The Mark of a Masterpiece

Peter Paul Biro with an alleged Jackson Pollock.
Peter Paul Biro with an alleged Jackson Pollock.Photograph by Steve Pyke

Every few weeks, photographs of old paintings arrive at Martin Kemp’s eighteenth-century house, outside Oxford, England. Many of the art works are so decayed that their once luminous colors have become washed out, their shiny coats of varnish darkened by grime and riddled with spidery cracks. Kemp scrutinizes each image with a magnifying glass, attempting to determine whether the owners have discovered what they claim to have found: a lost masterpiece by Leonardo da Vinci.

Kemp, a leading scholar of Leonardo, also authenticates works of art—a rare, mysterious, and often bitterly contested skill. His opinions carry the weight of history; they can help a painting become part of the world’s cultural heritage and be exhibited in museums for centuries, or cause it to be tossed into the trash. His judgment can also transform a previously worthless object into something worth tens of millions of dollars. (His imprimatur is so valuable that he must guard against con men forging not only a work of art but also his signature.) To maintain independence, Kemp refuses to accept payment for his services. “As soon as you get entangled with any financial interest or advantage, there is a taint, like a tobacco company paying an expert to say cigarettes are not dangerous,” he says.

Kemp, who is in his sixties, is an emeritus professor of art history at Oxford University, and has spent more than four decades immersed in what he calls “the Leonardo business,” publishing articles on nearly every aspect of the artist’s life. (He even helped a daredevil design a working parachute, from linen and wooden poles, based on a Leonardo drawing.) Like many connoisseurs, Kemp has a formidable visual memory, and can summon into consciousness any of Leonardo’s known works. When vetting a painting, he proceeds methodically, analyzing brushstrokes, composition, iconography, and pigments—those elements which may reveal an artist’s hidden identity. But he also relies on a more primal force. “The initial thing is just that immediate reaction, as when we’re recognizing the face of a friend in a crowd,” he explains. “You can go on later and say, ‘I recognize her face because the eyebrows are like this, and that is the right color of her hair,’ but, in effect, we don’t do that. It’s the totality of the thing. It feels instantaneous.”

Other authenticators have also struggled to explain their evaluative process, their “eye.” Thomas Hoving, the former director of the Metropolitan Museum of Art, who died in December, liked to speak of the “ineffable sense of connoisseurship.” The art historian Bernard Berenson described his talent as a “sixth sense.” “It is very largely a question of accumulated experience upon which your spirit sets unconsciously,” he said. “When I see a picture, in most cases, I recognize it at once as being or not being by the master it is ascribed to; the rest is merely a question of how to fish out the evidence that will make the conviction as plain to others as it is to me.” Berenson recalled that once, upon seeing a fake, he had felt an immediate discomfort in his stomach.

In March, 2008, Kemp checked his e-mail and saw another submission—a digital image of a drawing on vellum, or fine parchment. Ever since Dan Brown published “The Da Vinci Code,” five years earlier, Kemp had been flooded with works, many of them purportedly embedded with cryptic symbols, and, after a lifetime of dismissing forgeries and copies and junk, he was instinctively wary. About thirteen inches long and nine inches wide, the picture showed the profile of a girl, on the cusp of womanhood, with pale skin and glowing brown hair pulled back in a long ponytail. Her left eye, the only one visible in the profile, had a lifelike translucency. Her upper lip pressed secretively against her lower one, and a red bodice peeked out from underneath a green dress. The artist had meticulously rendered the girl’s features with pen and colored chalks (“Her face is subtle to an inexpressible degree,” Kemp later wrote), and Kemp felt a shiver of recognition. He enlarged the image on his computer screen until it became a mosaic of pixels. He looked closely at the shading—it seemed to have been drawn with a left hand, just as Leonardo had done.

Kemp tried to contain his excitement. A major work by Leonardo had not been discovered for more than a century. This drawing had no clear provenance—a trail of invoices, catalogue listings, or other records that can allow a work to be traced back to an artist. Rather, the drawing seemed to have come, as Kemp later put it, “from nowhere.” In 1998, Kate Ganz, a prominent dealer, had paid a little less than twenty-two thousand dollars for the drawing, at an auction at Christie’s. (The auction house did not disclose the previous owner’s identity, saying only that the picture had been the “property of a lady.”) At the time, the drawing was thought to have been executed in the nineteenth century, by a member of a German school of artists known for imitating Italian Renaissance painters. If the drawing was by Leonardo, it had slipped past some of the world’s most respected connoisseurs and collectors—people whose eyes are honed to look for fortune in addition to beauty. As Hugh Chapman, an assistant keeper in the Department of Prints and Drawings at the British Museum, later told the Times, “The market is a fairly efficient place. This would be an amazing miss.”

A purported Pollock fingerprint on a stretcher.

Photograph by Georgianna Lane / Courtesy Fine Art Registry

In January, 2007, Ganz sold the drawing at her gallery in Manhattan for roughly what she had paid for it. As is common in the art world, the identity of the new owner was a secret. Officially, the purchasing agent was listed as Downey Holdings, a Panamanian business with an address in Jersey, in the Channel Islands, which is popular as a tax haven. The purchase was made under the guidance of Peter Silverman, a Canadian collector who has a reputation in the business (though he dislikes the term) as a “picker”—someone who scours auction houses for undervalued works. Silverman told me that he had bought the drawing for a collector in Switzerland who is one of “the richest men in Europe.” Many people in the art world have speculated that Silverman himself is the owner. He denied this, but added, “Even if it were true, I wouldn’t say.”

Upon seeing the drawing, Silverman thought that it had to be from the Renaissance, and before long, he said, he began to consider “the ‘L’-word”— Leonardo. He submitted the drawing to tests that have become a standard part of the authentication process. Many of the drawing’s pigments were analyzed, and it was determined that none of them had been invented after Leonardo’s time period. A sample of the parchment was sent to the Swiss Federal Institute of Technology, in Zurich, for radiocarbon dating. The parchment was dated between 1440 and 1650, making it conceivable that the drawing was by Leonardo, who was born in 1452 and died in 1519. After receiving these results, Silverman contacted Kemp and sent him the image.

As Kemp well understood, countless artists could have made the drawing in that two-hundred-and-ten-year span. And many modern forgers come out of the field of restoration, where they learn not only how to copy an artist’s style but also how to exploit historically appropriate materials: organic pigments, antique wooden frames infested with beetles, canvases blackened by centuries of smoke. In the nineteen-thirties, the notorious Dutch forger Han van Meegeren, who produced at least nine fake Vermeers, used a canvas from the seventeenth century that still had its original stretcher. (Like many forgers, Van Meegeren insisted that he was “driven by the psychological effect of disappointment in not being acknowledged by my fellow artists and critics.”)

Further pitting the powers of perception against the powers of deception are genuinely old forgeries, which would not be exposed by radiocarbon dating and pigment analysis. In Thomas Hoving’s 1996 book, “False Impressions: The Hunt for Big-Time Art Fakes,” he warned, “It’s the Renaissance works of art faked in the sixteenth and seventeenth centuries that are dangerous. These are nearly impossible to detect.” Making matters even trickier, many Renaissance artists operated studios where apprentices contributed to their works. Scholars now generally believe that the “Madonna Litta,” which hangs in The Hermitage, in St. Petersburg, and had long been attributed to Leonardo, was painted, at least in part, by an assistant named Giovanni Antonio Boltraffio. (The landscape shown through a windowpane is considered too prosaic to have been executed by Leonardo.)

Martin Kemp made a habit of cataloguing the mistakes of Leonardo’s imitators and forgers: an inadvertent right-handed brushstroke; a deadened effect from painting robotically; a failure to layer the paint so that light played subtly off it. The drawing of the girl betrayed none of these failings, and Kemp decided to examine the picture himself. After making arrangements with Silverman, he went to Switzerland. (It’s a joke of the trade that all valuable art works end up in Switzerland, Kemp said, but “it’s actually true.”) The drawing was in a warehouse in Zurich, protected by armed guards and invisible alarm sensors, which was known as the Bunker.

Kemp was escorted into a large, pristine room, where the drawing of the girl was carefully removed from a box and placed, face up, on a table. He circled around it for hours, lighting the work from different angles and staring at it so closely that his nose nearly touched the parchment. Not only had the drawing apparently been done with left-handed strokes; the artist, like Leonardo, had relied on the palm of his hand as a way of softening the shading. (An imprint was visible.) The figure’s proportions adhered to geometrical precepts detailed in Leonardo’s notebooks; for example, he had written, “The space from the chin to the base of the nose . . . is the third part of the face and equal to the length of the nose and to the forehead.” And didn’t the girl’s radiant iris resemble the eyes in Leonardo’s portrait “Lady with an Ermine”? Still, Kemp remained cautious. The reputations of scholars have been ruined after their eye was shown to be fallible. Dr. Abraham Bredius, who in the thirties was considered the greatest authority on the Dutch Old Masters, is now remembered best for having branded a van Meegeren forgery a Vermeer masterpiece.

Kemp returned to England, where for the next year he continued to interrogate the drawing. The hair style and the costume of the girl, he concluded, were similar to those worn in the Milanese court of the fourteen-nineties. The parchment had incisions suggesting that it had been removed from a bound codex; during the Renaissance, volumes of verse, compiled on sheets of vellum, were often dedicated to a princess upon her marriage or death. But, if this was the drawing’s origin, who could the princess in the drawing be? Sifting through members of the court, Kemp settled on the most likely suspect: Bianca Sforza, the Duke of Milan’s illegitimate daughter. In 1496, at the age of thirteen, she was married to Galeazzo Sanseverino, and died of an abdominal illness only four months later. Sanseverino, as Kemp knew, was a patron of Leonardo. Each new piece of evidence appeared to cohere. Kemp named the portrait “La Bella Principessa”—“The Beautiful Princess”—and, as he looked at the drawing, he could no longer suppress the sensation that had seized him when he first saw the portrait. In the fall of 2009, Kemp announced to colleagues and reporters that it was “the real thing”: a Leonardo masterpiece.

