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Preparing film for long term storage in freezer?

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  • Preparing film for long term storage in freezer?

    I'm preparing to put my collection of acetates into the freezer for long term storage 5+ years.

    Is there anything I should treat them with before freezing them?

    Freezing puts mold spores into hibernation so I don't believe I have to worry about them growing in the freezer. The other advice I've been given is to seal them completely air tight and try to suck most out of the air out of the storage container.

    I'm not going to leave silica gel tabs in the bag because that will dry them out, but I do have the opportunity to leave camphor tabs under the covers before I seal them up. I'm not sure how camphor would hold up in the freezer though.

    Finally I'm using archival non acidic tape to seal them, although not sure if the tape will hold up in freezing temps. I'm using plastic bags meant for the freezer for added thickness. I'm not going to bother cleaning them until I'm ready to project them.

    Missing anything before I seal them up for good?

  • #2
    I found some good info today searching around and reading old websites and books.

    Turns out there is no reason to store acetates in the freezer. That is more for nitrates. Library of Congress keeps their acetate films at 41- 43 degrees and its nitrate at 38 degrees. I've been reading that cold storage in the fridge will greatly reduce the rate of dye fading and vinegar syndrome, so refrigerating decades-old fading triacetate prints will help keep them in their present state without further deterioration.

    Here is so more good literature to read.

    These are my steps I've wrote down today for how I'm going to tackle my collection.

    Step 1: Preparing Proper Climate

    This is essential part of the equation which can destroy your film when done wrong. Before putting away in long term storage or sealing away, you have to make sure that your film has adapted to a stable temperature and low humidity. It must be kept at around 35% humidity for two weeks straight before going into longterm storage. This is to ensure that you don't trap any moisture in the bag before storage

    Step 2: Pre-Treatment

    It's important that in order to prevent vinegar syndrome that you leave a few sieves in your canisters. Molecular Sieves will adsorb excess moisture, and any acid vapors that may start to form. However the known problem with using them is that if your film is already brittle, it will further desiccate the film, causing curl, brittleness and shrinkage. Before longterm storage you want to let camphor tabs evaporate inside your film canisters at room temperature, and let your film absorb the camphor before it's put away in storage to ensure it doesn't shrink.

    If you want to go even more crazy you can clean your film with vitafilm (also has camphor in it) which also removes mold, but mold is not something I would worry about too much. Cold temperatures do not kill mold but they put spores into hibernation. If the bags are sealed they won't spread to your collection.

    Step 3: Storing Your Film

    This is the last and final step to creating a proper longterm storage environment for your film. Many believe that humidity in a fridge matters, or that you need a perfect vacuum seal or your film will grow mold or it will get ruined from frost crystals and moisture. This is where the molecular sieves come into play. Sealing your film in a bag and leaving a few in your canisters will both prevent VS and keep away excess moisture but don't overdo it. However they only last six months until they have to be replaced again, so if your collection is large this can be a pain but doable.

    A lot of consumer fridges have separate drawers at the bottom. You may want to isolate VS in those drawers. As long as the bag is sealed though I wouldn't worry about it too much. Then stack flat horizontally and not vertically. You may benefit from thicker freezer bags even if kept in fridge.


    Now your films will be ready to be enjoyed or archived many decades from now. Fresh film stored at normal household conditions (70°F and 50% RH) will have an average lifespan of 40 to 50 years before significant signs of decay occur (e.g., vinegar syndrome and color dyes density loss). Reducing the temperature by 15 degrees Fahrenheit increases that number to 100-125 years.

    In my case I am building a setup which won't be completed for about 4-6 years from now. My entire collection ranges from 1940's through early 1960's and all of them have varying degrees of shrinking, decay, vinegar smell some faint and some strong.


    • #3
      Well I'm back with another update and more research I have done today.

      The above information still applies, but I may actually recommend freezing film instead of putting them in the fridge based on what I've read. While putting in the fridge does work to preserve film, you also have to keep film stored at warmer temps at much lower humidity and this harder to do.

      "According to the Image Permanence Institute, acetate-based motion picture film has a lifespan of 40 to 50 years when stored in normal household conditions (70 degrees F and 50% RH) – that is, before it begins to exhibit signs of deterioration. It is interesting to note that a good portion of vintage films are already 50 years old or older! The clock is not just ticking; the alarm has sounded."

      The Image Permanence Institute recommends the following ideal storage conditions for acetate-based film:

      For black-and-white film:

      36 degrees F maximum temperature for 50% maximum RH
      41 degrees F maximum temperature for 40% maximum RH
      45 degrees F maximum temperature for 30% maximum RH

      For color film:

      14 degrees F maximum temperature for 50% maximum RH
      27 degrees F maximum temperature for 40% maximum RH
      36 degrees F maximum temperature for 30% maximum RH

      As you can imagine for color films that are kept in a domestic fridge, your humidity level would have to be really low. You can avoid damage to film stock by transitioning from fridge first and then freezer. Same in reverse.

