Christie’s da Vinci Auction Reveals Why Forgers Love to Fake Masters

How can we be certain that a Leonardo is a Leonardo?

The artist behind La Bella Principessa has long been up for dispute. United States public domain

Update: Leonardo da Vinci’s “Salvator Mundi” sold tonight for a record-shattering $450.3 million, at Christie’s in New York City.

In 2015, I gave a talk on art forgery at the Albertina in Vienna. The director told me that, not long before, renowned art forger Wolfgang Beltracchi had told the media that one of the Paul Klee works in the Albertina collection was actually his handiwork. It’s a clever move for an attention-hungry, convicted art forger to make. It prompted a momentarily panicked check on the Klees in the collection, but it was quickly clear that they were all authentic. It had been a publicity stunt of a statement, they said, but it had served its purpose. The media took notice and the experts were sent scrambling, even if it proved to be smoke without a flame.

It was with this in mind that I read, in renowned art forger Shaun Greenhalgh’s memoir, A Forger’s Tale, that he believes he painted a famous lost, and recently rediscovered, work on vellum that most scholars believe is by Leonardo da Vinci: La Bella Principessa. And that he modeled it on a girl named Sally whom he knew back in the 1970s.

Lost works by Leonardo have resurfaced with encouraging, though surprising, frequency in recent years. In 2005, Leonardo’s Salvator Mundi was acquired by a consortium of New York-based dealers who had it restored, because of the centuries of grime that had clogged its beauty. It was so unrecognizable that it had been sold in 1958 for just £45 GBP, its authorship long forgotten. It would feature in a blockbuster 2011 Leonardo da Vinci exhibit at the National Gallery in London, and was sold in 2013 to Russian billionaire, Dmitry Rybolovlev, for $127.5 million, which, at something like a 283 million percent increase, may be a record. Up for sale again tonight at Christie’s, it’s expected to draw in at least that much again. Now, the work looks good, and its provenance is largely unchallenged. But the price inflation was almost certainly due to the painting’s inclusion in the London exhibition that served as the official stamp of approval, guaranteeing its authenticity, and its notoriety.

In 2013, yet another lost Leonardo painting appeared to have been found, stored in a Swiss bank vault. Portrait of Isabella d’Este is a painting that matches an authentic preparatory sketch that is stored at the Louvre. It has never been known whether the famously flighty Leonardo (who started scores more projects than he ever finished) actually made the painting, which was subsequently lost and only now has resurfaced, or whether he made only the preparatory sketch and left it at that. The painting was subjected to forensic testing at University of Arizona, showing with 95 percent probability that it dates to between 1460 and 1650 (carbon-dating rarely is more accurate than that). The pigments were also analyzed and are similar to those Leonardo used. Professor Carlo Pedretti of UCLA said, “There are no doubts that the portrait is the work of Leonardo.” So one expert thinks it looks good, the story behind it sounds reasonable and fits within known history, and forensic testing shows that it is at least from the correct period. Open and shut case?

Not quite. This work has not been universally accepted the way Salvator Mundi has, and while the forensic results reassure that it is not a modern forgery, whether it’s by Leonardo is still a matter of opinion. For one thing, it’s painted on canvas, and Leonardo and his studio always painted on wood panel. He did like to experiment with materials and methods, but the use of canvas is odd, as Martin Kemp noted at the time. And just because it matches an existing Leonardo drawing does not make it by Leonardo.

Da Vinci’s Salvator Mundi is up for sale on November 15 at Christie’s. United States public domain

Drawings and prints circulated around collections, and artists would often create their own versions of works based on works by artists they admired. There are many paintings of Leda and the Swan, for instance, inspired by Leonardo’s original (which is lost, last seen in 1625 at Chateau de Fontainebleau in France), with numerous artists having tried their hands at creating a copy. Forgers also know that it is far more convincing to create what appears to be a known, but lost work, than to copy something already extant, or invent something entirely new that goes against the historical record. The forensic tests tell us that Portrait of Isabella d’Este is pre-modern, but there were pre-modern copies after Leonardo, and there were forgers during the Renaissance.

And then there were works created not by Leonardo but by his studio—apprentices, students, assistants. This is a likely conclusion for this Portrait of Isabella d’Este. From a connoisseurship standpoint, this work just doesn’t look that good. It looks a level down from Leonardo, an A- where Leonardo is an A+. This was my reaction just from seeing a digital image of it online. For those in the “It’s not a Leonardo” camp, the prime suspect is Gian Giacomo Caprotti, nicknamed Salai, Leonardo’s main assistant at the end of his life, and the man to whom he left his estate when he died.

A copy of Salvator Mundi by Salai sold at Sotheby’s in 2007 for $656,000. That’s a nice chunk of change, but a far cry from $127.5 million. Like this portrait, it looks Leonardo-ish, but just not as good. Why is this distinction important? From a historical perspective, there are precious few Leonardo paintings extant: from 15 to 20, depending on which scholars you agree with, so any new Leonardo painting is big news. But financially, there is a world of difference. A copy after a lost Leonardo original, even by an established artist like Salai, is worth around 200 times less than the original would be.

