Leonardo's Lost Princess: One Man's Quest to Authenticate an Unknown Portrait by Leonardo Da Vinci

by Peter Silverman; Catherine Whitney

  I was about to enter just such an arrangement.

  5

  The Magic Box

  Nature never breaks her own laws.

  —Leonardo da Vinci

  After Nicholas Turner and Mina Gregori both expressed the view that my portrait might be a Leonardo, I could hardly contain my excitement. Could it be? On one level I was stunned by the possibility of it. On another, I was able to bring the critical eye of a collector to my find. Was she or wasn’t she?

  Was there perhaps another way to find the truth? I contacted my old friend Giammarco Cappuzzo, an independent art consultant in Paris. I’d known him for more than twenty-five years, and he had all the right contacts. “Where do I begin the authentication process?” I asked him.

  His response was immediate. “Take it to Pascal Cotte at Lumiere Technology,” he said. “He and his partner, Jean Penicaut, have quite an operation.”

  “Never heard of him,” I replied. “Are you sure he will help this thing along?”

  “So sure,” Giammarco replied, “that I’ll bet you a dinner at La Tour d’Argent.”

  “That’s a bit pricey. How about lunch?” I offered.

  He agreed. I didn’t want to lose the high-priced bet, but at the same time I was hoping I would find answers from Pascal Cotte.

  As a young boy growing up in Paris, Pascal Cotte was obsessed with the Mona Lisa. He recalled his mother telling him it was the most beautiful painting ever made, and at the tender age of eleven he took the metro to the Louvre to see for himself. He stood before the painting and had been studying it for two hours when a curious guard approached him. “Young man,” the guard said with a smile, “would you like a chair?” Cotte nodded, and he was soon seated in comfort. Tourists who wandered into the hall assumed that the precocious young man was there in some official capacity, and they began asking him questions. He answered enthusiastically, emphasizing what he saw inside and behind the painting.

  He found the experience thrilling. He was hooked.

  Cotte returned again and again throughout his youth, spending hours gazing at the face, curious about the secrets inherent in Leonardo’s most famous portrait. The Mona Lisa had long been characterized by variations of the word secretive. As Oscar Wilde proclaimed, “The picture becomes more wonderful to us than she really is, and reveals to us a secret of which, in truth, it knows nothing”1 More recently, the writer Umberto Eco weighed in, saying,

  I don’t think that in painting the Mona Lisa Leonardo just thought of himself as painting a portrait of a lady. I believe that he knew very well that he was creating something that would spark people’s curiosity for centuries to come. He must have known that generations of people would busy themselves trying to unravel a great mystery—a mystery which may or may not exist. Leonardo was a great clown, and he knew better than anyone how to play with people’s imaginations in order to create an impression of mystery.2

  It can be fairly stated that entire libraries could be filled with the speculations about this lovely lady and her mysterious smile. Young Pascal Cotte was merely joining a rather large fan club.

  Later, Cotte’s career ambitions led him to focus on engineering and invention rather than art criticism. He wanted to see beyond—to take the art apart and look inside. His cheerful round face, jaunty attire, and absentminded-professor air masked the dead-on seriousness of a scientist, the ability to meander in highly technical arenas. A brilliant engineer and scientist, Cotte had long been intrigued by the possibilities of bringing new photo technology to the business of art examination.

  He and his partner, Jean Penicaut, established Lumiere Technology in 1989—lumière means “light”—with the goal of illuminating the previously hidden secrets of the world’s great art.3 The centerpiece of his company was a very special camera that allowed a process called multispectral digital imaging, which electronically uncovered each layer of a painting, enabling one to see, in Cotte’s words, “like Superman.”4

  This revolutionary camera allowed a work to be digitalized at a resolution of 1,570 pixels per millimeter.5 To put that in perspective, a conventional professional camera achieves a resolution of 100 pixels per millimeter. It was as though one could see into the soul of a painting, to study each stroke and shading, and to do it digitally without in any way harming the original.