Other scholars and connoisseurs examined the drawing and agreed with Kemp. They included Nicholas Turner, the former curator of drawings at the Getty Museum, and Alessandro Vezzosi, the director of the Museo Ideale Leonardo da Vinci, outside Florence, who said that he didn’t have “any doubt” that it was authentic. At first, there was little dissent. Generally, connoisseurs are reluctant to repudiate a piece publicly, for fear of being sued by the owners for “product disparagement,” or even for defamation. The threat of litigation has often made the authentication industry a clandestine realm, with connoisseurs who refuse to communicate in writing and with confidential agreements that bind authenticators to silence.

“Give a man a job, and he’ll work all day. Teach a man to delegate, and he’ll take the rest of the day off.”

Nevertheless, some critics spoke up. Among them was Thomas Hoving, who discussed the drawing with me a few weeks before he died, at the age of seventy-eight. A flamboyant and imperious figure, who once wrote that he needed “great works of art for the uplift of my soul,” Hoving became an emblem of the modern connoisseur. He considered himself that “rare breed of cat” who could instantly detect a fake. And he told me he was sure that “La Bella Principessa” was too “sweet” to be a Leonardo. “His subjects are tough as nails,” he said.

Carmen Bambach, the curator of drawings at the Met, was also unpersuaded. The greatest scholar of an artist is not necessarily considered the greatest connoisseur, and with a diverse oeuvre there can be different authorities for each medium. When it comes to Leonardo’s drawings, Bambach’s eye is perhaps the most respected. “Not everyone’s opinion carries the same weight,” she told me. “It’s like in medicine, where a heart specialist looks at the heart and another specialist looks at the kidneys.” She added, “With Leonardo, you need the niche specialist.” Bambach pointed out that there is no other example of Leonardo having drawn on vellum. (Kemp concurred, but noted finding evidence that Leonardo had questioned Jean Perréal, a painter in the French court, about the technique.) Moreover, according to Bambach, there was a more profound problem: after studying an image of the drawing—the same costume, the same features, the same strokes that Kemp examined—she had her own strong intuition. “It does not look like a Leonardo,” she said.

When such a schism emerges among the most respected connoisseurs, a painting is often cast into purgatory. But in January, 2009, Kemp turned to a Canadian forensic art expert named Peter Paul Biro, who, during the past several years, has pioneered a radical new approach to authenticating pictures. He does not merely try to detect the artist’s invisible hand; he scours a painting for the artist’s fingerprints, impressed in the paint or on the canvas. Treating each painting as a crime scene, in which an artist has left behind traces of evidence, Biro has tried to render objective what has historically been subjective. In the process, he has shaken the priesthood of connoisseurship, raising questions about the nature of art, about the commodification of aesthetic beauty, and about the very legitimacy of the art world. Biro’s research seems to confirm what many people have long suspected: that the system of authenticating art works can be arbitrary and, at times, even a fraud.

“Come in, come in,” Biro said, opening the door to his elegant three-story brick house, in Montreal. Biro, who is in his mid-fifties, has a fleshy pink face and a gourmand’s stomach, and he wore black slacks, a black turtleneck, and black shoes—his habitual raven-like outfit. A pair of glasses dangled from a string around his neck, and he had thick sideburns and whitening black hair that stood on end, as if he had been working late. (“For me, this is not a nine-to-five job,” he later said. “I wake up in the middle of the night because something occurred to me. It’s basically every waking hour.”) In his arms, he cradled a miniature schnauzer. “This is Coco,” he said, petting the dog to keep it from barking.

He led me past a room with a piano and shelves crowded with art books, and climbed a long wooden staircase that opened into a living room and dining area. Sunlight poured through tall windows and illuminated, on almost every wall, oil paintings of landscapes rendered with jabs of bold color. The house had once been “a wreck,” Biro said, but he and his wife, Joanne, an accomplished mezzo-soprano, had spent the past two decades renovating it—tearing up floorboards, knocking down interior walls, and installing ceramic tiles. With a work of art, Biro liked to say, you want to preserve everything; with a house, you feel compelled to transform it. “Some people call it renovations,” he told me, at one point. “Others call it a disease.”

Biro speaks English with an accent that seems to combine traces of French and Hungarian—he was born in Budapest—which contributes to an air of unplaceable refinement. One person who knows Biro told me that he had a mystique of “royalty.” Though it was still early in the day, Biro reached into a long wooden rack filled with wine bottles and removed one. After examining the label, he poured himself some and offered me a glass. “Every drop is precious,” he said, before finishing his glass and refilling it.

Eventually, with Coco and another dog, a Jack Russell terrier, trailing us, he took me outside to a small courtyard that led to his laboratory, which was in a separate building. The courtyard had a fountain and was filled with plants that camouflaged what was, essentially, a vault. A pair of steel doors were bolted shut and there were two alarm systems, including one with motion sensors.

He unlocked the door to his workshop, revealing a large rectangular table with a movable microscope and a high-powered lamp. Stacks of paintings were propped against a wall. Biro was frequently presented with possible Pollocks and Raphaels and Picassos. When I visited him on another occasion, he had placed under the microscope a faded picture of Venice that was potentially by J. M. W. Turner. “Quite worn, quite damaged, but it has all the hallmarks of what a Turner should be,” Biro said. In the lower right corner, pressed into the paint, he had found a fingerprint. “You can actually see it quite clearly,” he said. I looked in the microscope and, sure enough, I could make out a smudged fingerprint: loops and whorls, a painting unto itself.

Biro said that he was using a scalpel to scrape away a previous restorer’s excessive overpainting, in an attempt to discern more of the fingerprint’s characteristics. A lot of money lies in obtaining this kind of information, he explained, which is why he had to suspect everything, and everyone, of deception. (One of Biro’s friends called him a “human lie detector.”)

“And the next thing I knew, I was kissing her, and two of her friends, I think one was a dude, then we all did Ecstasy, rented a limo, and went to Vegas—but I swear that’s all that happened.”

To my surprise, Biro showed me another laboratory, in a locked basement. Here, he said, he kept his most revolutionary device: a multispectral-imaging camera, of his own design, which was mounted on a robotic arm and scanned a canvas from above. The device could take photographs of a painting at different wavelengths of light, from infrared to ultraviolet, allowing him to distinguish, without damaging the work, the kind of pigments an artist had used. (Previously, tiny samples of paint had to be extracted and submitted to chemical analysis.) The multispectral camera could also reveal whether an older painting was hidden beneath the surface, or whether a picture had been restored. And if a fingerprint was present the camera could pick up extraordinary levels of detail. Biro once boasted that his invention surpassed “any camera today” and was “the only one of its kind in the world.”

As we spoke, I noticed that hanging on the walls were more landscape paintings by the artist whose works were displayed throughout Biro’s house. They gave the laboratory the feel of a shrine. Before Biro told me about his research into “La Bella Principessa,” and what he described as startling findings, he shared with me the story of how he became the world’s first authenticator of art works through fingerprinting—a story that began, curiously enough, with the very paintings I was staring at.

“They were done by my father,” Biro said of the paintings. “I’m surrounded by them.”

His father, Geza, who died in 2008, at the age of eighty-nine, was a serious painter. According to Biro, he studied at the Royal Academy of Fine Arts in Budapest, and was admired for his sweeping landscapes and allegorical street scenes. During the Second World War, he was drafted by the Hungarian Army, and was eventually captured by the Russians, who placed him in a prison camp. One day, while being transported in the back of a crowded Soviet truck, he tumbled off the side, and his left arm—like Leonardo, the one he painted with—got caught under the wheel. The bones shattered like icicles. After the war, he was released, and he returned to Budapest, where, despite a series of operations, he remained handicapped. “He had to learn to paint with his right hand,” Peter Paul’s older brother, Laszlo, told me. “It really battered his self-confidence.” Geza’s work grew progressively darker. “He was very pessimistic,” Laszlo says.

After Geza got married and had two sons, he took a job as an art restorer at the Museum of Fine Arts in Budapest. For all their seeming kinship, a restorer is the antithesis of a painter: he is a conserver, not a creator. Like a mimic, he assumes another person’s style, at the expense of his own identity. He must resist any urge to improve, to experiment, to show off; otherwise, he becomes a forger. Yet, unlike a great actor, he receives no glory for his feats of mimicry. If he has succeeded, he has burnished another artist’s reputation, and vanished without the world ever knowing who he is, or what he has accomplished. The art historian Max J. Friedländer called the business of the restorer “the most thankless one imaginable.”

While Geza became a skilled restorer, specializing in Baroque and Renaissance frescoes, he continued to pursue his own art. Some of his paintings were exhibited in Europe, Peter Paul said, and one hung at the Museum of Fine Arts. Yet Geza refused to conform to the Communists’ ideological vision of art, and he found himself increasingly shunned. “The last straw for him was when he submitted his work for a salon,” Peter Paul recalls. “The painting was rejected on the basis that it did not reflect Socialist optimism.” In 1967, still struggling to manipulate his left arm, he received permission from the state to undergo surgery at a hospital in Vienna. After the operation, he immigrated to Montreal, and a year later his family joined him.

Finally, he was free to be an immortal striver. Geza went to Newfoundland and the Northwest Territories, painting the gorgeous frozen landscapes. In Montreal, he set up a small gallery to show his work. He garnered some critical support and his work occasionally sold at auction, but money was constantly short, and he found himself, for a few dollars, sketching people who wandered in off the street. In the seventies, Geza converted much of the gallery into the Center for Art Restoration, and devoted most of his days to relining other artists’ canvases on vacuum hot tables, retouching chipped paint, and removing smudges and dirt with chemical solvents that stung the eyes. Peter Paul and Laszlo, who were then teen-agers, served as his apprentices. Laszlo, who became a skilled painter, said of his father, “He was very demanding. He was trained to adhere to a strict ethical standard, and that was passed on to us.”

