Rembrandt masterpiece made bigger by computer

Original had been clipped to fit through doors

Artificial intelligence has been called upon to solve the mystery of what Rembrandt's famous masterpiece, The Night Watch, originally looked like after an algorithm was used to recreate four missing sections.

The artwork, which depicts Amsterdam's civic guard of 1642, currently measures 143x172 inches but it was originally even larger.

When the painting, commissioned from Rembrandt by the members of the city's trained band, was moved to Amsterdam's city hall in 1715, it didn't fit through the doors, so it was trimmed on all four sides.

Vital fringe details were removed and the painting's composition was changed but not forever. Though these discarded strips were never found, a small contemporary copy, attributed to Gerrit Lundens and held by London's National Gallery, suggests what we have been missing for 300 years.

Scientists at Amsterdam's Rijksmuseum trained three sets of computer algorithms modelled on human brains — known as artificial neural networks — to recognize the differences between the original and the copy and fill in the blanks, Rembrandt-style.

The result is the world's first reconstruction of the complete masterpiece.

“It is wonderful to be able to now see with our own eyes The Night Watch as Rembrandt intended it to be seen,” said Rijksmuseum director Taco Dibbits.

“Rembrandt was asked to make a group portrait, but what did he do? He painted a story, bringing dynamics and movement. In the reconstruction, this is crystal clear,” he said.

By studying the two versions of the painting, the algorithms were able to reproduce Rembrandt's original down to a tee, including the perspective, style and colour palette.

“As far as I know, this is the first time this has been done,” Robert Erdmann, senior scientist at the Rijksmuseum, told The Daily Telegraph. “Neural network technology has seen an explosion (but) most of the innovation happens in Silicon Valley. It's unusual for a museum to be at the forefront of this research.

“It was quite a challenge. The copy was different ... it is a fifth of the size, it's by a different painter and in a different style, and it has a different palette.”

The final images were printed on to canvas, varnished, and mounted on metal supports very slightly in front of Rembrandt's painting to give a visual illusion of the original work.

“It really is the case that the cut-off pieces have an influence on the painting's composition,' said Dibbits. The sense of space at the top of the painting, he said, allows it to “breathe”, while shadows at the bottom increase the sense of perspective and movement. A balustrade on the left makes it clear the guardsmen are on a bridge.