  The technique was also revolutionary because it resolved a problem that had plagued the discipline for more than a century: accurate, or true, color. The technology allowed each pixel to be given an exact scientific measure. In traditional photography, color data was restricted by two factors: (1) the conventional RGB (red-green-blue) system of primary colors, and (2) the light source used. That is, a photographer in New York did not have the same light as a photographer in Paris or Madrid, so their photographs could not be scientifically comparable.

  In April 2000, the European-financed CRISATEL project endorsed the use of Lumiere Technology’s multispectral camera and its lighting system for the archiving and digitalization of museum works. In 2004, armed with this endorsement, Cotte went to the Louvre with a bold request. He explained that his camera allowed him to photograph any painting, and he wanted permission to use the process on the Mona Lisa. The museum agreed!

  This was a particularly exciting venture for art historians, who had agonized over the question of how to properly separate the original from the protective varnish that had been applied in later restorations. Thanks to Cotte, there was a way to accomplish digitally what had been perilous physically.

  The session was scheduled to take place after hours. A nervous group of curators and security personnel gathered to supervise the delicate removal of the painting from its bulletproof case. With a full contingent of guards surrounding it, the Mona Lisa was carried to the photograph room in the basement of the Louvre while technicians constantly monitored the temperature, which was required to be 20 degrees Celsius (68 degrees Fahrenheit), with 50 percent humidity.

  Standing by as the frame and the glass were removed, Cotte felt his heart flutter. “I am not an artist or a curator,” he said later, his voice filled with awe. “But when you see Mona Lisa like that, naked, unadorned, you understand why the whole world says, ‘Wow!’”6 He had no doubt that he was gazing on the object of a lifetime’s love. It was proof, he thought, that any dream can come true.

  Once the Mona Lisa was ready, Cotte set up his camera. It was large and ungainly, and the technology was entirely new.

  Here’s how it worked: The camera projected a ray of white light across the surface of the painting. The ray passed over the surface thirteen times before re-creating a computerized version of the image that was, in Cotte’s view, closer to the original than one could imagine possible. The thirteen photos resulting from the scan accurately split the light spectrum from ultraviolet to infrared at the limit of the optical laws—into 240 million pixels (as opposed to 20 million by the highest performance commercial camera), generating 22 gigabytes of data. The result ran the spectrum from objects visible to the human eye to those that were invisible.

  Cotte began with a digital photograph of Mona Lisa. By digitally “removing” layers of varnish, he was able to construct a virtual image of the picture, unveiling its true colors—before time and restorers had altered them. The light actually went inside the painting, in a manner that seemed almost magical, superimposing all thirteen images on top of one another to form an accurate whole.

  Eighteen hours after entering the Louvre, Cotte emerged, ebullient, quipping, “I spent the night with Mona Lisa.”7 He had reason to be thrilled.

  For the first time in centuries, the true colors of the painting could be viewed. Most copies of the Mona Lisa are very dark, but the original colors, Cotte found, were quite vivid. For example, the sky was revealed as brilliant blue, painted with lapis lazuli, a very expensive pigment. Cotte also detected a fur-lined coat resting on the woman’s knee that is invisible to the naked eye, which helped to explain the odd position of her hand.

&nb
sp; Cotte was able to give special attention to the woman’s luminous face by enlarging portions with his powerful camera to more than 4,000 pixels per square millimeter. In the process, he solved the mystery of the missing eyebrows and eyelashes. This was something that had always disturbed and fascinated him. He could not imagine that an artist such as Leonardo, who worked with impeccable anatomical accuracy, would forget to give his subject eyebrows and eyelashes.

