Critics scoffed when computers were first enlisted to help restore Michelangelo's magnificent frescoes in the Sistine Chapel. What could an electronic filing system in some Vatican basement contribute to the painstaking, labor-intensive task of liberating one of the world's largest and most famous paintings from nearly 500 years of accumulated grime and murky glue? But the computer -- an Apollo workstation programmed to map every curve and crack down to the last millimeter -- proved so indispensable that it was installed 20 meters (65 ft.) above the ground, on the main scaffold, where it put a wealth of data about the frescoes at the master restorer's fingertips. Today man and machine labor side by side, only an arm's length from Michelangelo's original brushstrokes.
The Sistine Chapel project was a breakthrough that made believers of the skeptics. Even the Vatican's chief restorer, Gianluigi Colalucci, concedes that future computers will recall in an instant visual information that used to require years of research, including, he adds with a laugh, "the errors we are making now." But more important, the restoration marked the beginning of the Italian art establishment's love affair with technology. Nowadays, computers linked up to gamma-ray detectors, infrared cameras and thermographic sensors are turning up in art-restoration projects all across Italy, from the vast ruins of Pompeii to the crowded workshops of Venice. In tasks ranging from simple cataloging to advanced image processing, the new technology not only is making restoration more manageable but also is helping solve some of the oldest mysteries of art history.
In the past, technological advances in art have moved from the new world to the old, as when computer techniques developed by NASA to enhance satellite photos were adapted for use on the works of the old masters. That flow has, to some extent, been reversed. With a major portion of the world's ancient art treasures located inside its borders, Italy has become the capital of high- tech restoration. Experts from such citadels of art as the Louvre, the Getty Museum and the Metropolitan Museum of Art are making pilgrimages to Italy to see how it is done in Rome, not to mention Venice, Milan and Florence.
The technology that most fascinates visitors is a method for peering below the surface of a finished artwork and analyzing the various layers of paint it contains. The technique, computerized infrared reflectoscopy, is based on the fact that some pigments that reflect light in the visible range (like cadmium red) are more or less transparent to infrared light. By looking through these layers, art historians can catch glimpses of the artist's original handiwork: rough sketches, repaintings and the occasional erasure. Other techniques, notably X-ray analysis, had been used in the past. The major advantage of using a computer with a video display screen is that the artwork can be superimposed over the infrared image, making the slightest differences easily visible.