Using vesicular/diazo film for service copies

In response to the inquiry from Elayne Bond at Northwestern University
Library regarding the use of vesicular or diazo use copies:  at the
Center for Archival Collections, Bowling Green State University, we have
all three types of film in our collection. However, we mainly produce
vesicular copies for our patrons.  Vesicular, while not considered
archival, will stand up to much more use (and abuse).  It does not
scratch or break as easily as silver halide because the emulsion is
sandwiched between the polyester, not exposed as is the silver. We feel
that the vesicular outlives the silver in its usefulness, and even if it
must be replaced (as, you have seen, the well-used silver copies will)
it saves money in the long run.  We only produce silver copies when we
feel it is necessary.  I would encourage you to stay away from diazo.
It will begin to self-destruct in a decade or so, and the use copies are
usually negative, which many patrons dislike. We are in the process of
replacing all our diazo copies, most of which are less than twenty years
old, as they are experiencing some nasty "vinegar syndrome".

Susan Hughes
Micrographics Specialist
Center for Archival Collections
Bowling Green State University
Bowling Green, Ohio

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                  Conservation DistList Instance 7:88
                   Distributed: Monday, June 6, 1994
                        Message Id: cdl-7-88-005
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