Parts of $450 million Salvator Mundi were not painted by Leonardo, researchers claim

Salvator Mundi before its sale at auction in New York in 2017

Credit: Getty

A long-running debate over the authenticity of the world’s most expensive painting – Salvator Mundi by Leonardo da Vinci – has taken a fresh twist with claims that large parts of it are not the work of the Renaissance genius.

Researchers claim that the hands and arms in the masterpiece, which depicts Christ as the Saviour of the World – were not painted by Leonardo but were probably done by one of his pupils.

If confirmed, it could significantly lower the value of the oil painting, which was sold in 2017 for $450 million and is now reportedly in the hands of Mohammed Bin Salman, the crown prince of Saudi Arabia.

The new analysis was carried out by Steven Frank, a computer scientist, and Andrea Frank, an art historian, who will publish their research in a forthcoming issue of Leonardo, a publication of MIT Press in the US that focuses on art and science.  

Using an image analysis system called a convolutional neural network or CNN, they determined that while the head and shoulders of Christ were by Leonardo da Vinci, the arms and hands are most likely the work of someone else.

Areas in blue denote the parts of the painting that were not painted by Leonardo da Vinci, according to US researchers

The CNN system, designed to detect forgeries and shed light on controversial attributions, is able to “distinguish Leonardo from other artists,” Mr Frank told The Telegraph by email.

“We break a digital image of a painting down into small, overlapping tiles. We feed it one tile at a time, and the CNN assigns to that tile a probability that it was painted by Leonardo.”

The overlapping tiles are then reassembled and colour coded according to the likelihood of each part of the painting being the work of Leonardo.

Red signifies “highly likely”, gold “moderately likely”, green “moderately unlikely” and blue “highly unlikely.”

The hands and arms in Salvator Mundi emerged from the analysis as blue, signifying “a low probability of having being painted by Leonardo,” said Mr Frank.

Salvator Mundi before and after restoration

In the forthcoming academic paper, he wrote: “Artists who employed assistants and taught students (Rembrandt, for example) often directed those who could emulate the master’s technique to paint ‘unimportant’ elements such as hands, either for efficiency or as an exercise.”

An independent investigation by the Louvre in Paris also suggests that Salvator Mundi may not be all it seems.

Experts from the museum suggest that Leonardo originally conceived Salvator Mundi as a head and shoulders portrait and only later added in the right arm, which is raised in a blessing, and the left arm, which holds a crystal orb.

The right hand appears to have been painted on top of a black background, suggesting that the artist had “not envisaged it at the beginning of the pictorial execution.”

The research by the Louvre was meant to have been published in a book, but it was withdrawn after the loan of the painting to the Louvre in Abu Dhabi was canceled in 2018.

Leonardo da Vinci's Salvator Mundi, which sold at auction in New York for $450 million 

Credit: Reuters

The idea that the arms and hands of Salvator Mundi are not the work of Leonardo is refuted by Martin Kemp, Professor Emeritus of Art History at Oxford and one of the world’s leading experts on the Italian polymath. “I would dissent from that as strongly as I can,” he told The Telegraph.

He cast doubt on whether the CNN technique could accurately analyse the painting because it consists of multiple layers of paint and has suffered damage in the five centuries since it was created.

“It is a 500-year-old object. It is a layered, damaged picture. There’s a primer layer, under-painting, shading, glazing. CNN is a form of Artificial Intelligence and the results of analysis on a damaged Renaissance painting are likely to be unreliable,” he said.

Prof Kemp is among the scholars who believe that Salvator Mundi was indeed the work of Leonardo, though he says some tiny elements of the painting may have been done by his assistants.

“Some of the repetitive elements from his garment, for instance, could have been by someone from his studio. It could be that an assistant was let loose on that. But I definitely think it is a Leonardo painting.”