  He was not alone in this fascination. Art scholars have long debated the barren brow, trying to make sense of it. Most peculiar was the evidence that eyebrows and lashes once existed in the painting. Giorgio Vasari, who wrote the book The Lives of the Artists in 1550 (considered the first art history book, in the modern sense), describes the Mona Lisa thus: “The eyes are bright and moist, and around them are those pale red and slightly livid circles seen in life, while the lashes and eyebrows are represented with the closest exactitude—with separate hair drawn as they issue from the skin.”8

  Although it is uncertain that Vasari ever saw the portrait in person, he did know the Giocondo family so it is possible he might have viewed it. Vasari was also a great admirer of Leonardo’s writing at one point, “Occasionally heaven sends us someone who is not only human but divine, so that through his mind and the excellence of his intellect we may reach to heaven.”9

  Evelyn Welsh, a professor of Renaissance studies at Queen’s College in London, wrote extensively about women’s styles and fashions of the period. She declared, “I would absolutely stake my life on it that Lisa had eyebrows. She had eyelashes.”10

  Was she right? Using his magical technology, Cotte was able to discover a single strong brushstroke in the eyebrow area. Thank God—the Master did not leave his subject without! They had merely been lost to time and restoration. (It is unlikely, however, that the real eyebrows will ever be restored, except in digital form. Physically touching the painting would be a task fraught with danger. I know of no one who would be willing to take it on, now that the painting has achieved such iconic status.)

  Buoyed by his success with the Mona Lisa, Cotte now had a new ambition: to digitalize all of Leonardo’s paintings and create a database. His next stop was the Czartoryski Museum in Kraków, Poland, where Leonardo’s Lady with an Ermine was on display. This was one of Leonardo’s most famous works, a portrait of Cecilia Gallerani, who was a mistress of Duke Ludovico il Moro Sforza’s at the Court of Milan during the period when Leonardo was working there in the 1490s.

  Invited by Prince Czartoryski and his foundation to digitalize the portrait, Cotte set to work. Studying his digital impressions of Lady with an Ermine, he found that Leonardo’s brilliance was masked, to some extent, by overly rigorous restorations and overpaintings.

  “Although the painting’s overall condition is excellent, it is covered with innumerable tiny repaints,” he reported. “Those have been suppressed by computer, thus freshening up the tones in the Lady’s lovely face, her décolleté, the embroidered ribbon around it, the pearl necklace, her right hand, the black ribbon of the sleeves, the blue mantle and the red velvet of the gown, etc. The ermine had been retouched in the past equally. Thanks to the computer restorers its white fur, meticulously depicted by Leonardo, can be viewed again.”11

  He also discovered, to his horror, that restoration work had resulted in the partial removal of Cecilia’s eyebrows and eyelashes, and he wondered if the same fate had befallen the Mona Lisa.

  Cotte’s multispectral imaging camera opened up a new arena of art exploration and authentication. Leonardo’s blending method—called sfumato—was delicate and integrated. Prior to the existence of the digital process, there was no way to remove restoration touches or varnish without jeopardizing the integrity of the art itself. Indeed, one expert in the Leonardo technique once fretted that to touch the face in the Mona Lisa would be to potentially erase the famous smile. But now Cotte had found a way to do the job without jeopardizing the painting.

  In time, Lumiere Technology began to emerge as a vital player in the expertise and study of art history with a process that modified the traditional methods of investigation used by experts and museum labs to achieve high-definition digitization in one operation. Cotte and Penicaut were quick to assert that they were not replacing conventional expertise. Explaining and defending their process, they wrote the following:

  We get no other pride than to remain ourselves, innovative, listening to art historians, experts, collectors and players of museum life whose knowledge we seek only to enrich by providing them new evidence, scientifically proven for more certification. We are not art historians. We are experts in scientific imagery for fine arts. Like it or not, these scientific measurements of multispectral paintings open a new area of investigation, in the same way that medical imaging has enabled practitioners to work better. These images should be commented on, analyzed, compared and shared. Deny to Lumiere Technology, inventor of such process, the right to exist and to comment on the images under the pretext that we are not art historians is nonsense. Like radiologists, we provide a checkup, a first observation, and then refine it for other professionals. The only requirement for expertise and study is the use of more efficient tools to search for the truth. The multispectral analysis, as a scientific measurement of the substance of the artwork, seems to be one of the most sophisticated, if not the most successful. It is never too late to recognize a breakthrough and to use it.12

