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Re: Cleaning Nitrate?



At 08:47 PM 4/11/96 +0000, you wrote:
>     A client of ours has some old nitrate film and called to ask 
>about transferring it.  One of his questions was if we could sonic 
>clean it, and I'm personally not sure.  We have a CF200 with 
>Trichlor, still, and my initial feeling is that it would not be a 
>good idea.  Specifically the heated drying tower is a worry point.

Robert,

I work for the Library of Congress, Motion Picture Preservation Lab in
Dayton, Ohio and we clean nitrate in 1.1.1 tri and perchlorethelene on a
regular basis in a Lipsner Smith ultrasonic cleaner (model # escapes me at
the moment).  However, our machines do not have a drying-tower, as you
mentioned, and I cannot comment on that portion of the process.  

>     I really don't know what shape his film is in, but I tend to 
>think having the film "rejuvenated" might be a better option than a 
>sonic cleaning.
>     So, does anyone know the proper way to clean nitrate film?  If a 
>rejuvenation bath is a good idea, can anyone recommend a good 
>facility?  I have a feeling there's a fair amount of film involved, 
>perhaps 10,000 feet of 35mm.

I would avoid rejuvenation as it might accelerate the decomposition process
of the nitrate originals.  The best bet would be to print the originals over
to safety, and then transfer the resulting materials (always hanging-on to
the original nitrate until the bitter end!) 

I would suggest you contact the MPPL Lab Supervisor, Kenneth Weissman at
(513) 258-7220 or kweissma at loc.gov to discuss the ins and outs of cleaning
nitrate.  Tell him I sent you.

>     Finally, can someone provide a timeframe for the replacement of 
>nitrate by safety film?  My memory's vague on that (I'm not _that_ 
>old!) but I seem to remember the mid 20's though an associate here 
>thought it happened in the late 30's.
>     Thanks for your help!
>
>Robert

Eastman Kodak phased-out nitrate in 1951 (or so) and committed to
tri-acetate base stock production;  however,  production of safety-base
filmstocks began as early as 1909.  See, "History of Professional Black and
White Motion Picture Film", C.E. Kenneth Mees, SMPTE, October 1954, for more
details.

S. Frank Wylie
Timer, Library of Congress, MPPL
Kinoville - http://www.infinet.com/~frank/frank.html