What could be an earlier version of Leonardo da Vinci's "Mona Lisa" was unveiled in Geneva along with research hinting the piece was indeed the work of the Italian master, although some experts said the claim was unlikely.
Carefully pulling back long velvet white drapes, members of the Zurich-based Mona Lisa Foundation revealed what looks like a younger version of the world's most famous painting to a room crammed with reporters and television cameras.
Foundation president Markus Frey said the purpose of the event was to "present all the evidence showing that the great artist Leonardo da Vinci did in fact paint two versions of the Mona Lisa portrait."
It was time, he insisted, to "give that stunning earlier version the place in history which it deserves after such a long period in obscurity."
The woman in the radiant, gold-framed painting -- which had been locked for more than 40 years in a Swiss vault -- bears a striking resemblance to the Mona Lisa, although her oval face is clearly younger, and she is flanked by two columns with an unfinished-looking landscape in the background.
This, according to the foundation, corresponds with historical descriptions of an unfinished version of the Mona Lisa that featured columns, as well as early copies and sketches of da Vinci's famous painting by fellow Italian master Raphael, among others.
The painting, known as the "Isleworth Mona Lisa", was long owned by Henry Pulitzer. But an international consortium bought it from the estate of Pulitzer's late partner in 2008 for an undisclosed sum and asked the Mona Lisa Foundation to try to verify that it was the work of da Vinci.
The consortium members, presided over by art dealer David Feldman, remain anonymous, so it is unclear who would benefit from the portrait being attributed to da Vinci.
At Thursday's presentation, Frey would not estimate how much the portrait was worth or specify plans for the painting.
But he said he did not think it would be sold into private hands, insisting it should be accessible to the public.
The foundation gathered experts in Geneva to testify to the probability that the portrait was painted but left unfinished by da Vinci about a decade before he completed its famous "sister", now on display at the Louvre in Paris.
John Asmus, a professor at the University of California and a specialist in the digitalisation of artwork, said he was struck by "the same ideas about geometry that showed up" in both paintings.
"The ellipses in both paintings show a very complex interaction," he said, adding he "was greatly impressed by the loveliness of the figure".
Alessandro Vezzosi, director of the Leonardo da Vinci Museum in Vinci, Italy, and a world-renowned expert on the artist and the Mona Lisa, was more cautious.
He nonetheless whetted the appetites of the 100 journalists present for the occasion, describing the painting as "an important work of art."
He said the foundation's claim that the two paintings portray Lisa del Giocondo at two different moments of her life was "a fascinating possibility".
Joe Mullins, a forensic specialist trained at the FBI, described how he had been asked to "age regress" the original Mona Lisa to determine what she would have looked like 11 to 12 years earlier.
He described himself as a "digital plastic surgeon", giving the painting "a digital facelift and Botox".
Showing digital photographs of what Mona Lisa would have looked like, and then skimming away shadows and "the effects of gravity" for reporters, he said: "Everything lined up perfectly. Based on my experience... the facts and the images speak for themselves.
"This is 'Mona Lisa', two different images at two different times in her life."
But several experts not at Thursday's presentation said they suspected the Italian master had not painted an earlier version.
"The 'Isleworth Mona Lisa' mistranslates subtle details of the original, including the sitter's veil, her hair, the translucent layer of her dress, the structure of the hands. The landscape is devoid of atmospheric subtlety," Oxford University art historian Martin Kemp said in a statement.
"The head, like all other copies, does not capture the profound elusiveness of the original," he added.
Several other experts also voiced scepticism to AFP about the "earlier version" claim, but they refused to be cited.
Foundation representatives said Thursday the sceptics were welcome to take a closer look.
The Mona Lisa Foundation also released a 320-page book entitled "Mona Lisa -- Leonardo's Earlier Version", presenting evidence that da Vinci painted the work.