Salvaging water-damaged photographs in enclosures

I am updating our library's collections emergency manual, and I have
a few questions about salvaging photographic materials.
Specifically, I'm curious about salvaging techniques for
water-damaged photographic materials that are in individual
enclosures (including glassine, archival paper, polyester, etc.)

The literature I've come across advocates freezing most types of
photographic formats whenever air-drying is not feasible. However, I
have yet to find anything that explicitly mentions whether freezing
photographs or negatives in their enclosures is likely to cause
additional damage.

Granted, whether photographic materials can be treated successfully
after freezing depends on a number of factors, like format and
condition. But, all things being equal, is a wet photograph that's
frozen inside an enclosure worse off than a photograph that's taken
out of the enclosure and then frozen?

What about freezing water-damaged framed and matted photographs?
Most literature on the subject recommends that photos always be
removed from mats and frames prior to freezing.  But if the photo
isn't touching the glass (or plexiglas, as the case may be), is it
always necessary to take the time to remove the photo from the frame
before freezing? Or could this be done after the collection has been
frozen, when the conservators can devote more time to individual
items?

I'd be interested to hear from anyone who has dealt with this issue
in the past, particularly anyone with experience (either positive or
negative) treating photographic materials that have been frozen in
their enclosures.

I'd also be curious to hear from any of you with thoughts about
washing flood-damaged photographic collections.  If time and
resources allow, is it more beneficial to wash wet/muddy photographs
before freezing?  Are there real consequences for waiting to wash
the items until after they've been frozen?

Mary E. Miller
Preservation Librarian
Preservation Department
Stanford University Libraries
1450 Page Mill Road Room 132
Palo Alto, California 94304
650-721-1612
Fax: 650-725-0547
Mobile: 650-644-7869


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                  Conservation DistList Instance 23:30
                Distributed: Tuesday, February 16, 2010
                       Message Id: cdl-23-30-015
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