Peter Paul dropped out of college to work full-time with his father, immersing himself in the technical aspects of restoration. Then, in 1985, an event occurred, he says, that led to his scientific breakthrough. A man walked into their workshop with an unframed picture that was so blackened with dirt that it was hard to make out much more than a faint rural landscape. When Peter Paul told him that it would cost at least two thousand dollars to restore it, the owner went pale, and offered to sell it for a few hundred. “We bought it with the idea that we would clean half of it, and leave the other half dirty and just hang it” in the shop, Peter Paul recalls. It would be the perfect demonstration of their restoration prowess—“a kind of before and after.”

Eventually, the Biros started to clean a small portion of it. They had to purge not only the grime but also thick overpaint from a previous restoration, which resembled clotted blood. “As we got into it more and more, and the cleaned area became larger and larger, we realized there was a rainbow on the painting,” Laszlo says. Radiant colors emerged: greens and yellows and blues. The picture showed sunlight filtering through a clearing sky, the rays spreading across a river valley with pale grass and delicate trees and a ruined stone church. The picture “reeked of a master’s hand,” Peter Paul says. The more he and his brother cleaned it, the more they became convinced that they were looking at a work by none other than J. M. W. Turner.

“La Bella Principessa,” which Biro has suggested is a real Leonardo.

Courtesy Lumiere Technology

If so, it was worth hundreds of thousands of dollars, and possibly millions. The men spent months researching the painting, trying to make the case that it was consistent with Turner’s work. After poring over topographical maps, they visited a valley in Millom, England, which they came to believe was the same setting as in the picture. Incredibly, as he and his brother stood there, Peter Paul recalls, the mist cleared and “we actually saw a rainbow.”

In 1987, they took the painting to the Tate Gallery, in London, to show it to the world’s leading Turner experts and connoisseurs. The verdict was unanimous—the painting was a tattered imitation. As Laszlo puts it, he and his brother were “very politely shown the door.” They had been dismissed by what they perceived as an arrogant art establishment—“an ivory tower,” as Laszlo called it. There seemed to be no due process. “They just throw opinions around,” Peter Paul said of some connoisseurs.

Before the Biros left the Tate, they say, they walked through a gallery that had several Turner paintings on display. Peter Paul paused in front of Turner’s “Chichester Canal,” peering at the pale-blue sky reflecting off the waterway, which made it seem as if the earth had been turned upside down. In the foliage of several trees, he says, he noticed tiny swirls in the paint. He looked more closely. They were from a partial fingerprint. He felt a jolt: he had noticed partial fingerprints embedded in the potential Turner painting as well. In both pictures, he says, the ridges were deep enough in the original dried paint that they could not have been left by the hands of an owner or a restorer; rather, they were a by-product of Turner’s technique of modelling paint with his fingertips. Indeed, Biro says, he subsequently found fingerprints in hundreds of Turner’s works, and wondered: Why not compare the fingerprint in an undisputed Turner painting like “Chichester Canal” with the one in his own painting, and see if they matched?

The desire to transform the authentication process through science—to supplant a subjective eye with objective tools—was not new. During the late nineteenth century, the Italian art critic Giovanni Morelli, dismissing many traditional connoisseurs as “charlatans,” proposed a new “scientific” method based on “indisputable and practical facts.” Rather than search a painting for its creator’s intangible essence, he argued, connoisseurs should focus on minor details such as fingernails, toes, and earlobes, which an artist tended to render almost unconsciously. “Just as most men, both speakers and writers, make use of habitual modes of expression, favorite words or sayings, that they employ involuntarily, even inappropriately, so too every painter has his own peculiarities that escape him without his being aware,” Morelli wrote. He believed that not only did an Old Master expose his identity with these “material trifles”; forgers and imitators were also less likely to pay sufficient attention to them, and thus betray themselves. Morelli became known as the Sherlock Holmes of the art world.

To many connoisseurs, however, the nature of art was antithetical to cold science. Worse, Morelli made his own share of false attributions, prompting one art historian to dismiss him as a “quack doctor.”

In the early twentieth century, as J. P. Morgan, Henry Clay Frick, and other wealthy Americans bid up prices of Old Masters, the search for a foolproof system of connoisseurship intensified. At the same time, the flood of money into the art market led to widespread corruption, with dealers often paying off connoisseurs to validate paintings. In 1928, the art dealer René Gimpel complained, “The American collector is prey to the greatest swindle the world has ever seen: the certified swindle.”

The public has long been suspicious of connoisseurship. As John Brewer recounts in his recent book “The American Leonardo,” about a Kansas City couple’s battle, in the nineteen-twenties, to authenticate a potential Leonardo, this distrust had to do with more than the system’s reliability; it also had to do with doubts about the authenticity of the art world itself, with its cult of prized artists, its exorbitant trafficking in aesthetic pleasure, and an élite that seemed even more rarefied than most. In 1920, the Kansas couple, Harry and Andrée Hahn, sued the powerful art dealer Joseph Duveen for half a million dollars after he told a reporter that a portrait they owned could not possibly be a Leonardo. The Hahns argued that connoisseurs offered only “air-spun abstractions and nebulous mumbo-jumbos,” and that “smart and tricky art dealers” ran a “racket.” Even the judge in the case warned jurors to be wary of experts who relied on means “too introspective and subjective.” (Though none of the leading connoisseurs considered the painting a Leonardo, and later technical evaluations confirmed their judgment, the trial ended in a hung jury, and Duveen paid the Hahns sixty thousand dollars to settle the case.)

The desire to “scientificize” connoisseurship was therefore as much about the desire to democratize it, to wrest it out of the hands of art experts. Before the Hahn trial, rumors surfaced that there was a thumbprint in the paint. One newspaper asked, “WILL THUMBPRINT MADE 400 YEARS AGO PROVE PAINTING IS LEONARDO DA VINCI’S ORIGINAL?” But identifying the author of a painting through fingerprints still seemed far beyond the reach of science, and the process of authentication remained largely unchanged until Biro came up with his radical idea.

After returning from London, Biro studied books on fingerprinting and conferred with a retired fingerprint examiner. He learned the difference between a latent print—which is transferred with sweat and often needs to be dusted or processed with chemical agents in order to be detected—and a visible print, which is either impressed in a substance or left by touching a surface with something on one’s fingertips, such as ink. He learned fingerprint patterns, including loops, whorls, and tented arches. And he learned how to tell whether two fingerprints had enough overlapping characteristics to be deemed a match. “He basically trained himself,” Laszlo recalls. “He read and studied everything.”

Biro asked the conservation department at the Tate for images of “Chichester Canal” that were sufficiently high in resolution to show the fingerprint. For days, Biro says, he compared enhanced images of the fingerprint with the one on the rainbow painting; he felt certain that they came from the same person.

“They just made a little money the old-fashioned way, Ben—they stole it.”

Yet the art establishment refused to recognize the painting based on his approach. (As Laszlo puts it, the art world is “very jealous and sinister.”) In 1994, after years of frustration, the Biros took the painting to a Turner scholar, David Hill, at the University of Leeds. He thought that the composition and coloring strongly pointed to the hand of Turner, and he enlisted John Manners, a fingerprint examiner with the West Yorkshire Police, to verify Biro’s conclusions. “Not my cup of tea, really,” Manners said of the painting at the time. “Of course, some Turner canvases are magnificent. Not this one, in my opinion.” Still, he said, the fingerprints definitely matched: “It is a Turner.” Hill called the fingerprints the “clinching piece of evidence.”

The story of the fingerprints circulated around the world—“BURIED TREASURE VERIFIED BY SCIENCE,” the Toronto Globe and Mail declared—and many Turner scholars relented on the question of attribution. “It was the pressure of the media,” Biro said. “They were beginning to look foolish.” In 1995, the painting, called “Landscape with a Rainbow,” was sold as a Turner at the Phillips auction house in London. An undisclosed bidder bought it for more than a hundred and fifty thousand dollars—a sum that would have been even higher had the painting been in better condition. It was the first art work officially authenticated based on fingerprint identification. Biro asserted that he had uncovered the painting’s “forensic provenance,” telling a reporter, “The science of fingerprint identification is a true science. There are no gray areas.” Having developed what he advertised as a “rigorous methodology” that followed “accepted police standards,” he began to devote part of the family business to authenticating works of art with fingerprints—or, as he liked to say, to “placing an artist at the scene of the creation of a work.”

In 2000, Biro took on an even more spectacular case. A retired truck driver named Teri Horton hired Biro to examine a large drip canvas, painted in the kinetic style of Jackson Pollock, that she had bought for five dollars at a thrift shop in San Bernardino, California. After inspecting the work, Biro announced that he had found a partial fingerprint on the back of the canvas, and had matched it to a fingerprint on a paint can that is displayed in Pollock’s old studio, in East Hampton. André Turcotte, a retired fingerprint examiner with the Royal Canadian Mounted Police, supported the results. But the International Foundation for Art Research, a nonprofit organization that is the primary authenticator of Pollock’s works, balked, saying that Biro’s method was not yet “universally” accepted. Biro, in a report on Horton’s painting, wrote that he had been warned that “science prying into the closed world of connoisseurship is likely to make me many enemies.” Horton, meanwhile, became a modern-day Harry and Andrée Hahn, dismissing the method of traditional connoisseurs as “bullshit,” and the whole art world as a “fraud.”

Biro told me that he maintains a firewall between his research and the sale of a painting, and that he receives the same fee—two thousand dollars a day—regardless of the outcome of his investigation. “If I stopped being disinterested, my credibility will be gone,” he said. But he felt “morally obliged” to stand behind his findings.

The effort to authenticate the painting became a crusade. Horton went on “The Tonight Show with Jay Leno,” and her struggle was valorized in a 2006 documentary called “Who the #$&% Is Jackson Pollock?” In the film, Biro is depicted as a champion of science and of a woman with an eighth-grade education battling an autocratic establishment. The main antagonist—“the effete, nose-in-the-air art expert,” as he later quipped of his role—is Thomas Hoving. He is shown, in a suit and tie, sitting before Horton’s picture and declaring, “Dead on arrival.” Later, offering a rationale for his response, he noted that Horton’s picture featured acrylic paint, which had not previously been documented in Pollock’s drip paintings.

