In article <[log in to unmask]>,
Jane Glaser  <[log in to unmask]> wrote:
>I realize the message from CAL was an important one, but the format
>of sending the message was garbling! Half of it was missing. Please
>repeat.  Thanks so much.
 
The following is a re-posting of J. Druzik's article, with the line
lengths (some were over 600 chars long) shortened to less than 80 characters
so that long lines don't get truncated by some of the mail readers. The
original typos (Druzik's ? or SI's?) were not tampered with. Peter Rauch
 
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Date: Thu, 22 Sep 1994 07:49:47 -0800
From: Jim Druzik <[log in to unmask]>
Subject: Smithsonian Press Release
 
The following press release was recently issued by the Conservation
Analytical Laboratory of the Smithsonian Institution.  The research
upon which the press release has been predicated has evolved over a
number of years and has been presented at various meetings of the
Materials Research Society, American Chemical Society and the IIC.
Therefore, to many of us the research is not new, nor is it technically
unsound.  My question to the Discussion List pivots on how it has been
extended to collections and presented in the following release and
whether or not this makes the job of the institutional and private
conservator or museum administrator easier or more difficult.  It seems
there are a number of credibility issues involved especially for
current or planned building programs.  It also seems to some that the
press release can easily be responded too in a rather volatile manner.
What do you think?
 
James Druzik
Conservation Scientist
The Getty Conservation Institute
 
WORK OF SMITHSONIAN SCIENTISTS REVISES GUIDELINES FOR CLIMATE CONTROL
IN MUSEUMS AND ARCHIVES
 
Smithsonian researchers have found that museum objects can safely
tolerate a wider range of temperature and relative humidity than
previously believed.  This new insight could save museums millions of
dollars in construction and energy costs to maintain environmental
conditions once considered essential for the preservation of
artifacts.
 
The Smithsonian researchers, materials sciewntists at the institution's
Conservation Analytical Laboratory in Suitland, Md., announced their
conclusion about climate control in museums when results of some of
their individual research projects were reported at a meeting this week
of the American Chemical Society in Washington, D.C.
 
The CAL Scientists -- Marion Mecklenburg, Charles Tumosa, David
Earhardt and Mark McCormick-Goodhart -- reached their conclusion in the
past year, during a series of investigations of the chemical, physical
and mechanical properties of materials common to a wide variety of
museum objects: anything fron natural history specimens to
archaeological artifacts, for example, 19rh-century landscape
paintings, and photographic prints and film.
 
"As scientists, wo don't work from the idea that each object in a
museum is unique," Mecklenberg said, "Rather, we start by looking at
the whole picture -- examining and understanding all the materials
found in the vast majority of museum objects."
 
Previously, "ideal" environmental conditions for museums and aechives
had been set at 21 degrees Celsius (70 degrees Fahrenheit) with 50%
relative humidity.  Now, Mecklenberg says, there can be as much as 15%
fluctuation in ralative humidity and as much as 10 degrees Celsius
difference in temperature.
 
Through informal discussion of their work, the researchers say, can the
understanding of materials such as wood, cellulose, various polymer
coatings, fibers, minerals, pigments and the like share an overlapping
range of tolerance to temperature and relative humidity. Within that
range, the scientists say, any object -- whether it's da Vinci's "Mona
Lisa" or an installation of Jeff Koons' vacuum cleaners -- may be
safely stored or place on exhibit.
 
"Up to 50% of construction cost for new museums and archival storage
facilities may go to highly specialized heating and cooling systems,"
Mecklenberg says, "Our research shows that such specialized systems are
unnecessary.  Most museums can adequately protect their collections
with commercially available technology, such as heating and cooling
systems used in grocery or retail stores."
 
Moreover, Mecklenberg says, specialized heating and cooling systems
that keep temperature and humidity stable can be expensive to operate.
Seasonal variations in temperature and humidity, particularly in
temperature climates, he says,  can mean mnthly energy costs that soar
to ten of thousands of dollars in order to maintain strict
environmental control.  For older or historic buildings, he says,
making use of conventional equipment avoidsthe structural damage that
might result from installing precision heating and cooling systems.
 
The materials research at CAL that has led to the new insighta about
temperature and relative humidity involves laboratory tests of the
properties ( physical, mechanical, chemical) of materials commonly
found in museums.  The overall goal of CAL researchers is to apply the
best scientific knowledge about various materials to the treatment and
conservation of cultural, historical, artistic and scientific
artifacts.
 
At CAL, artists' paints, for example, might be cooled and dried to
document responses to lowered temperature and humidity (too low, and
many paints and coatings become brittle and crack). Other materials --
wood, photographic emulsions, paper -- are subjected to high humidity,
orthey undergo accelerated aging through exposure to many potentially
damaging environmental factors, including heat, humidity, light and
various pollutants.
 
The research applies not only to the mseum environment.  Mecklenberg
and colleagues say.  Research at CAL has pointed to the risk of
cracking of acrylic paint if artwork is shipped in the cold and dry
environment of an airplane's cargo hold, while mechanical stress tests
show how paintings might hold up to the vibrations of a moving truck.
 
Computer modeling, the CAL scientists say, has given them another
powerful tool for predicting or confirming what happens to materials
under varying conditions. With today's advanced software, they can
analyze the materials in complex objects -- paintings, for example,
wherein layers of different coatings and surfaces make impossible any
meaningful laboratory analysis of how they will behave in concert.
 
"we can use computer models to see what should happen to materials
under different environmental conditions," Mecklenberg says. "We build
verification models to make sure it does happen.  as we begin to
understand materials more, we can let the computer takr over to
simulate a variety of different environmerntal conditions."
 
In general, the CAL researchers say, the low end of the
temperature/relative humidity range prevents biological damage from
microbial growth and minimizes chemical reactions that occur naturally
within objects over time.  At higher values of temperature and relative
humidity, they say, physical damage is minimized.
 
"The work is capable of defining the tolerance limits of large classes
of materials represented in museum collections," McCormick-Goodhart
says, "It means we don't have to study every single object.  That's a
breakthrough."