When it comes to the works of the great Leonardo da Vinci, separating his authenticated art from the "might be authentic" has never been easy. In 15th-century Italy the custom for artists was to collaborate in a workshop under a master's direction. Works were seldom signed.
The issue of authenticity was raised again as Boston's Museum of Science this month opened the only United States venue for a major touring exhibition, "Leonardo da Vinci: Scientist, Inventor, Artist."
Although some art historians say that at the turn of the century nearly 100 works were considered to be Leonardo's, experts conclude that only five have earned near unanimous agreement and another six are in doubt.
Two small sculptures and several paintings in the exhibition were questioned by experts in a Boston Globe article, though the labels in the exhibit identify the works as "attributed to," and include comments that Leonardo and his pupils may or may not have completed some of the work.
"I am completely satisfied with the labeling," says David Ellis, director and president of the Museum of Science. "We were aware of the questions, and we felt we addressed those in a way that was appropriate to this institution." Less than a third of the exhibit focuses on Leonardo's art, and the rest explores his extraordinary work as a scientist and inventor.
First shown in Malmo, Sweden, the exhibition has already been seen by more than a million people in six European cities. It is sponsored by the German automobile maker Mercedes-Benz and the International Watch Company (IWC) of Schaffhausen, Switzerland.
In Boston, the exhibition has been expanded by the museum to include a dazzling array of hands-on activities, experiments, computerized information, and a multimedia show that reveal the work of a man considered to be a prophetic genius, and the spark of the Renaissance. Twenty-five models, built from Leonardo's sketches and plans, can be operated throughout it.
A wide scope of works
What few experts dispute, and what the exhibition celebrates, is the scope of Leonardo's imagination and interests. From anatomy to architecture, from his quirky, left-handed, backward writing in his voluminous notebooks to his interest in how and why birds fly, this exhibit details a man with a blueprint for the future.
His inventive curiosity created an early form of bicycle, automobile, helicopter, military tank, steam-powered cannon, submarine, and parachute. Most of the drawings of these machines were done in his notebooks and were centuries ahead of the successful development of the inventions.
Not long after Leonardo's death in 1519, scholars and art historians began the debate over authenticity of nearly every work of art, notebook page, or sketch believed to have come from his extraordinary imagination. In the art world, where forgeries and the vagaries of attributions can cost huge sums of money, most experts defend skepticism as necessary.
The doubt stems from Leonardo's tendency to leave work unfinished. "Leonardo never finished anything because there was no end to what he was doing," says Carlo Pedretti, director of the Armand Hammer Center for Leonardo Studies at the University of California at Los Angeles, and official adviser for the exhibit.
James Ackerman, professor emeritus of art history at Harvard University in Cambridge, Mass., was acting as an advisor to the museum before he quit over the issue of labeling the works in the exhibition.
"I recommended at the last moment that the way to handle the paintings was to hang them," he says, "and make a little announcement that the attribution had come with the show, and the museum was obliged to retain them. If the museum showed the labels [as they were] it would be implicated in the misinformation."
The catalogue for the exhibit, written and edited by the Institute for Cultural Exchange of Tubingen, Germany, was considered by Mr. Ackerman to be too generous in attributions.
Continuing the centuries-old debate, Otto Letze, director of the institute and tour manager of the exhibit, says, "The pictures in the exhibit have been X-rayed and examined by Dr. Carlo Pedretti and his scholars and fully endorsed by European scientists."
One of the works in question is an unsigned small wax figure of horse. The label at the exhibition "attributes" it to Leonardo. The basis for the attribution is the characteristic swirls in the work, and a line from Leonardo's notebooks in reference to a project: "Have a small one made of wax."
Authenticity of a work of art from another century is determined several ways, but often remains inconclusive even with research and passionate defense by experts. Conservators understand the technology and technique of a work, and art historians judge a work by stylist and contextual means, such as understanding the culture in which the artist worked.
"All the different schools of thought about Leonardo have defended their positions over the years," says Mr. Letze, "but we never wanted to get [caught] in this kind of a battlefield. The exhibit was not conceived to be an art exhibit, but an interactive exhibit covering all of Leonardo's work and interests."
* The exhibit continues until Sept. 1. For information call: (617) 723-2500.