Mold on musical instrument cases

Sean Harrison <seanh [at] experience__org> writes

>We have a few old musical instrument cases that show signs of mold
>outside and in.  When we see this condition we always separate the
>instrument from the case, give both a good vacuuming, and store them
>in two polyethylene bags each as a quarantine.  Our work room
>relative humidity is on average of 20%, and our store room RH is 40%
>flat; so outbreak is mitigated somewhat by this dry environment. The
>substrates are dry at this point, thus limiting another source of
>humidity.

I am seriously puzzled by the letter from Sean Harrison. I must
admit that my theoretical background is somewhat rusty, taking my
degree in microbiology back in 1980. However, looking in my text
books from then, the statement is that xerophilic fungi are never
found below a relative humidity below 56% RH. As exactly this limit
has been studied to great detail over the years I would be surprised
if this does not hold today, and it seems far away from the value of
40% RH measured in the stores. Therefore, could there be cold spots
where you keep your instruments, giving rise to a higher relative
humidity in a local area? Could there be any other factor(s) that
could increase the RH over a period of time long enough to create a
higher relative humidity, and therefore growth? I would recommend a
close examination of these questions as control through the RH is
probably the best way to inhibit future attacks.

Jens Glastrup
Senior Research Scientist
The National Museum of Denmark

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                  Conservation DistList Instance 12:83
                  Distributed: Friday, April 30, 1999
                       Message Id: cdl-12-83-007
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