There are thousands of silver artifacts in museum collections around the world, and keeping them shiny is a constant challenge. So scientists are using new technology to give conservators a helping hand. A team of researchers led by Ray Phaneuf, a professor of materials science and engineering at the University of Maryland, College Park, has partnered with The Walters Art Museum in Baltimore to investigate less labor-intensive ways to protect silver artifacts from tarnishing. The new techniques, which might keep silver surfaces shiny for longer than traditional methods, could help ensure that historically important artifacts are preserved for future generations to learn from and enjoy. The researchers will present their work at the AVS 59th International Symposium and Exhibition, held Oct. 28 Nov. 2, in Tampa, Fla.
Silver tarnishes when hydrogen sulfide in the air reacts with the silver, forming an unsightly black layer of silver sulfide on the surface of the artifact. If the tarnish appears on Grandma's silver flatware set, a little polisher and some elbow grease will easily remove it. But polishing, which works by dissolving or grinding away the silver-sulfide layer, can also remove some of the underlying silver, an undesirable outcome for priceless works of art.
Currently museum conservators can apply a thin layer of nitrocellulose lacquer to protect the silver. The coating is often hand-painted by a trained specialist and must be removed and reapplied an average of every thirty years. Phaneuf notes that it is difficult to apply a layer of even thickness over an entire piece, and the process of applying, removing, and reapplying the film is time-consuming.
"We did a quick back-of-the envelope calculation and found that for a big museum like the Metropolitan Museum of Art in New York, treating their entire silver collection with nitrocellulose films would likely be a never-ending task," says Phaneuf.
A quicker conservatio
|Contact: Catherine Meyers|
American Institute of Physics