The original old master is an auction-house trick

When the Spanish government imposed an export ban last week on a painting attributed to the “circle” of the 17th-century artist José de Ribera, it was acting on a tip-off about the work’s potential identity. “It’s Caravaggio, completely. It’s incredible. It has great power,” a London-based art dealer who spotted it told the New York Times.

If so, the painting could be worth €50m or more on the open market, rather than its auction starting price of €1,500 as a quasi-Ribera. There is plenty of prestige and money to be made in identifying “autograph” works — those painted entirely by famous artists rather than made by apprentices in their workshops, or later imitations of their style. 

A global industry, including the leading auction houses Christie’s and Sotheby’s, is devoted to authenticating and selling works of art, but no one can honestly be sure of the status of an old master. Debate still rumbles over whether “Salvator Mundi”, which sold for $450m in 2017, is wholly the work of Leonardo da Vinci.

Christie’s gave “Salvator Mundi” its full imprimatur at the time, hailing it as “the greatest artistic rediscovery of the last 100 years” as it was acquired by Mohammed bin Salman, crown prince of Saudi Arabia. So it is decidedly awkward that a film released this week claims that experts who examined it for the Louvre concluded that Leonardo “only contributed” to the work.

“About suffering they were never wrong,/The Old Masters,” wrote WH Auden in his poem Musée des Beaux Arts. But we are often wrong about the old masters themselves. An auction house has a financial incentive to certify a painting as the sole work of a famous artist because the price will rise and there will be more prestige in selling it, but the reality is usually messier. 

In theory, the origins and authorship of a painting should make no difference to the experience of viewing it: the object remains the same, no matter how it is described. The so-called Vermeers painted by Han van Meegeren, the notorious Dutch art forger, did not change form when he confessed to his captors in 1945 to having faked them.

In reality, the pleasure we gain from a painting is deeply bound up with what the art philosopher Denis Dutton called its “expressive authenticity”. Knowing — or believing we know — who painted it, what the artist meant, when and where it was done and who has owned it, is part of the experience.

People who participated in one German psychology study responded quite differently to identical images, depending on whether they were told they were original works of art or copies. The images included Leonardo’s “Portrait of an Unknown Woman”, which is in the Louvre, and what was called a copy of the work painted by an apprentice under his supervision.

If they believed it was produced by Leonardo, they were more likely to agree with statements such as “this artwork is more extraordinary than [others] I have seen before” and “[it] is triggering a pleasant emotion for me”. A portrait’s provenance stirs the soul, even if it is an illusion.

Deciding whether a painting is the work of an old master or one of their followers is a matter of judgment. It can be scanned and X-rayed to identify all the materials and rule out crude forgery or copying. “Salvator Mundi” was painted on the kind of walnut panel used by Leonardo elsewhere and characteristically has powdered glass in its paint. But a lot still rests on the expert’s “eye”.

Martin Kemp, a distinguished art historian, authenticated “Salvator Mundi” as a full-blown work by Leonardo partly because of the way Christ’s hair is painted in a vortex. Similarly, the judge in a 2015 UK court case over whether Sotheby’s was justified in deciding that a painting was not a Caravaggio ruled that “the feather in the painting has a shininess that is inappropriate”.

This underlies the complex code for degrees of authenticity, from an autograph work to one “attributed to” an artist, by a studio or a “circle”, by a “follower”, or in the “manner of”. Paintings can shift categories depending on the latest opinion or scan, with their owners pressing for promotion.

One obvious problem is that provenance is always uncertain. Despite the claims made in the film, the Louvre confirmed the attribution of “Salvator Mundi” to Leonardo in an unpublished booklet. A deeper problem is that the entire edifice of definitions is suspect for Renaissance painters because it does not reflect how they worked.

Many scholars agree that most paintings of the period were collective efforts. They were created not by what Michelle O’Malley, a professor at the Warburg Institute in London, calls a “heroic, genius artist” but in workshops led by them. The idea of the individual old master emerged in the 18th century, at the same time as auction houses.

The inconvenient truth is that there is no clear answer as to whether or not a work is by Leonardo, even if fortunes rest on there being one. Not only is it an opinion, but the question itself may not even make sense. Reflect on that, next time you are in the Louvre.

john.gapper@ft.com