Traditional Art Gets High Tech Nano-Scale Analysis
Spoons, forks, candelabra…The Dallas Museum of Art has the world’s largest collection of American silver objects from the 19th and 20th century. But curators and conservators don’t have much history on what they’re made of or how they were created. To investigate the artifacts, a scientist at the University of North Texas Dallas is using nano-scale tests.
In the basement of the DMA, Far below the glass display cases that hold sparkling gold and ivory, there’s a room with pieces of tarnished silver.
Fran Baas is the objects conservator here. And she, along with chief conservator Mark Leonard, are working to uncover the stories behind silver-plated pieces in their collection
Like this 19th century, silver-plated cruet set.
The foot-tall piece looks like a spinning carousel – with slots to hold glass bottles of oil and vinegar. The silver has elaborate embossed images of pheasants, rabbits, grapes and fish.
Just a few years ago, Leonard says, pieces like this might not have made it to the public.
“It probably would have sat in storage,” he says. “You wouldn’t want to take the risk of doing more harm.”
See, conservators don’t know the best way to clean and preserve the antique because little is known about how it was made. What’s beneath the silver plating? Nickel? Copper? How many times has it been plated in silver?
For a long time, the only way to find out details like these was to remove a hunk of the artifact for analysis.
“And quite rightly, most curators don’t like to have large chunks taken out of their works of art,” Leonard says.
Which is where traditional art meets new technology.
In a lab at UNT’s Discovery Park, there’s a massive piece of equipment with an even larger name.
It’s a dual beam ultra-high resolution field emission scanning electron microscope (SEM) and focused ion beam (FIB), better known as a FIB SEM.
Assistant Professor Marcus Young is using this machine to see what’s underneath silver-plating of artifacts, without leaving a visible mark.
“We remove a cube and look at in from an angle,” he explains.
Once you’ve placed the sample inside a small chamber, the two different beams go to work for hours at a time. The first beam, the ion beam, uses focused gallium ions to remove microscopic pieces of material from the sample, and the second, the scanning electron beam scans the surface of the material to produce images of the sample.
“And we see (…) that cross sectional layer of silver, and then sometimes they put down nickel, copper…”
Young says most American companies that made silver-plated teapots, vases, and candelabra, they kept their methods secret. And as manufacturing disappeared, that history was lost.
“The record is only from the advertisements and the manufacturers promoting the material,” Young says. “And they’re not telling you how they do it.”
The nano-scale investigation will help curators tell a story – Mark Leonard points to one antique candelabra from 1935. Analysis showed weak adhesion between the base metal and the delicate silver plating, so the DMA now knows to take extra precautions for display and care of the piece.
“It will not only tell us a lot about our own collection, but it should revolutionize the way that the field, as a whole looks at silver plate objects.”