Biro, undaunted, visited Pollock’s old studio and extracted pigment samples from the floor, where the artist had once spread his canvases and applied paint. In a report, Biro wrote that he had used a “microchemistry test”—a method of mixing a paint sample with other chemicals to analyze its characteristics. “The very first sample of paint I tested,” he said, “turned out to be acrylic.” He also revealed that gold paint from a matchstick embedded in the floor was the same as gold paint found in Horton’s picture. Hoving remained unmoved. He dismissed the fingerprints, and said of Horton, “She knows nothing. . . . I’m an expert, she’s not.” In reviews of the film, Hoving was denounced as a “pompous fool” and a “villain”; Biro was called a “hero.”

Based on Biro’s findings, Horton was offered two million dollars for her painting, but she held out for more. Biro assured her that the art world could not continue to resist a forensic method that had been used to convict criminals for more than a century. And though many connoisseurs and collectors opposed his technique, more and more accepted it. He told me that he had authenticated two Picassos, half a dozen Turners, a Thomas Hart Benton, and close to a dozen other Pollocks. Several of the world’s top connoisseurs sought Biro’s expertise. Three years ago, two leading Pollock scholars, Claude Cernuschi and Ellen G. Landau, cited Biro’s evaluation of a suspected Pollock, saying, “Artists’ fingerprints do not show up just anywhere. Their presence cannot be dismissed or simply explained away.” Around this time, Biro helped Martin Kemp attribute a painting, partly on the basis of fingerprints, to one of Leonardo’s assistants. In an earlier e-mail to a client, Biro wrote, “The world is changing. Not as fast as one would hope but it is changing nevertheless.”

In 2009, Biro and Nicholas Eastaugh, a scientist known for his expertise on pigments, formed a company, Art Access and Research, which analyzes and authenticates paintings. Biro is its director of forensic studies. Clients include museums, private galleries, corporations, dealers, and major auction houses such as Sotheby’s. Biro was also enlisted by the Pigmentum Project, which is affiliated with Oxford University. His work is published in museum catalogues and in scientific publications, including Antiquity and the official journal of the Royal Microscopical Society. In the media, he has become one of the most prominent art experts, featured in documentaries and news reports. (He was once mentioned in this magazine, in The Talk of the Town.) He even has a cameo—as the man who “pioneered the whole technique” of fingerprint authentications—in Peter Robinson’s popular detective novel “Playing with Fire”; the story is about a charming, “chameleonlike” con man who runs an art-forgery ring. On his Web site, Biro notes that law enforcement has adopted his approach: “My analytical techniques were presented internally at a training course at the F.B.I. I am not permitted to go beyond that.”

Biro told me that the divide between connoisseurs and scientists was finally eroding. The best demonstration of this change, he added, was the fact that he had been commissioned to examine “La Bella Principessa” and, possibly, help make one of the greatest discoveries in the history of art.

During one of the visits I made to Biro’s home, he offered to share with me what he had learned about “La Bella Principessa.” We were in the living room, and the sweet scent of his wife’s French cooking kept wafting in from the kitchen. “You’ve never tasted anything so good,” Biro said. He went over to a varnished desk, where there was a computer, and clicked on an icon. An image of the drawing appeared on the screen. He zoomed in on the upper-left edge of the parchment, and pointed to a small mark on the surface: a fingerprint. It looked like little more than a smudge, and I squinted at the blurry lines.

Even in a high-resolution photograph, the fingerprint was unreadable; Biro called it “complete visual confusion.” Many fingerprint examiners, he said, would have been stymied. Then, as if he were lining up a row of mug shots, he called up a series of photographs from a multispectral-imaging camera. Because the images had been made with different wavelengths of light, none of them looked exactly the same. In some photographs, the texture of the parchment—the background “noise,” as Biro put it—was pronounced. In others, the ridge patterns in the fingerprint were accentuated and the parchment all but faded away. From one photograph to the next, Biro said, “the smudge becomes clearer.” Still, it was not clear enough. His next step, he said, was “proprietary.” Using advanced image-processing software, he subtracted the background noise from each image, until only the clearest parts of the fingerprint remained. Finally, he said, clicking on another icon, “You get this.”

The smudge had been transformed into a more legible print: now, at least, there were the outlines of ridges and bumps. When I asked Biro if he worried that his method might be flawed, he said that during nearly two decades of fingerprint examinations he had “not made one mistake.” He added, “I take a long time and I don’t allow myself to be rushed.”

Biro showed me another fingerprint, this one taken from Leonardo’s “St. Jerome,” which hangs in the Vatican. It was the clearest fingerprint from an undisputed work by Leonardo. On the computer screen, Biro moved the image of the “St. Jerome” fingerprint alongside the one from “La Bella Principessa.” “See that?” he said, pointing to an elevated ridge, or “island,” in each print. The island in “La Bella Principessa,” he said, was identical in shape to the island from the “St. Jerome” fingerprint. He added that he had found seven other overlapping characteristics. The results, Biro said, indicated that the paintings had been touched by the same hand more than five hundred years ago, which pointed to one conclusion: “La Bella Principessa” was a genuine Leonardo.

For a moment, Biro stared at the prints in silence, as if still awed by what he had found. The discovery, he said, was a “validation” of his life’s work. After he first revealed his findings, last October, a prominent dealer estimated that the drawing could be worth a hundred and fifty million dollars. (The unnamed “lady” who had sold it at Christie’s for less than twenty-two thousand dollars came forward and identified herself as Jeanne Marchig, a Swedish animal-rights activist. Citing, among other things, the fingerprint evidence, she sued the auction house for “negligence” and “breach of warranty” for failing to attribute the drawing correctly.)

In the wake of Biro’s announcement, Peter Silverman, the Canadian who had helped acquire the drawing, told a reporter, “Thank God, we have the fingerprint, because there will still be those doubting Thomases out there, saying it couldn’t possibly be.” To object now, he said, would be to “go against science and say the Earth is not round.” Biro, meanwhile, was lauded around the world. As an Australian newspaper put it, “ART EXPERT CRACKS DA CODE.”

And so, with this final flourish, the glittering portrait of Peter Paul Biro was complete: he was the triumphant scientist who had transformed the art world. Like “La Bella Principessa,” the image was romantic, almost idealized—the version of Biro that was most appealing to the eye. But, somewhere along the way, I began to notice small, and then more glaring, imperfections in this picture.

One of the first cracks appeared when I examined the case of Alex Matter, a filmmaker whose parents had been close to Jackson Pollock. In 2005, Matter announced that he had discovered a cache of art works in his late father’s storage space, on Long Island. Ellen Landau, the art historian, said that she was “absolutely convinced” that the paintings were by Pollock. Biro was sent a photograph of a fingerprint impressed on the front of one picture. He identified six characteristics that corresponded with the fingerprint on the paint can in Pollock’s studio—strong evidence that the work was by Pollock. But, as more and more connoisseurs weighed in, they noticed patterns that seemed at odds with Pollock’s style. Meanwhile, in sixteen of twenty art works submitted for analysis, forensic scientists discovered pigments that were not patented until after Pollock’s death, in 1956. At a symposium three years ago, Pollock experts all but ruled out the pictures. Ronald D. Spencer, a lawyer who represents the Pollock-Krasner Foundation, told me, “Biro can find all the fingerprints he wants. But, in terms of the marketplace, the Matter paintings are done. They are finished.”

“Wasn’t this blue back in 1947?”

When I first talked to Biro about Matter’s cache, he had noted that no anachronistic pigments were found on the picture that he had authenticated, and he said that it was possible that Pollock had created only a few of the pictures, or that he had simply touched one of them. After all, Pollock was a friend of Matter’s parents.

His explanation seemed plausible, but I kept being troubled by other details relating to Biro’s Pollock investigations. For instance, it was peculiar that even though there were no documented cases of acrylic being used in Pollock’s pour paintings, Biro had easily found some on the floor of the Long Island studio—indeed, in the very first sample he tested. I contacted a leading forensic scientist in the art world who teaches at the F.B.I. Academy, in Quantico, Virginia, and who has done research in the Pollock studio. The scientist told me that he had spent hours combing the floor and had not found any acrylic. He added that a microchemistry test was not even considered suitable for identifying acrylic. As for the gold paint particles that Biro said he had uncovered on the studio floor and matched to the pigment in Teri Horton’s painting, Helen Harrison, an art historian who is the director of the Pollock-Krasner House & Study Center, which oversees Pollock’s old studio, told me that she did not know of Pollock’s having used gold in any of his pour paintings.

Reporters work, in many ways, like authenticators. We encounter people, form intuitions about them, and then attempt to verify these impressions. I began to review Biro’s story; I spoke again with people I had already interviewed, and tracked down other associates. A woman who had once known him well told me, “Look deeper into his past. Look at his family business.” As I probed further, I discovered an underpainting that I had never imagined.

One day, I visited the records office at the Palais de Justice, the provincial courthouse in downtown Montreal. The office was in a windowless, fluorescent-lit room, and, like a remnant of Soviet bureaucracy, it was filled with cardboard boxes and with clerks who were consumed with distinct, but equally dismal, tasks. I asked a clerk if there were any case files connected to anyone with the surname Biro, and after a long wait I was handed a stack of mottled folders. During the eighties and early nineties, more than a dozen civil lawsuits had been filed against Peter Paul Biro, his brother, his father, or their art businesses. Many of them stemmed from unpaid creditors. An owner of a picture-frame company alleged that the Biros had issued checks that bounced and had operated “under the cover” of defunct companies “with the clear aim of confusing their creditors.” (The matter was settled out of court.) As I sifted through the files, I found other cases that raised fundamental questions about Peter Paul Biro’s work as a restorer and an art dealer.

On February 12, 1981, Sam and Syd Wise, brothers who were art collectors in Montreal, stopped by the Biros’ gallery. Peter Paul Biro was present, along with his father, Geza. The restoration business was in the back of the gallery, and the Biros often wore white laboratory coats. Although Peter Paul was the youngest member of the family, people familiar with the company say that he often seemed to be the dominant figure. A lawyer who was involved in cases brought against the Biros said that Peter Paul was “the brains of the operation.”

