To my knowledge it is - for most objects of not natural history museums -
not the absolute humidity level, but the changes that hurts. E.g. pianos
with wooden constructions survive a wide range of humidity, but crack soon,
when the humidity changes within a day to often. Subtle changes of humidity
(5 % per half day) and a wide range of absolute humidity (30 to 75 %) is
acceptable to most "normal" museum objects like paintings, machinery,
pianos, but of course, not to paperworks, special biological tissues and
plants.

Peter, the Austrian Rebernik

-----------------------------------------------------
"Advice is like snow; the softer it falls, the longer it dwells
upon, and the deeper it sinks into the mind."
--Samuel Coleridge
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-----Ursprüngliche Nachricht-----
Von: Vallin, Amy <[log in to unmask]>
Newsgroups: bit.listserv.museum-l
An: [log in to unmask] <[log in to unmask]>
Datum: Freitag, 10. September 1999 18:25
Betreff: Re: Humidity in Museums


>To my knowledge acceptable humidity level for artifacts is 40% humidity.
At
>the Science Center we try very hard to keep our collection storage area at
a
>low humidity level.  It is not always easy, we are in the Ohio River Valley
>and humidity levels are high.  The Kentucky Historical Society just opened
a
>new facility and they might be able to give you more information.
>
>Amy Vallin
>Collections Research Coordinator
>Louisville Science Center
>727 W Main St, Louisville, KY 40202
>502-561-6100 ext. 6568
>
>> ----------
>> From:         Chris Woodson
>> Reply To:     Museum discussion list
>> Sent:         Friday, September 10, 1999 9:17 AM
>> To:   [log in to unmask]
>> Subject:      Humidity in Museums
>>
>> Hi,
>> I was wondering if anyone out there has experience or knowledge of
>> humidity
>> inside museums.  I am currently involved in compiling data regarding the
>> humidity levels in our exhibit hall.  We have hygrometers strategically
>> placed throughout the building and I have been developing a spreadsheet
>> with
>> the accumulated data.  What I am wondering is, what humidity level is
>> considered acceptable in a museum environment?
>>
>> Thanks,
>> Chris Woodson
>> Roanoke Island Festival Park
>> Manteo, NC
>>
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