Image copyright Reuters

A series of previously unpublished sketches claimed to be by Vincent Van Gogh are imitations, the Van Gogh Museum has said.

Experts at the Dutch museum studied photos of the drawings ahead of a press conference unveiling a new book showcasing the sketches.

The museum's researchers "were of the opinion that these could not be attributed to Vincent Van Gogh".

Publisher Le Seuil said "their authenticity is well established".

Written by art historian Bogomila Welsh-Ovcharov, who specialises in Van Gogh, the book is titled Vincent Van Gogh, the Fog of Arles: The Rediscovered Sketchbook.

The book claims the ink drawings were created in the accounts book of a hotel Van Gogh was staying at in the French city of Arles in 1888.

Amsterdam's Van Gogh museum said in a statement that its experts had also examined some of the original drawings.

The 56 high-resolution photographs "did not change their minds", they added.

Image copyright Reuters Image caption Art historian Ms Welsh-Ovcharov works at the University of Toronto

The Van Gogh Museum's director, Axel Ruger, said they had told the book's publisher about the museum's opinion on the sketches.

Speaking to the BBC, Mr Ruger said of Ms Welsh-Ovcharov: "That's her opinion. She has some experience and knowledge as well. We may have to agree to disagree."

Ms Welsh-Ovcharov has created a number of exhibitions on Van Gogh, including one at the Musee d'Orsay in Paris.

Researchers from the Van Gogh museum - widely accepted as the world's authorities on the artist - concluded that the style of the drawings were uncharacteristic of his work during the period and were unrefined, "clumsy" and "monotonous".

The team said another telling point was that the drawings in the sketchbook were executed in brownish ink, and this type of ink has never been found in Van Gogh's drawings from the period in question.

Experts also felt the artist was not very familiar with the places depicted, which was unlike Van Gogh. The Van Gogh Museum holds the largest collection of drawings by the artist.

But the book's editor, Bernard Comment, stood by the authenticity of the sketches, saying that the Van Gogh Museum had been wrong before and had dismissed work that was later proved to be his.

Le Seuil claimed the accounts book was found in the archives of the Cafe de la Gare in Arles where Van Gogh produced a prodigious amount of work over his year-long stay there.

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