Though the gallery was filled mostly with Geza’s landscape paintings, Peter Paul told the Wises that they had for sale an exemplary oil painting by Goodridge Roberts, the Canadian artist. The picture was signed and showed what appeared to be Georgian Bay, in Ontario, which Roberts had often rendered in his paintings. The Wises bought the picture for ninety-five hundred dollars. Soon afterward, Peter Paul informed the Wises that he had another landscape painting by Roberts, and the Wises, who had already sold the first picture to a local gallery, agreed to buy the second one, for seventy-five hundred dollars.

In 1983, Goodridge Roberts’s widow, Joan, happened to visit the gallery where the Wises had sold the Georgian Bay painting. She had been intimately involved in her husband’s work, keeping a catalogue of his paintings, and she was immediately drawn to the picture. As she subsequently testified, it mimicked her husband’s paintings, but the trees were “feeble imitations,” the play of the colors was jarring, and the signature appeared oddly slanted. Moreover, she had never catalogued the work. She went up to the dealer and cried, “That’s a fake.”

The Wises, alerted to the allegation, rushed to see Peter Paul Biro. “I indicated to him that it was very important for us to establish the authenticity,” Syd Wise later testified. Biro refused, multiple times, to divulge where he had obtained either of the paintings. According to the Wises, Biro insisted that the person who sold him the paintings was in Europe, and that it was impossible to contact him.

Soon afterward, three of the world’s most highly regarded experts on Roberts confirmed that they were fakes. As one of them later testified, usually “a man who makes a forgery makes mistakes,” and these had some obvious ones.

Customarily, art dealers are bound to stand behind what they sell, and the Wises refunded the gallery that had bought the Georgian Bay painting. But Peter Paul Biro insisted that the works were genuine—and that, in any case, the Wises had had an opportunity to investigate the paintings before buying them. He refused to reimburse the Wises, who ultimately sued. In an affidavit, the Wises said that Biro and his father had “perpetrated a fraud, in that they knowingly sold . . . a forgery.” The Wises were represented by G. George Sand, who handled many civil cases involving art. In 1984, during a sworn deposition, he questioned Peter Paul Biro. For the first time, Biro disclosed the name of the person who had sold him the Roberts paintings. “George Pap,” Biro said, adding, “Actually, the proper name is Zsolt Pap. Pap is the family name.”

Sand pressed Biro about Pap’s identity. Biro said that Pap was of Hungarian descent, and lived in Montreal. Sand seized upon this, asking, “Did you tell Mr. Wise that this person was in Europe?”

“No,” Biro said. (Later, at trial, he said that he had told the Wises that it was Pap’s father who was in Europe.) When Biro was asked why he hadn’t revealed Zsolt Pap’s name to the Wises, he said, “I didn’t want to.”

Sand sought proof of a financial transaction—a check or a credit-card payment—between Biro and Pap. Biro, however, said that he had obtained them in exchange for two musical instruments: a Steinway piano and a cello.

Sand was incredulous: “Is Mr. Pap a music dealer or is he an art dealer?” After Biro could not recall where he had originally purchased the cello, Sand suddenly asked him, “You ever been convicted of a criminal offense, sir?”

“No.”

“You are certain of that?”

“Yes,” Biro said.

Asked whether anybody in his family had done work on the paintings, Biro said that his father had merely cleaned them. (Later, when Geza was asked if he had done anything more, such as retouching, he said, “No, no.” They were “intact.”)

Sand demanded that Biro provide an address for Pap, and Biro eventually did so. But Sand told me that he twice issued a subpoena to that location—and that no Zsolt Pap ever showed up.

Meanwhile, Sand had obtained a court order to seize various possessions at the Biros’ gallery. Several paintings were confiscated, including one whose frame had a plaque engraved with the name John Constable, the English Romantic painter. When the case went to trial, Sand asked Biro if the Constable belonged to him, and Biro said that it was owned by a client and was being restored. Given the value of Constable’s work, Sand asked Biro if he had notified the owner that his painting had been seized. “No,” Biro said. “The client lived in Florida and he moved, and we could not locate him.”

“A Constable painting, sir, don’t you agree with me, is a very expensive painting?” Sand asked.

“Except that this painting was not a Constable.”

Biro said that the painting had been bought at an auction, in Montreal, for five hundred dollars.

“You are restoring something that was not a John Constable?”

“Sure.”

“I see. Even though the name plaque said ‘John Constable’?”

“Sure.”

Throughout the trial, the Biros and their attorneys maintained that the two paintings sold to the Wises were authentic, but to make their case they presented an art expert who was not a specialist on Roberts, or even on Canadian art. On September 3, 1986, the court found in favor of the Wises, and ordered Peter Paul and Geza Biro to pay them the seventeen thousand dollars they had spent on the pictures, as well as interest.

About two years after the Wises’ case, Sand was contacted by another former client of the Biros, an art-and-antique collector named Saul Hendler, who has since died. According to court records and interviews with Sand and Hendler’s wife, Marion, the Biros approached Hendler in 1983, saying that they had found a suspected Renoir, signed by the artist, which, if authenticated, was worth millions of dollars. The Biros asked Hendler to front them nine thousand dollars to buy the painting, a portrait of a nude woman; the Biros would then authenticate the work and sell it, sharing the profits. Hendler gave them the money. Not long afterward, Peter Paul Biro consulted a leading Renoir expert, who determined that the painting was a fake and that the signature was forged. The Biros refunded Hendler half his money, and eventually agreed to give him the painting, which still had some value as a decorative piece.

When Hendler picked up the picture, he thought that the composition looked vaguely different. He had previously made a photo transparency of the painting, and at home he compared it with the canvas he had just been handed. “My late husband was furious,” Marion Hendler told me. “Then I saw it, and I was horrified. It was clearly not the same painting.” Had the Biros sold the original painting without telling Hendler?

Marion and her husband went to the Center for Art Restoration, and confronted Geza Biro. Marion recalls that Geza—who often referred to himself with the honorific “Doctor,” though he lacked a Ph.D.—was charming but also arrogant: “It was as if he was the great artiste, and whatever he said was true.” One of Geza’s sons, she said, inadvertently began to “spill information,” revealing that Geza liked to “copy a real artist’s work.” She added, “The whole thing suddenly came together: He’s the one who does it. The father did this to our painting.”

Hendler, unable to get back what he considered the original painting, sued the Biros for the rest of the money he had paid. In a written response, the Biros called the allegations “false and untrue and defamatory,” adding that “the sole difference in the painting was the work which had been performed on the painting by the Defendants in lifting the paint in order to discover the original painting which had appeared on the canvas.” During the trial, which took place in 1992, Sand called to the stand an art expert who testified that the painting was not the same as the one Hendler had bought. The court agreed, awarding Hendler several thousand dollars. But Marion asked me, “What did we win?” She went on, “Where’s that piece of art? We never got it back. He probably sold it for a lot of money and we got this piece of junk in return.”

“Don’t you think it’s time we talked about Operation Doug?”

Lawsuits had piled up against Peter Paul Biro and his family business. In two instances, there were allegations that art works had vanished under mysterious circumstances while in the care of Peter Paul. In one of the cases, Serge Joyal, who is now a senator in Canada, told me that he left a nineteenth-century drawing with the Biros to be restored. Before he could pick it up, Peter Paul notified him that it had been stolen from his car and that there was no insurance. Biro, however, never filed a police report, and Joyal says that Biro pleaded with him to wait before going to the authorities. During their conversations, Joyal says, Peter Paul acted evasive and suspicious, and Joyal became convinced that Biro was lying about the theft. As Joyal put it, “There was something fishy.” Though Peter Paul said that there was nothing “suspect” about his behavior, and that he should not be held liable, the court awarded Joyal seven thousand dollars, plus interest.

Elizabeth Lipsz, a Montreal businesswoman who had once been close to Biro, and who won a lawsuit against him for unpaid loans, described him to me as a “classic con man.” Her lawyer told me that Biro “was so convincing. He was very suave, soft-spoken, but after a while you catch him in different lies and you realize that the guy is a phony.”

Within Montreal’s small art world, there were whispers about Peter Paul Biro and his father. But the lawsuits appear to have attracted virtually no public attention. In 1993, Peter Paul Biro filed for bankruptcy, and he never paid many of the judgments against him, including what he owed the Wises and Joyal. Lipsz’s lawyer said of Biro, “He oiled his way out of that whole thing. . . . He got away scot-free.”

When I met with Sand at his law office, in Montreal, he told me he was amazed that Biro’s history had not tarnished his reputation and that he had reached such an exalted position. He said that, for years, he had read with curiosity about Biro’s authenticating paintings using forensic science. He looked at me intently and asked, “What’s the deal with all those fingerprints?”

In December, 2004, Ken Parker, a New York private investigator who had no experience with the art world, went to Montreal and showed Peter Paul Biro a drip painting that he and his siblings had received from their father. Parker hoped that the work was a Pollock, and he had read about Biro’s celebrated efforts on Teri Horton’s behalf. Several weeks after Parker left his painting with Biro, he received an e-mail from him about fingerprints that he had found on the back of the painting. “You are so lucky,” Biro wrote. “I am able to confirm a match to a print that appears on a paint can in the Pollock-Krasner House. It is also the same print as the one on Teri Horton’s painting.”

According to dozens of e-mails between Parker and Biro, and tape-recorded conversations, Parker was thrilled by Biro’s findings, but over time he and his wife, Kathy, grew concerned. As Biro held out the promise of authenticating their painting, and thus making them a fortune, he kept asking them for additional funds for his research. At one point, he requested several thousand dollars for a camera platform, offering, in return, to “produce an image of your Pollock that could not be made any other way.” Then he wanted two thousand dollars to get his camera “up to speed.” Then came another request: “Can you continue to pitch in smaller amounts? I am now quite certain that with $5,000 I can have the unit up and running.” Biro also stressed that in order to improve the painting’s value he had to restore it perfectly. “I don’t want to see one rusty staple on it,” he said, adding, “I would be very happy if you sent me $5,000 as I have seriously underestimated this last phase of the work.” Kathy Parker later recalled, “Every time we turned around, he was asking for more money.”

