SI press release

[Cary Karp <karp@nrm.se>]

The following press release is making the rounds. It seems reasonable to
post it here as well and I apologize to those who are already weary of
seeing it. I've been having a lot of trouble with relay hosts
(re-transmitters of e-mail) and need a lengthy message to send through a
new alternative that I'm testing, so it may be worth the spam in the long
run. You may also see this message as this week's desperate attempt on my 
part at getting some discussion going on this list.


    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 scientists 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 Mecklenberg, 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 from natural history specimens
    to archaeological artifacts, for example, 19th-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
    archives 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 relative 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 monthly
    energy costs that soar to tens of thousands of dollars in order to
    maintain strict environmental control. For older or historic
    buildings, he says, making use of conventional equipment avoids the
    structural damage that might result from installing precision
    heating and cooling systems.

    The materials research at CAL that has led to the new insight 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, or they 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 museum 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 take over to
    simulate a variety of different environmental 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."