Relative humidity specification

The target humidity parameters for archives and rare book housing is 50%
RH with discrepancy of 2.5 percentage points. Current humidity in this
library is 27% or greater, depending on outside atmospheric conditions,
but during the winter, stays way below an acceptable reading.  Further
complications are found in the confined space of exhibit casing where
this problem is compounded.  Does anyone have any suggestions as to
raising the humidity in either instance?

Assistance greatly appreciated

Susan Alon
Rare Book Librarian
Washington University School of Medicine
St Louis

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                  Conservation DistList Instance 6:43
                Distributed: Thursday, February 4, 1993
                        Message Id: cdl-6-43-008
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