      Here is a film storage calculator to determine whether you are keeping in proper conditions. Acetates stored at 0 degrees F at 70% humidity would take 5,000 years to develop VS. Acetates which have already started degrading at that humidity level would last another 200 years. Drop it to 50% and it could last another 1537 years. Temperature matters much more.

      You actually want some moisture. "Film with low moisture content can be more susceptible to brittleness at low temperature
      Film with high moisture content can be susceptible to mechanical damage (gelatin softening, blocking) at warm temperature. Due to the autocatalytic deterioration mechanism, already degrading acetate materials require stringent storage conditions. Only cold and frozen storage can stabilize degrading acetate film."
      Last edited by Ben Klesc; July 13, 2021, 12:25 PM.


      • #4

        Thank you for posting your research. My films have already taken over closet I have to think about sneaking a few into the fridge!


        • #5
          That'a right I may have to buy less food from now on so I have extra room.

          I noticed one minor mistake. I wrote that molecular sieves only last six months. Silica gels packets should be replaced twice a year, but Kodak's specific molecular sieves I'm reading are advertised for lasting 2-3 years before needing replacement.

          I would really love to archive my 8/16mm home movies in 4K resolution. I am in the process of building a rig for pointing a camera into the projector itself. Right now the price for 4K cameras with 4:2:2 raw video (essential for post process) are very high priced. I suspect this will come down over the next 4-5 years as technology always does. I really like the looks of the Panasonic Lumix S1H, which actually costs less than the Blackmagic Design and has 4:2:2 video. I have quite a few with bad VS that I hope to get to sooner than later.

          One last question I have not determined the definite answer for. Should camphor be applied to films before long term storage or right before projecting? Someone I was speaking with today seemed to hold the opinion that making film more supple or re-plasticizing in any form shaves off life from the film. So it's best to use a product like Vitafilm only when necessary like right before projection. I'm not sure how accurate that statement is. Others have spoke their opinion to me that film with low moisture content can be more susceptible to brittleness at low temperature, so you want to make film more supple before freezing to avoid damage. I have the option of letting tabs evaporate on my entire collection before shelving them away. My opinion may change based on what I discover.
          Last edited by Ben Klesc; July 14, 2021, 02:02 PM.


          • #6
            I have my movies stored in a metal film box dating from the 1940's. A Brumberger box as they are known (see photo below). The films themselves (2007-2021) are in cardboard boxes with molecular sieves. I've treated the films with Filmguard. This product both cleans, and lubricates the film. I've projected these movies countless times with no signs of degrading. The Brumberger box also has several holes for ventilation. The bedroom they are in is climate controlled much of the year. A/C in the Summer and normal heat in the Winter. For me this works since I like to project these movies from time to time, and to share with family. In your situation, with much older films, I see the need to preserve them the best you can. But don't be too afraid to view them projected from time to time. Good luck with your preservation!

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            • #7
              So I gave the project some more thought, and contacted Will Stewart at Vitafilm. I found what camphor and products like Vitafilm and Film Renew essentially do is help aid in "renewing" film when you are about to project it. Soaking film in anything and then sealing and freezing is a seriously bad idea. The goal should be to get as dry as possible. So I've decided I won't be using that product until I'm ready to start projecting the decaying film. HOWEVER see Will's response in next post...

              Here is a forum member that had this very issue and don't really want to risk soaking film in anything until later. I may not not want to go through the hassle but it's good to know that Vitafilm does not shorten life of any film. Plus half my reels are painted and I bet the paint would melt off with solvent and make a mess.


              Here is a great resource I just found from Association Of Moving Image Archivists and Institute of Museum and Library Services (IMLS). It shows great color charts to visualize what happens when acetate film decays. It discuses acidity changes with temperature, color graphs showcasing recommended storage conditions of various analog medium. Reaching temperature equilibrium before cold storage, the measured humidity difference between taped/sealed and unsealed cans and why that is important. Recommends using moisture proof bags.


              They seem to suggest that cold storage does a better job at pausing vinegar syndrome than molecular sieves and costs a lot less as well. They recommend investing in moisture proof or moisture barrier bags like Dry-Packs instead. However I put my temp gauge in the freezer and it measured 40% humidity which isn't bad. Biggest thing is making sure frost doesn't get to the film.

              "Neither vented enclosures or use of adsorbents is a response to control acetate decay. Both alternatives help but don’t stabilize decaying material. In cold storage both have benefits in comparison with the effect of temperature at stopping VS in its tracks."

              "After 15 years, the acidity change of acetate film is 20 times greater at room temperature than at freezing temps."

              For film that is frequently taken in and out of storage and sees frequent use, freezing would be very impractical and constantly freezing and thawing may very well make matters worse. A fridge would be the second best option for films which have not already seen decay. They seem to recommend freezing for film already smelling or extended long term storage.

              Thanks for all the luck Shane, I'll need it! In my scenario my collection is starting to smell up the basement. Hopefully this will buy up much needed time while I build the setup. The goal is to finish the studio build in 5 years and I believe that is doable taking into cost consideration. Getting into the hobby of shooting with new film and projecting also sounds like a grand time.
              Last edited by Ben Klesc; July 15, 2021, 02:42 PM.


