Foekje Boersma, along with Kathleen Dardes and James Druzik, provided an informative summary of the debate regarding environmental standards in their presentation “Precaution, proof, and pragmatism: 150 years of expert debate on the museum environment.” The presentation began with a historical review, based in part on information obtained from AIC’s Conservation Wiki.
The Museum of Fine Arts Boston and the Cleveland Museum of Art were the first museums to set specific humidity recommendations, in 1908 and 1915, respectively. It is often stated that the development of environmental standards arose as a by-product of the storage of artworks in salt and coal mines during World War II, so I was interested to learn of earlier attempts at environmental control.
In 1940, Harold Plenderleith and George Stout said there was not adequate information to fix an “absolute standard” but suggested 60 – 65% relative humidity, chosen because it was easiest to maintain with stability. Later, Plenderleith, now working with Paul Philippot, prescribed a “region of security” of 50 – 65% RH. According to Boersma, these early conservators were pragmatic: although a set temperature and RH were specified, a greater emphasis was made on avoiding extremes. The local climate and historical conditions of the objects were also to be taken into account. Garry Thomson, who is often assigned either the credit or blame, depending on whom you ask, for the 50% RH/70° F standard, is misinterpreted according to Boersma. He was also pragmatic. Rather than endorsing the 50/70 rule, he merely predicted the increasing number of museum loans would lead to museums adopting that rigid standard.
Boersma attributes the widespread implementation of the 50/70 rule to the museum building boom in the 1970s. Architects and engineers wanted numerical targets, and conservators were happy to specify safe conditions. Sustainability was not much of a concern given cheap energy costs. But already by 1979, CCI was advising seasonal variations with gradual fluctuations. Boersma then skipped ahead to the 1990s and the controversial research of Charles Tumosa and Marion Mecklenburg at MCI, which said that materials aren’t as sensitive as previously thought.
Today, the debate on the museum environment has moved from conservators to museum directors and administrators. The Bizot Group, concerned about environmental and economic sustainability, pushed to broaden environmental standards by adopting new Guiding Principles and Interim Guidelines, influenced by those developled by the NMDC (the National Museum Directors’ Council). In response, guidelines were published many other groups, such as AIC, BSI, AICCM, and the Doerner Institut.
In order to clarify the debate, Boersma divides prevailing views into three categories: precautionary safety, proven safety, and pragmatic risk management. Precautionary safety, embodied by the Doerner Institut’s Munich Position, centers around the belief that “stable is safe.” Not enough research has been done on the response of objects to wider environmental conditions. To eliminate risk, objects should be kept under a narrow set of conditions. Supporters of the proven safety approach acknowledge that actual conditions are wider than 50/70 because tight standards are impossible to maintain. The proofed fluctuations of 40 – 60% RH and 50 – 70˚ F are acceptable. Pragmatic risk management reflects ideas of risk assessment developed in the 1990s. Resources should go to the reduction of the biggest risks to collections, which may or may not be climatic fluctuation.
In conclusion, Boersma wonders how conservators can function as a profession given such different views on a central topic. She references her ongoing research as part of GCI’s Managing Collection Environments Initiative, which is working to answer questions generated by the debate.
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AIC Blog Archives: Conservators Converse
Former Blog of the American Institute for Conservation