Then there’s La Bella Principessa, sold in 1998 as an 18th century German work. In 2010, Martin Kemp published a book that makes a very compelling case that the chalk drawing is the work of Leonardo—he even found a book in Warsaw with a page missing that matches the paper on which La Bella Principessa was drawn, and forensic test results suggest that the paper was made at least 250 years ago. But other scholars were not convinced, and the work was not included in the 2011 Leonardo exhibition in London. As Greenhalgh explained in his book, when he saw Kemp’s book with Principessa on the cover, he wasn’t certain that this version of La Bella Principessa was  even his. Might it have been a copy of a forgery?

Shaun Greenhalgh is not the only suspect character who has been linked with La Bella Principessa. Peter Paul Biro was profiled in a New Yorker article by David Grann, in which it was alleged that he and his family were involved in fraud related to art, and to La Bella Principessa in particular (Biro subsequently sued the New Yorker for defamation and lost). Needless to say, the work is a hot topic.

With rival opinions, and the waters made murky by statements by forgers, how is one to know whether a Leonardo is actually by Leonardo?

There are three tools that experts use, in an attempt to determine a work’s authenticity: Connoisseurship, provenance and forensic testing.

Connoisseurship, an innate knowledge of an artist’s style, is normally considered the least reliable manner of authentication, since it relies on subjective (although theoretically expert) opinion. The work was first attributed to Leonardo by a scholar, Cristina Geddo, in 2008, based on the work’s quality and resemblance in style to other Leonardo works (a subjective evaluation) and the left-handed cross-hatching. (Leonardo was left-handed at a time when natural lefties were encouraged to becomes righties as, in Italy, left-handers were considered sinister—the very etymology of “sinister” comes from the Italian, sinistra, for “left.”)

Provenance, or the documented history of an artwork, is often incomplete when dealing with works thought to be centuries old. Kemp did indeed find a book, called the Sforziad, which was made during Leonardo’s time in Milan, and he believes that this drawing was cut from the book—he even spotted where the page was missing in the original. The book was rebound circa 1800 (a factor that may prove important). But the modern provenance of the drawing dates to 1955—at least twenty years before Greenhalgh claims to have made it.

The forensic testing is what we moderns tend to feel is the determining factor. In our CSI mindset, scientific tests should lead to black and white results: It’s by Leonardo or it isn’t. But the forensic tests on this paper appear to neither authenticate it as a Leonardo nor as a Greenhalgh. If it was by Leonardo, then it was made in the 1490s. If it was by Greenhalgh, then it was made circa 1975. The test results suggests that the paper was made “at least 250 years ago” which, as Guardian art critic Jonathan Jones notes, is “250 years before Greenhalgh, but 250 years after Leonardo.” Jones also argues on the connoisseurship front, stating that “the real giveaway is the total absence of an emotional dynamic between this young woman and Leonardo” and that the hairpiece in the profile portrait is “too clumsy, too crude to be a real Leonardo conception.” But there are also pentimenti in the drawing—underdrawings that do not precisely match the finished surface drawing, which suggest an evolution of the work during the artistic process. Copies, and in almost all cases forgeries, replicate a finished project, and do not include pentimenti, which can only be seen using x-rays or infrared spectroscopy.

But one factor may have been overlooked. The best, most detail-oriented forgers, like Eric Hebborn, managed to acquire authentically old supports for their forgeries, and create fraudulent works upon them. Hebborn would buy Early Modern books in order to reuse the paper. The paper, then, is indeed old, and would of course stand up to forensic tests. Thus paper testing to “at least 250” years ago could be used for a modern forgery. Greenhalgh claims to have found a piece of vellum from 1587. Kemp countered that this was “ridiculous” and pointed out that the white pigment in the drawing is also “at least 250 years old.”

In the case of La Bella Principessa, opinion remains divided. Some experts believe it looks like Leonardo, others do not, thus connoisseurship is insufficient proof. The provenance is odd, with little documented history prior to 1955, but the 1955 date means that Greenhalgh could not have made it (although one could argue that the 1955 provenance could be a fake—and the balls rolls on). The forensics, likewise, are inconclusive. That the materials, vellum and pigment, are “at least 250 years old” seem to eliminate Greenhalgh’s claim (though he argues that he was able to acquire sufficiently old raw materials, something he did not bother to do in most of his other known forgeries). But since the forensics do not date the materials to circa 1500, then they cannot firmly attest to its Renaissance origins.

What we have is a layer cake of complexity and no real answer. There was certainly an original page in the Sforziada that is missing and was likely illustrated by Leonardo. But that original could still be lost. When the work was rebound around 1800, a copy or a forgery (the difference between these two terms is the intent to deceive) may have been made, and that copy is what is now circulating. But there may also have been a modern copy or forgery, or several. There are numerous copies of other Leonardo works, most famously of Mona Lisa, many of which were made during or shortly after Leonardo’s lifetime.

How can we be certain that a Leonardo is a Leonardo? When his confirmed works, provenance, connoisseurship and forensics appear to be in sync. Though there are always scholars who argue otherwise, since art history is an inexact science, most are on the same page with most of his works. But a great many remain in this limbo of opinion and indefinite test results. Which makes for a measure of mystery, perhaps some frustration, but certainly lively discussion.

Dr Noah Charney is a professor of art history and best-selling author, based in Slovenia. His latest books include Slovenology: Living and Traveling in the World’s Best Country and The Collector of Lives: Giorgio Vasari and the Invention of Art. Find him at Christie’s da Vinci Auction Reveals Why Forgers Love to Fake Masters