Biro soon asked Ken Parker—whose late father and stepmother had won several million dollars from the New York Lotto—to make a much larger investment. Biro was part of an effort to launch a venture named Provenance, which would provide, as he put it, the “clever strategy” necessary to sell “orphaned” paintings for tens of millions of dollars. According to a business prospectus, marked confidential, Provenance would acquire art works that had been forensically validated by Biro and several colleagues, and sell them in a gallery in New York City. The company chose a thumbprint for a logo. The driving force behind the venture was Tod Volpe, an art dealer who had once represented celebrities, including Jack Nicholson and Barbra Streisand. Biro, who had suggested that Volpe might serve as the Parkers’ dealer, described him, in an e-mail, as “brilliant, resourceful, and extremely well connected.” Biro said that his brother, Laszlo—whose “knowledge was invaluable”—would also be a central part of the company. Once Provenance was established, Biro told the Parkers, “there really is nothing we can no[t] do.”

The plan called for raising sixty-five million dollars from investors, part of which would go toward buying J. P. Morgan’s old headquarters, on Wall Street, and turning it into a palatial arts complex anchored by a gallery. Surprisingly, at least five million dollars of investors’ money would also go to purchasing Teri Horton’s painting—even though Biro had authenticated the work and Volpe had tried to sell it. By capitalizing on the media interest surrounding the painting, the plan said, the work could be resold for between forty and sixty million dollars, maybe even a hundred million. Although Biro has always publicly maintained that he had no financial stake in Horton’s painting, Horton sent an e-mail to the Parkers saying that after the sale of her painting Biro would “collect” and that it would “set him for life.”

The business plan noted that Biro had access to “more than 20” other valuable orphaned paintings, all of which could be sold at Provenance. Among them were paintings by artists with whom Biro and his family had long been closely associated, including three by Turner and a landscape by Constable. The plan estimated that each year Provenance would accept anywhere from twenty to thirty new possible masterpieces for scientific evaluation, of which nearly half would be authenticated, creating staggering profits. (The forensic expert who works with the F.B.I. expressed surprise at this prediction, telling me that, in the overwhelming majority of cases involving disputed art, the work fails to be authenticated.)

“We’ve received many letters from your constituents urging you to stay right where you are.”

Provenance was cleverly tapping into the public’s desire to crack open the art world, offering the tantalizing dream that anyone could find a Pollock or a Leonardo or a Turner languishing in a basement or a thrift shop. The company combined the forensic triumphalism of “C.S.I.” with the lottery ethos of “Antiques Roadshow.” (An associate producer at “Roadshow” had already sent Biro an e-mail about possibly doing a segment on the Parkers’ “unbelievable discovery.”)

The public’s distrust of the cloistered art world helps to explain why a forger, or a swindler, is so often perceived as a romantic avenger, his deceptions exposing the deeper fraudulence of the establishment. When Han van Meegeren was tried for his Vermeer forgeries, in 1947, his lawyer insisted, “The art world is reeling, and experts are beginning to doubt the very basis of artistic attribution. This was precisely what the defendant was trying to achieve.” In fact, most art swindlers have no grand intellectual design; rather, they are, as Thomas Hoving once put it, “money-grubbing confidence men, delighted to cobble up something that will get by in the rush for big profits.”

According to Parker, Volpe asked him for a “contribution” of five million dollars toward launching Provenance. (In an e-mail, Volpe had assured the Parkers that “when people lie it takes a part of their souls with them.”) Even if the Parkers didn’t want to help open the gallery, Biro wrote to Ken Parker, he hoped that they would invest “about 1.5 to 2 million” dollars for his research and equipment. “I think you could really do something for art and science if you supported this (not to mention your painting),” Biro said.

Ken Parker estimated that, by this point, he had given Biro between “thirty-five and fifty thousand dollars.” Kathy Parker later recalled, “He basically took our money and we thought he was real. He’s got a great lab, has a great line. . . . Then what would happen was that he’d be away—‘I’m off to Paris with my wife for two weeks’—and he’d give us some reason.” She went on, “He came down to New York, he’s staying in wonderful hotels, eating, drinking—he loves to eat and drink. . . . And every time he wrote he’s, like, ‘I haven’t gotten to your work because I had the flu.’ ”

Biro previously had been suspected of creating an investment scheme around a seemingly precious object, with the promise that it would eventually reap huge profits. In the late nineteen-nineties, he persuaded a Canadian financial adviser, Richard Lafferty, who is now dead, to invest in a venture to authenticate and sell a work purportedly by Raphael’s disciple Perino del Vaga. Three of Lafferty’s colleagues confirm the story, as do letters, memorandums, and other documents.

Biro claimed that he and his brother had found the circular painting, which looked like Raphael’s “Madonna della Sedia,” at an antique store in Boston; Biro had purportedly found a fingerprint on it that matched a fingerprint on an undisputed work by Perino. What’s more, he said, he and his brother had invented a unique ultrasound instrument—they called it a Perinoscope—and used it to detect a note hidden inside a secret compartment in the picture’s frame. The note was written in Italian and was dated April 5, 1520—the day before Raphael died. The Old Master appeared to have dictated a message to Perino, just before his death. The note said, “These are the words of my master as he instructed me to say and to do. If my faithful Perino has finished my last Madonna he has now the greatest treasure of all in his hands.” Raphael’s signature appeared in partial form, suggesting that he had been too ill to finish writing his name.

According to colleagues, Lafferty, who had once been a combative and astute financial analyst, was nearing the end of his life, and had grown less mentally agile; bored and lonely, he was drawn to Biro. One colleague recalls that the painting, which Lafferty spoke of as the “holy grail,” gave Lafferty “something to live for.” In a 1999 letter, Lafferty wrote that he had already invested eight hundred thousand dollars in the project. Lafferty’s accountant, Luc Desjardins, told me that altogether Lafferty spent well over a million dollars—but the painting never sold. A research team at Harvard analyzed the secret message, and, according to Lafferty’s summary of its findings, it had never seen “sixteenth-century ink act as it does on that particular document.” Caroline Elam, a leading scholar on the Renaissance, suggested that the work was “a very skilled, elaborate and expert hoax.” Lafferty’s longtime business partner, Allan Aitken, told me that he believed that “Biro was either a shyster or a con man, and had found in Lafferty an easy mark.”

By the fall of 2005, Ken Parker had begun to look into the people behind Provenance. It turned out that Tod Volpe, in the nineties, had defrauded his art clients, including Jack Nicholson, of nearly two million dollars, and had served two years in prison. Parker discovered that one of Volpe’s principal partners in Provenance was also an ex-con, who had done time for tax evasion and for running a drug-smuggling operation in the United States. (Volpe told me, “We all have skeletons in our past.”) Parker confronted Biro, who, in a subsequent e-mail, told Parker that he had “severed all communication with Volpe.” To avoid any potential conflict of interest, he said, he was rescinding any request for investment money: “I must maintain absolute neutrality.”

Biro told me that his request for millions of dollars from the Parkers came after he had finished his authentication of their painting. But, according to e-mails at the time, the Parkers were still waiting for his final report. And only months after rescinding his request for money he asked the Parkers to fund another new project: a privately endowed department for him and a colleague at Oxford University. “Naturally it is 100% tax deductible,” Biro wrote, in an e-mail. “Those who support the foundation of a bold and new department for us at Oxford will have their name on a plaque or have the department named after them such as ‘The Ken Parker Department for Forensic Art History.’ Sounds cool?”

“It’s for you.”

Parker, meanwhile, launched an investigation into the provenance of his painting. He learned that his father had obtained the work from a couple named Thelma and Norman Grossman. Parker tracked down the Grossmans. According to Thelma Grossman, she had bought the painting for a few hundred dollars from a young artist in Brooklyn who was skilled at imitating famous artists. As she put it, it is certain that the painting “is not a Jackson Pollock.” Later, Parker had a forensic scientist examine several paint samples. The test indicated the presence of acrylic emulsion—the kind of paint that has not been documented in a Pollock painting.

In March, 2007, the Parkers’ widening inquiry led them to a company called Global Fine Art Registry. One of the main services of the registry, which is based in Phoenix, is to provide art works with a tag, rather like a Vehicle Identification Number, and catalogue them in a database, in order to create a record of their provenance. The founder of the company, Theresa Franks, although not well known in the art world, has cast herself as a crusader against fraud in a realm that she describes as the “last wild frontier.” Operating out of her home, she pursues her own investigations, hiring independent experts and posting reports on her Web site. (One of her recent campaigns was against a company named Park West Gallery, which, she alleged, was selling fake prints by Salvador Dali. The gallery’s founder, who called her attacks “cyber-terrorism,” sued for defamation. In April, a jury ruled unanimously in Franks’s favor, and awarded her half a million dollars in a counterclaim.)

Franks became particularly interested in Biro’s methods after Frankie Brown, an artist in California, told her that he had seen a photograph of the Teri Horton painting, in People, and wondered if it might be his own work. Franks hired as an expert Tom Hanley, the chief of police in Middlebury, Vermont, who had more than two decades of experience as a fingerprint examiner. Hanley told me that he approached Biro, who had previously stated about Horton’s painting, “My work is (and has been) available for evaluation to qualified experts.” Yet Biro declined to share his evidence, saying that Horton had objected to the idea.

Hanley was thus forced to rely on bits of information that Biro had posted on his Web site, several years earlier. The online report contains a photograph of the partial fingerprint that Biro said he had found on the back of Horton’s painting. In Hanley’s judgment, the impression lacked the kind of detail—the clear ridges and furrows—that is necessary to make a proper comparison.

After Hanley revealed his findings to Franks, she raised questions on her Web site about the reliability of Biro’s fingerprint methodology. Biro then inserted a clarification to his online report. It said:

For security reasons, several images in this report are watermarked in a way that is not apparent to the observer. The fingerprint images have also been reduced in resolution so as to render them unusable except for illustration.

