Storing cellulose nitrate artifacts

Lisa Ann Bengston <lbengston<-a t->royalbcmuseum< . >bc< . >ca> writes

>We are considering cold storage for the cellulose nitrate artifacts
>in our History collection.  Those cellulose nitrate artifacts that
>are visibly deteriorated will be rehoused and sent to our offsite
>cold storage facility immediately.  The question is what to do with
>those cellulose nitrate artifacts that appear to be stable at this
>time. ...

Many movie film and photographic archives tend to recognise the fire
risk CN film poses to the rest of the collection, and store CN
material, good or bad, in a cold storage facility well away from
other collections.

Museums with large collections of objects often have many CN or part
CN objects which have been poorly described as 'plastic', 'horn',
'tortoishell', 'cellulose acetate' or one of the other names for
cellulose nitrate; collodion, celluloid, from which many common
objects are made, not to mention something like gun cotton, which
naturally arouses suspicion.

Because of this confusion, the failure to identify acid gas attack
on nearby objects, and few fires identified as of CN origin, it is
often hard for conservators to interest museum management in the
risk management aspect of storing this material which, in furious
combustion, generates its own oxygen along with highly corrosive
gases.

Strictly speaking, for this reason alone, all CN material should be
isolated from the rest of a collection.  A-D strips were designed
for quantifying the rate of cellulose acetate decay, and I am
unaware of any simple and practical method of doing this with
nitrate.

This is all complicated by the fact that thin nitrate, without bulk,
tends to last quite well, and important objects are made from it. We
can't 'copy and burn' as was done with much CN movie film when the
panic set in.

I think Lisa's proposition to transfer deteriorating material to
cold storage and retain CN materials with the collection is sensible
but inadequate.  I have had the same problem in the past unresolved.
Yvonne Shashoua has shown that bulky plastics experience damaging
thermal stress when moving into and out of cold storage.

James Elwing
Archival conservator (NSW, Australia)
Elwing and Gurney Archival


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                  Conservation DistList Instance 27:40
                  Distributed: Friday, April 18, 2014
                       Message Id: cdl-27-40-003
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