TECHNOLOGICAL ANSWERS
TO RESTORATION

The growing need to preserve our cultural heritage is causing a rise in the demand for increasingly accurate cleaning techniques, featuring high selectivity and low impact.

CASI DI STUDIO

THE GATES OF PARADISE

THE GATES OF PARADISE OF FLORENCE BAPTISTERY – LORENZO GHIBERTI

AUTHORITY RESPONSIBLE OF THE RESTORATION: Opificio delle Pietre Dure - Florence

 

RESTORER:  Annalena Brini, Stefania Agnoletti, Nicola Salvioli

 

History:

The Gates of Paradise are the east doors of the baptistery of Florence, facing the cathedral of Santa Maria del Fiore. Made by the goldsmith and sculptor Lorenzo Ghiberti between 1425 and 1452, the gates represent his masterpiece as well as one of the most significant works of art of the Florentine Renaissance. In gilded massive bronze, the doors were nicknamed “of Paradise” by Michelangelo Buonarroti. Since the great flood of 1966, and after a thorough restoration lasted 27 years, the doors are now kept in a special clear case in the nearby Museo dell'Opera del Duomo (Museum of the Works of the Cathedral).

LASER CLEANING METHOD:

Initially, it was decided to remove the panels from their bronze frame, and subject them to an optimized chemical methodology.  Unfortunately, the removal of the panels proved too risky, and alternative cleaning techniques were investigated, among which leaser cleaning. The gilded surface was scattered with tiny blisters originated from the crystallization of soluble salts under the gold foil. The latter had peeled off and fallen off due to the breaking of the blisters or to abrasion. The sectional investigation had shown three main layers over the bronze layer: the incrustation, the gold foil, and the cuprite. A laser with 100ns pulse (Long Q- Switching, EOS 1000 LQS system) was successfully used to clear the decoration. The duration of the pulse avoided any possible side effect on the gold foil: the latter was protected all over, and the complete removal of the surface incrustation revealed the brightness of the gold.

ADOPTED SYSTEM