The final word about the longevity of film?

Discussion in '35mm Cameras' started by Sabineellen, Jul 1, 2004.

  1. Sabineellen

    Sabineellen Guest

    http://www.pbs.org/newshour/bb/media/jan-june04/bettmann_06-10.html

    According to this interesting article from a real case report about a most
    valuable photographic archive (Bettmann's 11 million images of the 20th
    century, owned by Bill Gates' Corbis), it seems that if stored in room
    temperature (Broadway, NYC) film disintegrates in not too long (a few decades,
    some older ones already did, though modern film is implied to be better) but if
    frozen below zero it lasts "thousands of years; not hundreds, thousands".

    "Wow".

    Once i get my 4870 I'll start scanning films at its maximum and just use the
    scans, then get a good quality tightly-sealed tupperware-like container and
    small resealable freezer bags, individually put each set of film negatives in a
    small freezer bag, stick an identifying label on it from the digital database
    on my computer, and stack em all in the container.

    This will hopefully protect it from moisture and freezeburns in case that'd be
    a problem. Something generic like this would probably do perfectly

    http://www.ziploc.com/freezer.asp
    http://www.ziploc.com/container.asp

    Given that almost everyone has access to a freezer already to store their food
    and that the cost of ziploc is negligible, i find this is phenomenal.
     
    Sabineellen, Jul 1, 2004
    #1
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  2. Sabineellen

    Jeremy Guest

    Ziploc? Have you checked if the resin used in those bags is of archival
    quality? If the plastic leaches fumes they could attack your film. Ziploc
    bags have not been advertised as archival storage bags.

    Also you must be sure not to let the film be affected by humidity or
    condensation. I've heard of special foil-lined freezer bags for prints, but
    I can't remember where I saw them. Maybe on the Kodak web site?
     
    Jeremy, Jul 1, 2004
    #2
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  3. The Smithsonian stores original documents like the Constitution and the
    Declaration of Independence under dry nitrogen in air tight cases with a
    slight positive pressure from a nitrogen bottle. One bottle lasts years and
    the nitrogen atmosphere prevents the paper from aging as it would in air
    that is about 21% oxygen. I wonder if this wouldn't be better for long term
    storage of negatives too. It would be cheaper, since it takes continuous
    power to keep a freezer going, and also if there is a power failure, the
    freezer would gradually come up to room temperature.
     
    William Graham, Jul 1, 2004
    #3
  4. Sabineellen

    Sabineellen Guest

    http://palimpsest.stanford.edu/byauth/messier/negrmcc.html

    Good article...

    "Conservators of Fine Arts and Material Culture
    Rocky Mountain Conservation Center
    Preserving Your Collection of Film-Based Photographic Negatives
    Paul Messier
    Conservator of Photographic Materials and Works of Art on Paper
    ABSTRACT

    The problem presented in the title of this paper can be addressed simply by two
    words: cold storage. Recent research indicates that all cellulose-based film,
    whether it's a cellulose nitrate negative from the 1890's or a cellulose
    triacetate color transparency from the 1990's, share very similar deterioration
    mechanisms that are temperature and humidity dependent. On balance, relative
    humidity has been shown to be a less serious concern at low temperatures. What
    this means for a collections manager is that long term preservation of a
    collection of film-based negatives is as affordable as a frost-free freezer. "
     
    Sabineellen, Jul 1, 2004
    #4
  5. freezer. "

    Yes.....While the article didn't specifically say that dry nitrogen storage
    had been tried and failed, I presume that they had ascertained that freezing
    is the best method....My problem with it (the article) is that they didn't
    specifically say exactly what the chemical deterioration process was. That
    is, they didn't give the chemical breakdown process formulas, so I don't
    know whether the presence of oxygen has anything to do with it. IOW, it
    still didn't answer my question.
     
    William Graham, Jul 1, 2004
    #5
  6. freezer. "

    Yes.....While the article didn't specifically say that dry nitrogen storage
    had been tried and failed, I presume that they had ascertained that freezing
    is the best method....My problem with it (the article) is that they didn't
    specifically say exactly what the chemical deterioration process was. That
    is, they didn't give the chemical breakdown process formulas, so I don't
    know whether the presence of oxygen has anything to do with it. IOW, it
    still didn't answer my question.
     