I advise against evaluating the fingerprint images illustrated in this report as if they were the actual source material. Any attempt to do so is pointless.

Biro told me that such secrecy protected the privacy of his clients and prevented anyone from misusing the fingerprint. To Hanley, this was baffling: what forensic scientist avoids peer review and even admits to doctoring evidence in order to prevent others from evaluating it? “If what he found are truly fingerprints, why isn’t he sharing?” Franks asked me. In any case, Hanley, unable to examine Biro’s evidence firsthand, had reached a dead end.

Then Ken Parker told Hanley and Franks about his drama with Biro. Parker said that Hanley was welcome to examine his painting. For the first time, Hanley was able directly to observe Biro’s fingerprint evidence. He noted several fingerprints on the back of the picture, including two on the wooden stretcher frame, which were black, as if they had been made with ink. Looking through a magnifying glass, Hanley focussed on the most legible fingerprint, which appeared to be covered with a clear finishing coat, like a varnish. Parker said that before giving the painting to Biro he hadn’t noticed a fingerprint on it. “I don’t know where it came from,” he said. He said that Biro had told him he had used some sort of “resin process” to make it more visible. Hanley had never seen a print developed in this fashion. Based on the clarity of the impression, Hanley thought that the fingerprint had to be relatively new—certainly not from half a century ago, when Pollock was alive.

Parker also retained the services of Lawrence Rooney, a retired detective sergeant and latent-print examiner who had worked in the Suffolk County Police’s identification unit, and who had more than two decades of experience as a fingerprint analyst. Rooney agreed that the fingerprint appeared too recent to have come from Pollock. He was also alarmed by the “resin process,” and, as he wrote in a report, the use of a “liquid seal” coating was “beyond all acceptable professional methods of latent print preservation and opens the door to many valid questions relating to the latent prints’ origin of placement and development.”

Hanley kept staring at the way the fingerprints rested on the surface of the wood, without the usual smudging or obliteration. He noticed that they shared an eerily similar shape. And he began to wonder if he was seeing something virtually unheard of: forged fingerprints. In a 1903 Sherlock Holmes story, “The Adventure of the Norwood Builder,” the detective discovers that a criminal has made a wax impression of a solicitor’s fingerprint and then framed him by stamping the forged fingerprint at an apparent murder scene. “It was a masterpiece of villainy,” Holmes says. The scheme became a common trope in detective fiction, but there are almost no documented cases of a criminal forging another person’s fingerprint. In the nineteen-forties, a safe burglar named Nedelkoff set himself up as a fortune-teller in Eastern Europe, and asked clients to press their hands into a soft clay tablet. Later, he poured liquid rubber into the clay impressions, creating soft casts of their fingertips. During his robberies, Nedelkoff pressed his former clients’ fingerprints onto safes. (Eventually, his scheme was unravelled by police.)

There were only a few examiners with any expertise in forged and fabricated fingerprints, and Hanley recommended that Theresa Franks hire Pat A. Wertheim. A bespectacled man with gray hair and a thick mustache, Wertheim works in the crime lab of the Arizona Department of Public Safety, and is also a private consultant. He teaches fingerprint analysis to law-enforcement officials around the world and has published numerous articles on the subject. Though forged fingerprints are rare, he says, a person with expertise could produce one with a rubber stamp, or even with an engraving made from a photograph of a fingerprint.

On October 27, 2007, Wertheim went with Hanley to the Parkers’ house, on Long Island, to examine their painting. Looking at four fingerprints on the back of the stretcher frame and the canvas, Wertheim was struck by their extremely irregular shape—the bulges and curves along their boundaries. Then he noticed something even more peculiar. Each one of a person’s ten fingers leaves a distinct impression, and the elasticity of skin makes it all but impossible to leave precisely the same fingerprint impression twice. Yet the two most visible fingerprints on the Parkers’ painting, Wertheim says, were virtually exact overlays of each other: the same shape, the same pressure, the same ridge patterns. What’s more, the visible parts of the two other fingerprints also lined up perfectly with these prints. In his more than three decades as an examiner, he had never seen a set of fingerprints like this.

When Wertheim examined one of the prints closely, he could make out several bubble-like voids. Although a person’s sweat pores often leave voids in a fingerprint, Wertheim says that these voids were unusually big and elongated.

Wertheim had a hunch about what had caused the voids, and he went with Hanley to Pollock’s old studio. Wertheim examined the fingerprint impression on the paint can. It matched the clearest fingerprints on the Parkers’ painting, Wertheim says. Hanley then made a silicone cast from the impression on the paint can. Incredibly, Wertheim says, all four fingerprints on the Parkers’ painting fit snugly within the boundaries of the cast impression. As Wertheim suspected, the cast also produced similar voids—they were caused from air bubbles that had formed in the rubber.

Altogether, Wertheim says, he tallied eight characteristics that were inconsistent with normal fingerprints. In a final report, he concluded that all of them had been made by a cast from the fingerprint on the paint can. As he told me, the fingerprints “screamed forgery.”

When a forgery is exposed, people in the art world generally have the same reaction: how could anyone have ever been fooled by something so obviously phony, so artless? Few connoisseurs still think that Han van Meegeren’s paintings look at all like Vermeers, or even have any artistic value. Forgers usually succeed not because they are so talented but, rather, because they provide, at a moment in time, exactly what others desperately want to see. Conjurers as much as copyists, they fulfill a wish or a fantasy. And so the inconsistencies—crooked signatures, uncharacteristic brushstrokes—are ignored or explained away.

If a forgery’s success were to depend on fake fingerprints, rather than on the sly imitation of a painter’s style, it would represent a radical departure from the methods employed by art forgers over thousands of years. And yet such a forgery would perfectly reflect the contemporary faith in science to conquer every realm, even one where beauty is supposed to be in the eye of the beholder.

Many owners of faked art works are reluctant to bring charges that may demolish the value of their property—one of the reasons that art crimes are often difficult to prosecute. Early on, Parker had told Franks that, if he became convinced that Biro had perpetrated a fraud, “I fully intend to prosecute this guy.” In April, 2008, when Franks informed Parker that Wertheim had concluded that the prints were forged, Parker told her that he had his own news about the painting: “We sold it about two weeks ago.” He said that he had showed Biro’s authentication report to the buyer. Parker recently told me that a group of investors had bought the painting for a “substantial sum,” though he still owned a share in it. He suggested that Thelma Grossman’s story about buying the painting in Brooklyn might be “mistaken,” and he called Theresa Franks a publicity seeker, adding that he did not want to be part of a “witch hunt” against Biro. He told me, “I have no reason to believe it’s not a Pollock.”

On a recent summer day, I paid a final visit to Biro’s home. Biro told me that Laszlo would be joining us, and he soon appeared—a more compact and muscular version of his younger brother. The three of us sat around a table on a balcony overlooking the courtyard. Biro had opened a bottle of a Hungarian white wine (“a fantastic Tokaji”), and he calmly sipped from his glass as I asked him about the allegations that had been made against them.

Peter Paul said that the old lawsuits had involved relatively small amounts, and, as he later wrote in an e-mail, often stemmed from disgruntled “treasure seekers” who “hoped to turn a thousand into ten or even into millions and then turned on us and still make nasty comments because their greed did not turn to gold.” He said that although Richard Lafferty, the financial adviser, may have spent more than a million dollars on the purported painting by Raphael’s disciple, not all the checks went to the Biros. Laszlo added that Lafferty had “the last word” in what he spent. Peter Paul, who referred to the allegations by Lafferty’s colleagues as “hearsay,” told me that no scholar had questioned the authenticity of the picture or of the note tucked inside the frame. When I subsequently uncovered documents indicating otherwise, Peter Paul said, “I don’t recall anything of that nature.”

“And in what denomination would you like your ‘every last damn cent’?”

At one point, I mentioned that a scientist deemed it incredible that Peter Paul had found acrylic on Pollock’s studio floor with his “very first sample of paint.” He said that he had been referring simply to his “first visit” to the studio. I asked him why he had performed a microchemistry test, given that it is not an accepted method for detecting acrylic; he said that the test “was just one first step.” He assured me that he had no financial stake in Horton’s painting. (She had told me that she might “give him a gift,” but she could not “let that get out in the media that he has a percentage, when he does not.”)

I had heard that Biro had recently gone to New York and met with a Russian who was considering buying the Horton painting, for a few million dollars. It was true, Biro said, but he was no more than a facilitator between interested parties: “I connect them.” He acknowledged that he had been involved with Tod Volpe and the plan to create Provenance, but he said, “Eventually, basically, I just turned my back on it, because it became far too commercial in its scope and I didn’t see that the integrity of my work would be suitably protected.”

Laszlo added, “It would’ve been just way too racy.”

I asked whether their father had forged the fake Goodridge Roberts landscape, or the painting given to Saul Hendler, or any other works of art. Laszlo stood up, circling the table, and for the first time Peter Paul became agitated. “It’s upsetting,” he said. “It’s pure fantasy.” He went on, “It’s so easy to make this kind of an accusation. Because somebody’s a painter, therefore he can forge. It’s like saying that if somebody is a surgeon he can kill, because he’s got a sharp instrument in his hand.”

We discussed “Landscape with a Rainbow,” the purported Turner painting that was Peter Paul Biro’s first fingerprint-authentication case. There appeared to be notable discrepancies in the various statements that the family had made about the origins of the painting. Peter Paul Biro and Laszlo usually told the press, and had repeated to me, that they were present when the purported owner had taken it to their shop to be restored. They told me that Laszlo had purchased it. Yet, during depositions for Peter Paul Biro’s bankruptcy case, Laszlo said that his father had obtained the painting. When Laszlo was asked where Geza had acquired it, he said, “I don’t remember.” Peter Paul Biro, at the same hearing, said, “I don’t specifically recall the circumstances.”

After I pointed out such inconsistencies, there was a silence. Laszlo stammered, “What? No.”

Peter Paul finally spoke, insisting that he could not have said “such a thing, because we knew where the painting came from.” Aware that I don’t speak French, he asked, “Are these French documents?”

