Freezing negatives

We have recently purchased a freezer for cold storage of negatives,
and are waiting for freezer storage bags from Conservation
Resources.  Our first collection for the freezer is made up of
nitrate and acetate negatives.  I have researched procedures for
freezing the negatives and have a question.  According to Paul
Messier (Preserving your Collection of Film-Based Photographic
Negatives, 1993, available in CoOL
<URL:http://palimpsest.stanford.edu/byauth/messier/negrmcc.html>),
for example, the nitrate and acetate negatives should be stored in
different freezer bags so that deterioration of one does not affect
the other.  However, once something is in the freezer, the
deterioration will obviously slow down considerably.  With that in
mind, just how important is it to separate the nitrate and acetate
into separate freezer storage bags?

A related question:  Is it still the procedure to remove severely
deteriorated negatives from the collection before freezing?  Would
this apply to diacetate negatives that have begun to shrink and
buckle to various degrees. And if so, why? Wouldn't freezing inhibit
the deterioration?

Michele Ostrow
Archivist
Texas State Library and Archives Commission

                                  ***
                  Conservation DistList Instance 13:26
                Distributed: Wednesday, October 20, 1999
                       Message Id: cdl-13-26-010
                                  ***