FLORENCE, Italy - Restorers using ultra-violet rays have rediscovered rich original details of Giotto's paintings in the Peruzzi Chapel in Florence's Santa Croce church that have been hidden for centuries.

"We have uncovered a secret Giotto," said Isabella Lapi Ballerini, head of Florence's Opificio delle Pietre Dure, one of the world's most prestigious art restoration laboratories.

Last year, more than a dozen restorers and researchers began an ambitious project of "non-invasive diagnostics" to ascertain the condition of the 12-m-high chapel, which Giotto painted in about 1320.

During the project, which lasted four months, restorers working on three stories of steel scaffolding noted that while viewing the paintings under ultra-violet light, they were able see amazing details not visible to the naked eye.

"It was something really astonishing," said Cecilia Frosinini, coordinator of the project that studied the scenes in the lives of John the Baptist and John the Evangelist.

"We knew we could get some very interesting results from our scientific diagnostics but when we looked under ultra-violet light, all of a sudden all these very faint paintings that were ruined by old restorations took on a new life," she said, pointing to one scene while donning protective eye wear.

Giotto's paintings in the lance-shaped chapel are believed to have had a major influence on Michelangelo, who was born nearly 140 years after Giotto died and who painted the Sistine Chapel in the early 1500s.

Today's restorers are seeing the details Michelangelo saw when he admired the paintings by Giotto, considered one of the artists who sowed the seeds for the Italian Renaissance.

"The scenes are again three dimensional we were able to see all the chiaroscuro effects," she said.

The Peruzzi Chapel was immortalized in E M Forster's Room with a View, in the scene where the young Lucy Honeychurch is shown the Giottos by George Emerson, her future husband.

Commissioned by the noble Peruzzi family, it was whitewashed in the early 1700s to make way for a new chapel design.

But when restorers removed the white paint in 1840, they weren't exactly delicate.

The 19th century "restorers" painted the parts of the Giottos that had been damaged, adding their own brushstrokes to highlight what was no longer visible from the ground.

In 1958, a restoration removed what the 19th century restorers added, leaving what remained of the original Giottos and what visitors to the church see today with their naked eyes.

Giotto painted the Peruzzi Chapel towards the end of his life and some experts believe he was striving for a different effect than he achieved with the fresco technique, in which the painting is done while the plaster is still wet.

"It allowed him to obtain something more rich in terms of colors, of decorations," Frosinini said. "But over time, dry painting is very fragile." Even after the 1958 restoration removed the "non-Giotto" parts added by 19th century "restorers", the paintings were left faint and anemic, like a patient who had never fully healed.

But they come to life under ultra-violet light. In the scene where God is accepting John the Evangelist into heaven, the wrinkles in John's forehead, the threads of his beard, the whites of his eyes and God's welcoming gaze appear like fleeting but powerful visions.