A second century Roman tablature is vulnerable to all sorts of hazards: wars, earthquakes, gravity. But even if the object makes it, as this one did, into the loving care of a museum curator, there is one thing that can still ravage it: the air. Calcium carbonate seeps out of marble over time, interacting with sulfur in the atmosphere to form an icky layer of black stuff called gypsum–the plaque of antiquities, if you will. You can’t clean it off without destroying the surface of the stone. And so it remains, on antique artifacts the world over.
But Duke conservator Adele de Cruz and Duke biochemical engineer Myron Wolbarsht have created a laser that can vaporize plaque, dirt and mold without altering the surface of the object. In a corner of DUMA’s conservation room, de Cruz points a small metal wand at a dingy painting. What she’s doing will help to make Duke University a leader in art restoration–and help to put the future Nasher Museum on the map.
The process looks incredibly simple: A particular wavelength of light interacts with the OH molecules in water or alcohol to remove, or “oblate,” the stuff on the surface. De Cruz puts a drop of alcohol on the painting (a forged Matisse she uses only for demonstration), puts a glass slip over it, and turns on the laser. The machine makes a fast, loud tapping sound, like a tiny jackhammer. To the touch, it just feels like a prick of warmth. But on the painting, it uncovers soot and grime without interacting with the paint surface.
De Cruz shows off pieces of antique sculpture that would otherwise languish in museum storage, not in good enough shape to put out on display. A 14th century monument head once plagued by mold is now clean. She shows off “before” and “after” photos of the Roman tablet, once covered in black specks, now restored. “The whole process is just physics,” she says excitedly. “But what makes it special is that it’s the chemistry of physics.”
Right now, there’s only one such laser in the world, and de Cruz is using it. She recently brought it to Florence, Italy–where she studied conservation as a graduate student–to share the technology with antiquities conservators there.
Just as scientific research is part of a university’s mission, so is restoration and technology part of a university art museum’s special mission. Conservation projects like this one have always been part of the DUMA’s work. But in the new Nasher, there will much more space for such undertakings. –Fiona Morgan