In response to Nancy Freeman's inquiry about
relative humidity. I did most of my conservation/preservation training in
the Northeast and then returned to the West. I feel that a lot of the
guidelines are written without the climate of the Western US and other dry
climates in mind. I have found that here in ALbuquerque the RH can be
between 20% to 35% in the winter, sometimes dipping down to treacherous lows
such as 12%! In the summer "mansoon" season the RH can be between 40% and
55% sometimes reaching above 60%. I would discourage the use of local
dehumidifiers and humidifiers as they are very labor intensive to keep running
and introduce the risk of fungal growth. The best guideline I have found
on this subject in from Barbara Applebaum's book entitled "Guide to
Environmental Protection of Collections" Madison, CT: Sound VIew
Press, 1991. p. 35
"A steady RH every day and night of the year at any
feasible level between about 40 and 60% would be virtually ideal for most
collections. For reasons we shall see later, this may be prohibitively
expensive and difficult to manage. A reasonable alternative that would
provide significant protections would be to provide a steady RH of about 35-40%
in the winter, a steady 60% in the summer and to reaise and lower the levels
between the two in the fall and spring, with daily fluctuations of no more than
a few percent, monthly levels that change no more tha 5% per
month."
You must read more of this section to fully
understand the context of this statement. You may consider hiring an
environmental consultant such as Ms. Applebaum or William Lull.
Jo Anne Martinez-Kilgore
Cariño Conservation of Books and Paper 1608 Los Arboles Ave. N.W. Albuquerque, New Mexico 87107 (505) 343-9172 |