Before a museum displays a piece of art, conservators need to test every new material used to build the enclosure.The wrong paint, fabric, or wood can off-gas volatile compounds that could harm the objects they’re meant to protect.
Museums typically test for these harmful emissions by conducting an Oddy test, which exposes copper, lead, or silver strips—used as stand-ins for the artifacts—to one of the materials in question. At the end of the test, conservators check the metal for visible signs of corrosion to decide whether a material is safe to use.
However, the entire process takes 28 days and is typically conducted at elevated temperatures and humidities that are not representative of indoor environments. These downsides motivated Sarah Styler, an atmospheric chemist at McMaster University, and graduate student Kay McCallum to develop an alternative method that’s similar to the Oddy test but can produce results faster and under more realistic conditions. McCallum presented the new technique during a poster session last week at AGU Fall 2022, a meeting of the American Geophysical Union, in Chicago.
The new method uses a microbalance that measures the resonant frequency of a copper-coated quartz crystal, which changes as a function of the crystal’s mass. When the researchers exposed the crystal to corrosive substances, such as a sealant that had previously failed the Oddy test, they saw the crystal’s frequency quickly decrease due to the accumulation of reactive products on the copper coating. During preliminary tests, McCallum was able to obtain results in as little as 3 h.
“The possibility of replacing the Oddy test with a rapid test that requires no subjective assessment sounds exciting,” says Capucine Korenberg, a scientist at the British Museum who was not involved in the work. She adds, however, that in order for this method to be widely adopted, it needs to be inexpensive and easy to use. Although more work needs to be done to vet the apparatus, Styler and McCallum believe their microbalance-based technique will be able to meet both criteria, enabling conservationists to quickly determine whether a new material can be used to store art.