I asked GPT Neo to produce an article based on a recent news story about X-ray and AI technologies being used to identify images that have been painted over by artists when they re-use their canvases. What I ended up with sounds more like a surreal whodunnit.

The first of those paintings has been the source of the biggest intellectual mystery of the 20th century – Modigliani’s Portrait of a Girl. In the first weeks of the project, Bourached and Cann were drawn to the image of Modigliani’s lost girl, which was found in the National Gallery in London, in a crate at the bottom of a canal. 

“In the past it was just assumed that he was trying to hide her,” Bourached says. “Once we found the picture there was a tremendous sense of relief.”

Modigliani was the most successful, and the most expensive, painter of the 19th-century Italian Renaissance, and his portraiture has been widely admired and lauded. But there is a strange disconnect between images of Modigliani’s lost girl and the paintings themselves. 

Modern artists have long acknowledged the artfulness of Mod’s work, but the Tate’s current owner, the UK government, has refused to take ownership of her artworks.

“In the past, we’ve put the responsibility on the other person. But now we think it’s better if we find out who this unknown individual was,” Bourached says.

A few art experts think the portrait is, in fact, Modigliani’s lost girl. But the most recent X-ray, the one taken of the canvas in the National Gallery, shows a girl, and not a woman in a dress, as Mod’s lost girl does.

Bourached and Cann, who have been working on the project for the past year, are already convinced that this mystery woman in the museum had a male companion, and Mod’s lost girl is the man’s body.

“It’s hard to explain the girl in the picture,” Bourached says. “It’s a very odd shape. It suggests an elongated, squat, man in a jacket. But Mod had a broad, flat back.” 

The Art Newspaper quoted Bourached as saying: “We’ve been working on portraits of the late 19th century – the late-19th century. We have a lot of paintings of young women and some of the best ones are hidden by the artworks.” Modigliani’s Portrait of a Girl is the earliest painting to have been identified as originally being painted by Henri Rousseau. Modigliani worked from his own sketches. 

The paintings were bought by an art dealer for a mere £2,000 when he was 70. This portrait – a rare opportunity to discover a lost masterpiece – was acquired by the Tate in 2005. Modigliani died of unknown causes in 1898, and in 1917 he was appointed Professor of Art History at the Louvre. He did not live to see a new painting of his work displayed in the Tate. 

His art, like many in the 19th century, made its first public appearance in the late 19th century, when women in a wide range of dress, from Victorian to Art Deco, were painted by a range of artists including Wilkie, Courbet, Klimt, Cézanne, Seurat and even the great Pablo Picasso. 

This was a time of innovation: the likes of Modigliani, Renoir, Whistler, Pissarro and Duchamp all worked with a range of approaches, even if they did not all work together.

This art market was characterised by a shift in the balance of power. The likes of Picasso and Renoir were influenced by the new forms of expression that were emerging from the Surrealist movement.

The new techniques, like the use of paint to create a series of abstract, free-flowing visual abstractions, were also introduced by Duchamp, who was influenced by the new abstract expressionism movement. 

Meanwhile, the “fine arts” market was characterised by the emergence of the Impressionist movement, with many artists working in both mediums. As well as working with different materials, the Impressionists had their own individual methods, like the use of light and shadow.

I think Modigliani’s portrait of a girl is like a portrait of a woman. It has a strong silhouette. In real life, it was a girl.