“No, they’re English,” I said.

When I asked Biro about the allegedly forged fingerprints on the Parkers’ painting, he peered intently at his glass of wine. I suddenly noticed how blue his eyes were. Calm again, he denied that he had ever forged a fingerprint. The “resin process,” he explained, was just a varnish applied to help the prints stand out. And he said of Pat Wertheim, the fingerprint expert, “He’s wrong. He’s presenting a theory and, in his conclusion, he treats his theory as fact. . . . And the fact that he’s producing this work for a do-it-yourself art-authentication Web site—for me, that’s quite tainted.” In an earlier written statement rebutting the allegations, he noted that without his unparalleled equipment many fingerprint examiners could not attain reliable results: “My laboratory is . . . equipped with an imaging system capable of Gigabit resolution in hyperspectral imaging, surpassing any camera in existence today. The instrument was developed and built here in the lab and it is the only one of its kind in the world.” Conventional fingerprint examiners, he told me, lacked the training necessary to evaluate fingerprint impressions on art works: “This is not police work.” Wertheim and Hanley expressed surprise to me that Biro, who had no formal training as a fingerprint examiner, somehow possessed unique skills. As Wertheim put it, “So Mr. Biro invented the concept, designed the camera, built it, and it is the only one in the world?”

Biro later noted that he had spent only a “few hours” in Pollock’s studio, in the “presence of staff,” making it impossible for him to have made a rubber stamp. But when I asked Helen Harrison, who oversees the studio, about this, she said, “That’s not true.” Her records show that he visited four times, once with Tod Volpe, and that he was “there for hours.” She said that she did not watch over him all that time; indeed, in her absence he had removed, “without authorization,” a match from the floor, which he took to Montreal to analyze for possible paint particles. (When she saw him holding up the match in the documentary “Who the #$&% Is Jackson Pollock?,” she demanded that he give it back, and he eventually returned it. Biro claimed to me that an assistant had given him permission to take it.)

He said Wertheim was wrong to think that the fingerprints on the Parkers’ painting had to be forgeries simply because they were so similar. Biro took my pen, wrote an “X” on his fingertip, and pressed it three times on my notepad. “Look at this,” he said, pointing to the faint “X”s. “All of them identical. It’s as simple as that.” I noted that Wertheim had told me he welcomed a second opinion from a qualified authority, such as the F.B.I. As I continued to question Biro about whether any fingerprint on the Parkers’ painting was a forgery, he suddenly asked, “What if maybe it is?” Though he disagreed with Wertheim’s analysis, his conclusion “could be right.” Still, Biro had said, this didn’t mean that he was the culprit: “Why is everybody after me?”

In the case of “La Bella Principessa,” Biro did not handle the drawing, and was sent multispectral images from another laboratory, which he then developed and enhanced. Martin Kemp, the Leonardo scholar, told me, “In terms of what Biro did for us, I have absolutely no problems with any potential ethical issues.” He emphasized that his opinion of the drawing did not depend on the fingerprint evidence: “I’m entirely confident that it is by Leonardo.”

“I had no idea his constant barking was a problem. Thanks for letting me know you’re bothered by it.”

A final verdict on whether “La Bella Principessa” is genuine may not be reached for years, but more and more connoisseurs have voiced doubts. Skeptics express surprise that there is no apparent historical record for the drawing, given that Leonardo was one of Italy’s most famous painters during the Renaissance. They note that vellum lasts for centuries, and that it would be easy for a forger to obtain old sheets. Many of the critics share the view of the Met’s Carmen Bambach: it just doesn’t look like a Leonardo. ARTnews, which has reported on Wertheim’s findings, recently interviewed Klaus Albrecht Schröder, the director of the Albertina Museum, in Vienna. “No one is convinced it is a Leonardo,” he said. David Ekserdjian, an expert on sixteenth-century Italian drawings, wrote in The Burlington Magazine that he “strongly suspects” it is a “counterfeit.” Other art critics have suggested that Kemp has succumbed to a fantasy.

In March, “La Bella Principessa” went on display at an exhibit in Gothenburg, Sweden, and Biro saw the drawing for the first time. The crowds were enormous. For several minutes, he stared at the portrait. “It was stunningly beautiful,” he said, adding, “I felt that Leonardo definitely had to have had a lot to do with the drawing.”

Kemp recently published, with a colleague, a book called “La Bella Principessa: The Story of the New Masterpiece by Leonardo da Vinci,” which contains a chapter by Biro, entitled “Fingerprint Examination.” In the manner of a law-enforcement officer presenting forensic evidence in court, Biro arranges the images of the “St. Jerome” and the “Principessa” fingerprints side by side, with arrows pinpointing what he identifies as eight overlapping characteristics between them. I asked Charles Parker—a latent-fingerprint examiner with more than thirty years of experience in the field, who has helped to establish guidelines for fingerprint examiners in the United States—to review the chapter. He said that most of the arrows don’t point to actual overlapping characteristics, just random details, and that, judging from the images presented, the partial fingerprint on “La Bella Principessa” is too poorly detailed for an identification to be made. “No other examiner I know would sign off on it,” he said. “I couldn’t even get it past the door.” Wertheim agreed with this assessment, and suggested that Biro’s approach was the equivalent of trying to identify a man based on seeing his ear poking out from behind a bush for a fraction of a second.

“The fingerprint community can get quite dogmatic,” Biro told me in another conversation. “They don’t like people who rock the boat, and I could be seen as a loose cannon to some, because I’m questioning a lot of things.”

Whereas Biro had once spoken of the absolute objectivity and infallibility of fingerprint analysis, he now sounded more like a connoisseur than like a scientist. “I’m trying to define, for example, what is the point that something becomes a matter of interpretation,” he said. “In other words, where is that line? O.K., on the one hand, fingerprint practitioners state that fingerprint identification is a science. I’m more toward the other side, where I’m convinced by my own personal experience that it is very much like connoisseurship, because of . . . things I see they don’t.”

In law enforcement, a fingerprint examiner can issue only a positive or a negative identification, and is prohibited from speculating on probabilities. But Biro told me that he was now “pushing into the gray areas.” When he first revealed his findings on “La Bella Principessa,” Biro did not use the term “match,” as is standard among law-enforcement analysts, and as he had done in his reports on the paintings owned by Horton and the Parkers; rather, he said that the fingerprint on “La Bella Principessa” and the print on Leonardo’s “St. Jerome” were “highly comparable.”

“What does that mean?” the forensic scientist who works with the F.B.I. asked me. “Homo sapiens and bull mastiff—are they ‘highly comparable’? Give me a break.”

By the time that Biro took on “La Bella Principessa,” his reputation had become so solid, and the public appetite for forensic solutions had become so strong, that he no longer seems to have worried about watermarking his evidence or presenting a perfect match. Many people, not just experts, can look at a painting and argue over what they see, but few individuals, inside or outside the art world, can evaluate fingerprints. In that sense, Biro’s authentications were far less democratic than traditional connoisseurship. Though he told me that he did not want to be “judge and jury,” he had positioned himself as a singular authority.

Jeanne Marchig’s lawsuit against Christie’s may finally lead Biro’s methods to be subjected to review by top fingerprint examiners. Biro emphasized to me that his findings in the case should not be “overblown,” and that he never meant for them to be conclusive: “I see this as the beginning of a process. For me, this is not a closed case.”

I asked him whether he might have been wrong in suggesting that Leonardo had ever touched “La Bella Principessa.” He looked up at the sky and said, “It’s possible. Yes.”

During one of my final visits, Biro led me through his lab, where a new stack of orphaned paintings awaited inspection. In an e-mail to me, he had written, “I am busy as a bee, now working on several Michelangelo attributions as well as a new possible Leonardo. I guess when it rains it pours. Fingered another Turner, too.” Some of his new research was to be featured in an upcoming documentary on PBS.

I followed Biro into his basement laboratory, where his father’s landscape paintings hung. I wondered what had consigned them to this fate—hidden from the public, seen only by an adoring son. They had, I thought, a certain anguished beauty, but they also seemed derivative. Perhaps Biro’s father had lacked that divine spark of originality, or perhaps he had sacrificed it while inhabiting the skin of immortal artists. In a corner of the laboratory, propped near Biro’s camera contraption, was Teri Horton’s canvas, splashed with blue and red and white paint. As I looked at it, I thought of Thomas Hoving and what he had seen in that initial instant. Connoisseurship is rife with flaws. It is susceptible to error, arrogance, even corruption. And yet there is something about that “strange breed of cat,” as Hoving referred to the best connoisseurs, who could truly see with greater depth—who, after decades of training and study and immersion in an artist’s work, could experience a picture in a way that most of us can’t. Connoisseurship is not merely the ability to discern whether an art work is authentic or fake; it is also the ability to recognize whether a work is a masterpiece. Perhaps the most uncomfortable truth about art is that such knowledge can never be truly democratic.

Biro showed me the back of Horton’s canvas and pointed to the fingerprint. With growing excitement, he told me that he was pioneering a forensic method that would further revolutionize the process of authenticating art: DNA analysis. I learned that he had reported collecting several hairs on Horton’s painting, which were the same brown color as Pollock’s. He said that he had also removed hairs trapped in the dried paint on Pollock’s studio floor and on other potential Pollock paintings. In an e-mail to a client, who paid him more than fifteen thousand dollars for DNA testing, Biro wrote, “If this keeps up I’ll be reconstructing Pollock’s toupee very soon.”

Biro was planning to use DNA analysis in a project that he said would rival that of “La Bella Principessa”: the discovery, in California, of a cache of more than fifty drip paintings possibly by Jackson Pollock. Biro, who had repeatedly examined the works, said that he had extracted a sample of hair that had been embedded in one of the pictures. With the help of the owners of the paintings, Biro had obtained a DNA sample from a living relative of Pollock.* Matching an artist’s DNA on a painting, Biro told me, would finally remove any doubt from the authentication process. It would be, he said, a “holy grail.” ♦

*Correction, August 13, 2010: The DNA sample was taken from Pollock’s aunt, not from a direct descendant, as originally stated.