Our building is closed but our work continues. Take, for instance, repairs on two exquisite bronze sculptures by Italian artist Francesco Bertos. The works date to around 1710, and they had had what's known as "documented losses" when they were acquired after World War II. The task to recreate the missing parts fell to Stephen Marder, consulting conservator.
"The artist's technique in building the piece is what enables us to repair it," Marder said, explaining that the bronze sculptures were cast from many smaller wax molds before their final assembly. Since Bertos reused some of the molds, Marder could look at a missing leg on one piece and find that identical leg intact on the other. He could then measure a perfectly fitting replacement.
When bronze is used in a lost-wax casting system, it shrinks 7 to 8 percent while cooling. To redo the pieces in bronze would require some incredibly precise gradations in scaling up the molds and would require some potentially risky-to-the-object welding. So this, Marder said, "is basically a visual restoration." One lower leg, one ankle and foot, and one chisel tip were molded in plastic, attached and then essentially faux finished to match the patina of the piece. He's almost finished.
"Whatever we are working on, there's the principle of reversibility," Marder said. "We have to be able to undo anything we do. Fifty years from now there may be new techniques or new ways of doing it, so this way we'll have well-documented repairs that are easier to spot."
You can see the incredible detail Bertos put in his work in these high-resolution photographs of Sculpture and The Drama. On the photo of The Drama a missing lower leg is visible. You can click here to see the replacement mold work and you can click here to see the remaining final touch—the coverup of the juncture between old and new. You won't see that crack when it's back on view in 2014.