When a team of art experts recently sought to determine whether or not "The Holy Infants," an obscure painting purchased for $1,500 at a London auction, was in fact a lost work by Leonardo da Vinci, they didn’t just rely on their voluminous knowledge of art history or aesthetic sensibilities honed by countless hours spent studying the Renaissance master’s body of work. Instead, they took the painting to a laboratory. They examined the painting’s surface under a microscope, extracted a fragment of wood from the frame so that it could be subjected to carbon dating, and bombarded the artwork with high-energy protons to identify the elements present in the pigments. They even brought in a fingerprint expert, who lifted a 500-year-old print from the painting and compared it to one found on an early sketch of Leonardo’s "Last Supper."

That’s just one example of how art authentication — that is, evaluation of a painting or sculpture to determine whether it is the genuine work of a master and not, say, a student’s copy or a clever forgery — has become an increasingly high-tech endeavor. Long gone are the days when authentication was the province of aficionados such as Bernard Berenson, the flamboyant 1930s American art critic and collector, whose judgments sometimes were based upon the emotional and physical sensations that he felt when staring at a painting. (If he experienced vertigo or felt depressed, it suggested to him that a painting was a forgery.) Instead, many of today’s art authenticators are part scholar, part scientist and part detective, and their tools range from particle accelerators to computer programs that analyze an artist’s brushstrokes for telltale patterns. However, while technology promises to eliminate much of the educated guesswork and perhaps solve some of the long-standing mysteries of the art world, some of the new tools are themselves controversial. Even advocates of scientific art authentication caution that their methods are not yet infallible. Though recent advances in computer analysis of paintings hold great promise of someday providing the definitive last word, at present it still remains easier to spot a fake than it is to conclusively identify a genuine masterpiece.