              • #8
                Will the maker of Vitafilm generously replied back today and gave advice for my project and the forum.

                "I believe your friend may be thinking of Film Guard. It leaves a thin coat of oil on the film to hide base side scratches when projected. Some people apply it just before projecting a worn print. Vitafilm is completely different. It absolutely does not shorten the life of the film, quite the contrary. It rejuvenates the film, helping it return to its original pliability and dimensions. Using it before placing your film in a deep freeze condition is a good idea. Just be sure that the Vitafilm has completely dried before freezing."

                That's very interesting to note. I still may hold off just because it's sort of a hassle and perhaps unnecessary, and I still run the risk of it not drying completely before I put it into a deep freeze and that would be a worst case scenario. That's how you run into big issues. If I want to wait it out for another month though and take my time it may be worth it. I might have to transfer all of my film over to unpainted reels. I'm considering my options over the next week.


                • #9
                  Filmguard is designed for films that are not in cold storage. Using it on newer films that haven't started to degrade makes sense. In my case, since I use my films, Filmguard works well in keeping them pliable, and from drying out. Dry film does not project as well. In your case sealing lubricated film in the freezer could be an issue. We would need to hear from the person who designed and who sells Filmguard. I think he's a member here by the name of Bill?


                  • #10
                    Very good reading, Ben. I've done this sort of thing for years, and it does work quite well. Just be sure that no moisture, whatsoever, gets to the film, as, if so, it will be all for naught.


                    • #11
                      I decided I would reach out to Reto Kromer over at AV Preservation, along with Tommy Achenbach at Colorlab. Currently waiting for a response but I feel like I've made up my mind at this point.

                      Products like Vitafilm do not reverse or prevent vinegar syndrome. They do mask the smell, and they make film less brittle which has shrunk, but they do nothing as far as extending longevity of decay. Soaking a warped film in a bucket of VitaFilm or FilmRenew will also make you re-do all splices. Plus the fact I will be freezing straight afterwords makes less sense.

                      If I really want to do any treatment beforehand it would be a lot less hazardous and make much less of a mess and less expensive just letting camphor tabs evaporate into the film. I may do nothing to be honest because freezing is the most important part. It sort of sounds like the film becomes addicted to using product. The more you use lubricants and re-plasticizers the more you have to use it. It "speeds up the process of degradation."


                      "I used Vitafilm on a VS print of a B+W Gunsmoke episode. I soaked the film for about a month and cleaned it carefully after removing from the soaking. The smell was much better. However, six months later I had to dispose of the print as it had warped beyond anything close to being able to be projected."


                      • #12
                        Originally posted by Ben Klesc View Post
                        I decided I would reach out to Reto Kromer over at AV Preservation, along with Tommy Achenbach at Colorlab. Currently waiting for a response but I feel like I've made up my mind at this point.
                        I knew the best condition would be cold and dry which represented by freezer unit if we want to preserve our films as long as possible. But not everyone has it

                        Ben.. can you also ask them (or may be from other source too) what will be the impact to estate film base for hot and dry as well as cold and humid climate.

                        Definitely hot and humid is the worst place as it happens in my tropical country, Indonesia.



                        • #13
                          Originally posted by Winbert Hutahaean View Post
                          Ben.. can you also ask them (or may be from other source too) what will be the impact to estate film base for hot and dry as well as cold and humid climate.
                          They never replied back. However this is a good film calculator that lets you put your temps and humidity level and estimates how long your acetates will last in storage based on your conditions. Temperature is more important than humidity. Hot temps are the worst. Just going from room to below freezing significantly increases it's life expectancy in storage. Humidity does not affect it as much. You don't want film to become too dry either and become brittle and shrink. You don't have to worry about mold in the freezer.


                          Most film has not been kept in ideal storage conditions, so if you run into very old mags chances are it is almost at the end of its life and so freezing it should be considered very important if you want to preserve it for the next century. In my case I'm hoping to extend my collection which has already developed vs another 10-20 years. Freezing is the only method that halts deterioration and costs nothing but loss of space in your fridge, despite what other products claim to do.

                          By the way tape is much different from film. Unlike film, the life expectancy of tape cannot be extended by changing the temperature. There is no benefit to freezing tape. So I keep my tape collection at room temps and low humidity. Film has an incredible ability to outlast video. Much of the Hi8 we used for home movies in the 90's is now starting to become unplayable. Especially dreaded Sony.
                          Last edited by Ben Klesc; July 28, 2021, 09:11 PM.


                          • #14
                            Found some more great literature from Northeast Document Conservation Center. I was wondering about polyester.

                            "For all film bases (nitrate, acetate, and polyester), frozen temperatures with an RH of 30-50% extends the useful life of film. A low-cost alternative to offisite cold storage are off-the-shelf frost-free freezers or refrigerator, but careful packaging is necessary to protect motion picture films from humidity."

                            The Association of Moving Image Archivists Storage Guide


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                            • #15
                              I went and had a go at it. I used mylar bags since ziplock tends to not keep its seal. Who needs to eat? 😊

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