    William Graham, Jul 1, 2004
    #6
  7. Just a couple of comments:

    First is the Tupperware and Ziploc issue. Plastics in general have some
    bad effects on long term (even short term) storage of many materials
    including photographic. Some plastics are much better than others. I
    suggest using true archival materials for storage. There are sources for
    such materials like Light Impressions.

    Second reduced temperature and light (along with moisture) has always
    been the bases for archival storage.

    Third, well made archival prints tend to last much longer than
    negative/transparent materials both from the perspective of the image itself
    and the material supporting it.

    Last, low moisture is a plus for long term storage of most photographic
    materials. Most such materials benefit from low moisture and are not
    subject to freezer burn like that rump roast stored in the back of your
    freezer.
     
    Joseph Meehan, Jul 1, 2004
    #7
  8. Please read these remarks as being from a chemist (OK, ex-chemist) with
    an interest in the technicalities of photography, rather than from an
    expert conservator. For real expertise, see the works of the Wilhelm
    Institute and others.

    There are two quite different mechanism for degradation of things like
    films. One is thermal, the other photochemical oxidation.

    Thermal degradation will go on in the dark, and roughly doubles in rate
    for every 10 degrees temperature rise. It may or may not be increased by
    the presence of water, but for degradation of film base it almost
    certainly will, as it is very probably a hydrolysis of the ester from
    which it is made. This produces acid, which will accelerate the
    reaction, sometimes to catastrophic rates.

    Photochemical oxidation requires light and oxygen. It will generally
    increase in rate at higher temperatures, but normally not to the same
    degree. It is particularly damaging to colour dyes; probably less so to
    the film base.

    To protect film properly, it needs to be covered from both dangers. Thus
    - dark, dry and cool. Lack of oxygen is a bonus, but probably not nearly
    as important as lack of light.

    The position of paper documents with ink or pencil writing is a little
    different, as the thermal degradation of the paper base is not a major
    issue, and photochemical oxidation is probably the main threat. Do bear
    in mind thought that photographic paper is often resin coated and (if
    colour) contains dyes, and must be treated similarly to film.
     
    David Littlewood, Jul 1, 2004
    #8
  9. The chemical degradation of acetate film base is described in the
    following document:

    http://www.rit.edu/~661www1/sub_pages/acetguid.pdf

    In short, the material breaks down under the influence of heat, acids,
    and moisture, releasing acetyl groups. Oxygen is not required for the
    reactions. The recommendations are to keep film in low temperature, low
    humidity storage. Once acid is allowed to build up beyond a certain
    point, deterioration accelerates very quickly.

    (There are also some short discussions of nitrate and polyester film
    base deterioration.)

    Some quotes about acetate film:

    ===================================
    "Many archivists are familiar with the slow chemical deterioration of
    cellulose nitrate film, but they have assumed that cellulose acetate (so
    called "safety" film) is something entirely different. It turns out
    that cellulose nitrate and cellulose acetate both share a built-in
    propensity to degrade; both these plastic materials are modified forms
    of cellulose, and both have a regrettable tendency to become
    "un-modified" by the same kinds of chemical pathways."

    "... Detachment of acetyl groups also can occur in the presence of
    moisture, heat, and acids ... free acetic acid is liberated."

    "The acetic acid is released inside the plastic, but it gradually
    diffuses to the surface, causing a familiar sharp odor - the odor of
    vinegar. ... in advanced stages of deterioration, there can be nine
    teaspoonfuls or more of vinegar for every four feet of 35mm movie film."
    ==================================
     
    James Robinson, Jul 1, 2004
    #9
  10. Sabineellen

    Alan Browne Guest

    Except that
    1) Building a hermetically sealed chamber is not as easy as you
    might think.
    2) You *do* want to access the photos, not just look at them
    behind glass
    3) If so, you need to have a purge protocol too every time you
    re-seal ... lot's of N2 needed.


    ....yes it works, but not very convenient to access the photos.
    Much easier to just store at cold temp. Power failures don't
    last long enough for a deep freeze to warm up much (if you leave
    it alone).
     
    Alan Browne, Jul 1, 2004
    #10
  11. Sabineellen

    Alan Browne Guest

    I don't know how many times I've pointed this out ... film/paper
    are already "frozen" (so to speak) at room temperature. Putting
    them in a freezer merely lowers their temperature further.
     
