Mona Lisa replicas and reinterpretations
After restoration, the Prado's "Mona Lisa" revealed details covered by previous restorations and layers of varnish.
Furnishings and fabrics were enhanced, as well as landscape and facial features.
It is anticipated that such revelations may offer further insight into Leonardo's original.
Experts at the Louvre reportedly supported the Prado museum's findings.
The Prado replica was subsequently transported to the Louvre in 2012 to be displayed next to "Mona Lisa" as part of a temporary exhibition.
Two nude paintings bearing similarities to Leonardo da Vinci's original were part of a 2009 exhibition of artwork inspired by "Mona Lisa".
Displayed at the Museo Ideale in Leonardo's hometown of Vinci, near Florence, some believe one of the paintings – dating from Leonardo's time – to be the work of Leonardo himself, and it has at times been credited to him.
Other experts theorize the painting, one of at least six known to exist, may be just another copy painted by "followers" of Leonardo.
Scholarly dispute persists as to artist, subject and origin.
The nude in question, discovered behind a wall in a private library, reportedly belonged to an uncle of Napoleon Bonaparte, who owned another of Leonardo's paintings.
Facial features bear only vague resemblance, but landscape, compositional and technical details correspond to those of the "Mona Lisa" known worldwide today.
Speculations about Mona Lisa
In 2004, experts from the National Research Council of Canada conducted a three-dimensional infrared scan. Because of the aging of the varnish on the painting it is difficult to discern details. Data from the scan and infrared were used by Bruno Mottin of the French Museums' "Center for Research and Restoration" to argue that the transparent gauze veil worn by the sitter is a guarnello, typically used by women while pregnant or just after giving birth. A similar guarnello was painted by Sandro Botticelli in his "Portrait of Smeralda Brandini" (c. 1470/1475), depicting a pregnant woman on display in the Victoria and Albert Museum in London. Furthermore, this reflectography revealed that "Mona Lisa"'s hair is not loosely hanging down, but seems attached at the back of the head to a bonnet or pinned back into a chignon and covered with a veil, bordered with a sombre rolled hem. In the 16th century, hair hanging loosely down on the shoulders was the customary style of unmarried young women or prostitutes. This apparent contradiction with her status as a married woman has now been resolved.