The Conservation Intervention on the Porta della Mandorla

Abstract

We investigated the conservation problems of the Porta della Mandorla, a masterpiece of the early Florentine Renaissance. The aim of the work was the statement of practicable cleaning protocols based on laser ablation. To this goal, a thorough petrographic characterisation of the state of conservation was performed, which addressed a set of laser cleaning tests by Q-switching and short free running Nd:YAG lasers. The main optimisation problem was the yellow-orange appearance associated with laser ablation by Q-switching lasers. Following the explanation of such a cleaning result, two practicable solutions based on suitable pulse duration or wavelength selections were successfully demonstrated then different intervention protocols were proposed.