  On a spring day in 2008, I rode up to the front entrance of Lumiere Technology on the back of Cappuzzo’s Vespa scooter, clutching the portrait in my arms. (Kathy nearly fainted when she learned about my cavalier means of transporting our priceless lady. I don’t know what I was thinking—perhaps it was a reckless yearning to spit in the face of propriety. Fortunately, we arrived safely!) I carefully dismounted and carried my precious package into the building, where I was greeted by a beaming Pascal Cotte. I liked him immediately. He was vibrating with warmth and enthusiasm. I turned over my treasure, telling him only that it had been attributed to an unknown nineteenth-century artist.

  He asked me to be seated while he took a quick preliminary look, and he disappeared with the package. He was back within half an hour, his face flushed and his eyes gleaming. He bounced excitedly on the balls of his feet. “Do you know what you have?” he asked.

  I feigned ignorance, not wishing to let him know I knew. I wanted him to form a totally independent opinion.

  “On a hunch, I ran a digital scan of your drawing through my database and came up with many similarities that intrigued me,” Cotte said. “I believe this may be a portrait by Leonardo.”

  I grinned and admitted my suspicions. “I didn’t want to influence you,” I explained.

  Cotte was trying to contain his enthusiasm and view the matter objectively. This was a different challenge than investigating a painting like Mona Lisa, which had a proven authorship. Could he also use his technology to detect authorship?

  With Cappuzzo’s help making arrangements, we sent a tiny sliver of the vellum to be carbon-dated at the Swiss Federal Institute of Technology in Zurich. This was a crucial part of the authentication. If it were determined that the parchment was of a later era, all bets were off. And so the process began.

  Carbon-14 dating is a chemical examination based on the way natural elements age, and it can be used to test a material or substance that has a biological origin—such as vellum, cloth, or wood. Carbon is breathed in by animals and plants through the carbon dioxide in the atmosphere. Carbon-14, one of three carbon isotopes, is radioactive and subject to decay over a very long period. Its half-life is 5,730 years, which means that in that period, half of the carbon-14 isotopes will have decayed. By measuring the percentage of carbon-14 that remains in a test sample, it is possible to determine its age to within two hundred years.

  The most famous and controversial case of carbon-14 testing involved the Shroud of Turin, the cloth that is alleged to have been the burial shroud of Jesus. In 1988, carbon testing revealed that t
he age of the cloth was medieval, which means it could not have belonged to Jesus. That might have settled the matter once and for all, but there was so much interest in the Shroud of Turin, and so much passion among true believers about proving its authenticity, that speculation raged about possible explanations for the “false” result.

  In 2005, Raymond N. Rogers, a highly respected chemist and a fellow of the Los Alamos National Laboratory, revealed in a scientific journal that the entire cloth was much older than the test sample—at least twice as old, and possibly two thousand years old. The explanation: the corner that was tested had been subject to mending and thus contained newer material. Rogers’s discovery did not stop the controversy, and studies of the Shroud of Turin continue.13

  We knew that carbon-14 testing could not authoritatively establish that our portrait had been created in the fifteenth century, much less in Leonardo’s lifetime. But it could contradict the Christie’s attribution of the nineteenth century, and that’s what we were after. The carbon dating of the vellum showed that the drawing had with great probability been done between 1440 and 1650, which was within the perimeters of a fifteenth-century authentication. It was important evidence, although carbon dating alone wasn’t proof. Art forgers were known to use materials from a desired era. For example, Hans van Meegeren, who created phony Vermeers, used canvas from the seventeenth century. Nevertheless, the carbon dating was a first positive result in a long checklist, and Cotte and his technicians began their study in earnest.