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

DIOCLETIAN PALACE

PERISTYLE IN DIOCLETIAN PALACE IN SPLIT (HR)  

AUTHORITY RESPONSIBLE OF THE RESTORATION:  Croatian Restoration Center

HISTORY: The Diocletian Palace in Split, Croatia, was built by the Roman Emperor Diocletian at the turn of the fourth century AD.  The perystile is located in the central part of the palace and has been built using the calcareous stone extracted from Brazza Island nearby.

The main part of the calcareous stones constituting the peristyle were covered by a quite thick black crust (from 0.5 to 10 mm) made of gypsum and carbon.

LASER CLEANING METHODOLOGY:

For the preliminary experimental part a SFR laser (Short Free Running) with pulse duration of 50-100us was used. For thin crusts of 0.5 mm an energy of 400mJ and fluence of about 13 J/cm2 is sufficient for  the removal, while with crusts of 2 mm it is necessary to increase the energy up to 1600mJ with fluence of about 22 J/cm2. In any case the surface has been wetted with water before irradiation.
Given the good results, the laser cleaning has been extended throughout the peristyle.