    Alan Browne, Jul 1, 2004
    #11
  12. Sabineellen

    Sander Vesik Guest

    Well, in case youhaven't been paying attention, so does meat. Freezing stops
    or incredibly slows down most chemical processes. Case in point - meat,
    particularily that of permanently frozen mammoths.
    There is a problem with this if you occasionaly melt it. freeze / unfreeze cycles
    are not so good.
     
    Sander Vesik, Jul 1, 2004
    #12
  13. Alan, ever heard of the term "emulsion"?
     
    David Littlewood, Jul 1, 2004
    #13
  14. Sabineellen

    Alan Browne Guest

    The air you breathe is mostly N2 (about 70%). So when you pop
    the lid it will mix freely.

    Bottles of N2 are of course pressurized well above 1 atmosphere.

    To 'purge' a volume, N2 is let into the volume at one end, and an
    exhaust valve lets out the other gasses (and much of the N2).
    Close the exhaust and inlet valves. Let some time pass to
    absorb surface gas (incl. moisture) and then vent again.
    Depending on how anal you are you can purge several times but 2
    or 3 is probably adequate for the cause at hand. Keeping the
    hermetically sealed volume at some nominal pressure above 1
    atmos. is of course desired.

    Then cool the whole damned thing to -10 or -20C or so. Note that
    while cooling, the pressure inside will drop, so compute (Boyles
    Law or is it Charles?) the drop in pressure and take that into
    consideration when you pressurize the volume to arrive at a final
    pressure that is at least 20% higher than ambient.

    Real easy, but not very convenient.

    Cheers,
    Alan
     
    Alan Browne, Jul 1, 2004
    #14
  15. It's lighter - not by much. N2 is 28g per mole, O2 32g per mole and the
    mixture (air) approximately 28.8g per mole. Volume of 1 mole is BTW 22.4
    litres, so if you want absolute densities work it out yourself.
    Other inert gases would cost many times as much. There are efficient
    purging regimes which would be fine here - N2 is cheap.

    David
     
    David Littlewood, Jul 1, 2004
    #15
  16. Sabineellen

    Nick Zentena Guest

    Pop keg. AKA cornelius keg. Relatively cheap used. Not that expensive new.
    Negatives of almost any size would fit. Quite a few 35mm negatives would fit.

    Easy enough. Just release the pressure and pop the lid.
    Is N2 heavier or lighter then air? If it's heavier then the N2 isn't
    going anyplace when you pop the lid. When you pressurize the tank you'd vent
    the top. What comes out would be mostly the lighter air. Do the vent step
    several times and the tank would be pretty pure N2. If it's lighter then
    it's harder. I wonder if you could draw from the bottom of the keg? OTOH
    just using a different inert gas that's heavier then air would solve the
    problem.


    Nick
     
    Nick Zentena, Jul 1, 2004
    #16
  17. Though to be fair that is in large part due to the effect of ice
    crystals rupturing the sell walls of biological material if the freezing
    process is not very carefully controlled.
     
    David Littlewood, Jul 1, 2004
    #17
  18. Sabineellen

    Nick Zentena Guest

    That's standard method for purging kegs. It's easier with CO2 since CO2 is
    heavier then air. The air gets pushed into the top of the keg near the
    pressure relief valve.

    The regulator would handle keeping the pressure up. A person could setup a
    chest freezer with a manifold for supplying the nitrogen. 1 psi is pretty
    low but if a higher pressure level would be okay then it's a setup that
    could be rigged using off the shelf parts.

    Well not easy if the negative you want is buried at the bottom of the keg.
    Not great if you need constant access to the negatives but should be fine
    for long term storage.

    Nick
     
    Nick Zentena, Jul 1, 2004
    #18
  19. Sabineellen

    Tony Spadaro Guest

    As one who has opened boxes of unexposed film from sealed packages that were
    stored in a freezer and found the film wet - I can tell you freezing is not
    the safest way to store anything that must stay dry.
     
    Tony Spadaro, Jul 1, 2004
    #19
  20. Sabineellen

    Alan Browne Guest

     
    Alan Browne, Jul 1, 2004
    #20
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