Film-Tech Forum ARCHIVE: John Pytlak: Kodak discovery on VS?

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Posted by Jeff Taylor (Member # 443) on 08-28-2001, 08:05 AM:

In a current thread on 16mmfilms.com a fellow quoted an article in the Australian Amateur Cine Society journal from 1994 in which Kodak supposedly was experimenting successfully with zeolite, a form of sodium aluminosilicate, packaged in semi-permiable poly wraps, to halt / arrest vinegar syndrom. It went on to say that the Rochester labs were experimenting with 10 old films including an original "Broadway Melody of 1936" negative. Is there any truth to this, or was this perhaps research which resulted in the molecular sieves? Appreciate any info.

Posted by John Pytlak (Member # 331) on 08-28-2001, 01:14 PM:

Kodak's patented "Molecular Sieves" adsorb the moisture and acids that are associated with "vinegar syndrome", greatly reducing the rate of degradation. I presented the technical paper to the SMPTE on November 2, 1993. There is lots of information on the Kodak and FPC website:
http://www.kodak.com/country/US/en/motion/support/technical/molecular.shtml
http://www.kodak.com/country/US/en/motion/hse/mole.shtml
http://www.kodak.com/country/US/en/motion/support/technical/vinegar.shtml
http://www.kodak.com/country/US/en/motion/hse/safeHandle.shtml
http://www.fpcfilm.com/US/en/motion/FPC/fpc/mpa_prod.html
http://www.fpcfilm.com/US/en/motion/FPC/fpc/mole.html

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Leo Enticknap (Member # 534) on 08-30-2001, 06:23 AM:

The original 'Broadway Melody of 1936' negative would almost certainly have been nitrate, which is not affected by vinegar syndrome (because the cellulose is dissolved in nitric, rather than acetic acid). Unless the surviving element is a diacetate intermediate, I can't see how any treatment designed to address vinegar syndrome would help it.

Fine-grain interpositives, which were contact printed onto acetate butyrate or acetate propionate stock direct from the camera negative, were sometimes made as so-called 'insurance prints' due to the reduced risk from fire. Some insurance companies insisted that these be struck and stored in a security vault as a condition of underwriting a production. Acetate (safety) film was not used on any significant scale by the movie industry until the launch of 'high-acetyl' cellulose triacetate in 1948 because it was far more brittle, fragile and prone to short-term shrinkage than nitrate was. However, it was OK for just printing once or twice, hence its use for insurance safety copies. In fact, the term 'insurance PRINT' is quite misleading, because they are in fact many generations closer to the original negative than any release print would be.

Quite a few films have been saved that way. For example, when a nitrate vault burnt down at a small lab in South London specialising in archival work in 1992, the camera negatives of several well-known Ealing comedies, which were being printed up for a national re-release, were lost. New preservation masters were made from the insurance prints, which the National Film and Television Archive had kept in a separate location.

Posted by Jeff Taylor (Member # 443) on 08-30-2001, 09:23 AM:

Good point, Leo. I was aware that acetic acid was an "acetate" issue and did not apply to nitrate, so the mention of "Broadway Melody" did ring a bell in my head, but I did not know about the insurance negs. My question was really whether this 1994 article referred to research leading up to the molecular sieves, or whether there was some other "wonder cure" that Kodak was playing with. From John's response I gather it's the sieves, which in my case aren't too practical for some 300 odd features stored on open shelves!

Posted by Mark Gulbrandsen (Member # 72) on 08-30-2001, 12:56 PM:

Hi Leo,
I'm curious what Ealing negatives were lost in the fire. Thats pretty sad but it is dangerous stuff and it has happened before.
Also, does anyone know who distributes the Ealing films here in the States?
Mark @ GTS

Posted by Leo Enticknap (Member # 534) on 08-31-2001, 02:50 AM:

The o-negs of 'Whisky Galore' and 'Kind Hearts and Coronets' went up in the Hendersons fire. There's a mention of it in Penelope Houston's book on film archives, 'Keepers of the Frame' (London, BFI, 1984).

The worldwide rights to all the Ealing output from when Gaumont-British sold the studio in 1938 to when the BBC bought it in 1956 are now owned by Canal Plus, a French broadcaster. Someone told me that they do have a rep in New York but I couldn't give you any contact info - sorry. Sadly they haven't put any money into providing decent new prints recently and so apart from the occasional screening of National Film Archive prints in London, the only prints you get to see here are worn-out 1970s copies.

Posted by John Walsh (Member # 168) on 08-31-2001, 08:43 AM:

That's too bad about Whisky Galore; it's one of my fav's. There's just so much film to save(and store), sometimes I'm surprised as much has survived.

Posted by Bernard Tonks (Member # 809) on 09-02-2001, 04:29 PM:

Many years ago I did a showing of Ben Travers “Rookery Nook” which was thought to be forever lost as the original negatives were destroyed in a vault flood. A nitrate copy was found in the basement of a derelict cinema and the film was completely restored by the BFI.

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Posted by John Pytlak (Member # 331) on 09-04-2001, 02:26 PM:

Leo said: "The original 'Broadway Melody of 1936' negative would almost certainly have been nitrate, which is not affected by vinegar syndrome (because the cellulose is dissolved in nitric, rather than acetic acid). Unless the surviving element is a diacetate intermediate, I can't see how any treatment designed to address vinegar syndrome would help it."

Although cellulose nitrate and cellulose triacetate are different polymers, the hydrolysis reaction that causes degradation of the base is similar, releasing acid vapors and moisture. In a sealed container, Molecular Sieves adsorb the moisture and acids released, and so will slow the degradation of either type of film:
http://www.kodak.com/country/US/en/motion/support/technical/molecular.shtml
http://www.kodak.com/country/US/en/motion/support/technical/vinegar.shtml
http://www.kodak.com/country/US/en/motion/hse/safeHandle.shtml
http://www.kodak.com/country/US/en/motion/hse/mole.shtml