Air Transport Association (IATA). While US DOT regulates domestic transport, most carriers use the more stringent IATA rules even within the United States, which is what PRO-TEK follows.


Nitrate restoration success depends on the condition of the film. A visual inspection will reveal the degree of decomposition, which can include a noxious brown powder or a sticky, bubbly appearance. While accustomed to handling nitrate film in various stages of degradation, it always saddens us to see film that has deteriorated beyond repair. Yet we have ways of bringing old images back to life, so don’t give up hope until we’ve had the chance to inspect your footage.

Because nitrate-based films are unstable, it’s a good idea to make copies of all viable footage. PRO-TEK is one of the only providers of digitization services for nitrate film. Viable, first-generation film is often worth preserving (more on that later). Otherwise, we can dispose of any originals that are severely degraded or unwanted.


The risks associated with nitrate film are greater for collection owners with a large amount of nitrate in their holdings, and with any nitrate that is improperly stored and handled.

Basic criteria for safely storing a limited amount of nitrate film:

  • Remove from air-tight storage containers and use ventilated storage containers, clearly labeled as holding nitrate film, with flammability warnings.
  • Store in a place that is consistently cool and dry, far away from any heat sources. Do not store in a freezer that also holds food and gets regular use by people.
  • Do not store other collection items in the same area as the nitrate items.

Nitrate film must be segregated, not only due to its flammability but because it off-gases over time. These gases are poisonous; plus they accelerate the deterioration of other items, especially acetate or polyester film that is stored in the same area.

As already discussed, your best option may be to digitize the imagery and properly dispose of the nitrate originals.

PRO-TEK is one of the few places left in the world that manages nitrate film vaults for clients. The nitrate vaults are located several miles away from our Burbank campus. All nitrate storages must adhere to strict NFPA 40 guidelines as to how much nitrate film can be stored in a building at any one time, vault specifications, fireproofing and so on. We can assess your needs and help you understand your options.


The process of disposing of nitrate film presents its own set of both practical challenges and legal and regulatory requirements. The recommended method of disposal for nitrate film is specialized, high-temperature incineration that is supervised and done by a certified waste disposal company.

Never discard nitrate film in ordinary trash containers or routine disposals, and NEVER attempt to burn it!

Turn to archiving professionals like PRO-TEK first. We’ll inspect and assess your nitrate and arrange for safe, legal disposal if needed.


While nitrate was an unstable, combustible film base, it was also highly desirable because of the aesthetic quality of the images it produced. Nitrate’s silver content gave black-and-white film a luminous contrast between light and dark.  The past few years have seen renewed interest in early films, and several repertory houses and other institutions have retrofitted their theatres to safely project original nitrate prints. Collection owners trust PRO-TEK to prepare and ship their rare, valuable prints to these festivals and retrospectives around the world.

Your historical nitrate film may not have artistic, entertainment value but it will certainly hold cultural and historical value as part of the early days of motion picture film-making. We’re fortunate to have many film historians on staff whose expertise can help assess your assets and bring them back to life, even if it’s solely for digital publication and access. We offer a rare mix of knowledge and training in the old techniques, while using modern equipment and tools.

I will finish by stating what I always say to clients with nitrate film in their collection:

Respect the potential hazards of nitrate, but don’t be afraid! Most importantly, if you’ve been neglecting old film footage that you know or suspect to be nitrate, it’s time to assess those assets and develop a plan of action, once and for all.

Learn more about PRO-TEK’s nitrate film services here or contact us to answer any questions you may have.

Following is additional information from Kodak and AMIA (Association of Moving Image Archivists) on handling nitrate film:

Tim Knapp

Tim Knapp

Tim Knapp is EVP of Media & Archive services at LAC Group. He brings more than 30 years of experience in motion and still imaging – first in film, and most recently in digital. Tim has an extensive and wide-ranging understanding of the capabilities and challenges of film and video, including the issues and opportunities it presents for archivists as they face aging media libraries and an increasingly digital future.

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