Can Technology Tell Who's Laughing Now?

June 23, 2008 — -- Perhaps it was the reassuring smile. Or was it something else?

One can only guess what it was that convinced a buyer to drop $4.5 million on a "laughing" Rembrandt portrait that experts had panned as a fake.

The painting, which sold in October at a British auction house, had been considered the work of a follower, rather than the master, and was valued at $3,100. But last week, an investigation by the Rembrandt Research Project confirmed that it was indeed a self-portrait by the legendary painter himself.

Although the high-stakes process of authenticating famous artwork is far from foolproof, modern technology has allowed investigators to probe masterpieces in novel ways. X-rays, for instance, revealed another painting beneath the self-portrait. The hidden image exhibited qualities similar to other Rembrandt paintings -- evidence that evaluators were unable to discern.

And now researchers at Dartmouth University hope to take it a step further by developing a computer program that may someday distinguish clever imitations from the real deal.

Museums have typically determined authenticity by polling historians and scholars until a consensus is reached. Experts, however, can sometimes disagree, get it wrong or end up stumped. During the 1930s and '40s, a painter named Han Van Meergeren showed just how tenuous this method was by passing off his forgeries as the work of well-known artists and making millions in the process.

"We rely on connoisseurship incredibly, but it's also the most fallible of all things," says Scott Schaefer, a curator at the J. Paul Getty Museum in Los Angeles. "And in the balance hangs thousands, sometimes millions of dollars."

Forensic science emerged as way to better spot knock-offs. The combination of carbon dating, X-rays and other hi-tech tools can pinpoint the age of the canvass, the chemical makeup of color pigments and purity of the materials -- all of which should coincide with the purported era the piece was created.

Still, historians say much of the headache with attribution can be blamed on a common practice during Rembrandt's time in which students were encouraged to emulate their mentors. Nearly everything -- from the teacher's technique to the types of paint used -- was often copied with the instructor's approval. Artists would sometimes even sign an apprentice's work to earn extra cash.