The exhibition in the Archaeological Museum of Aiani includes sculptures and reliefs made of stone (mainly marble & limestone) from the archaeological site of Aiani. Before commencing the process of conserving these objects, the ultimate aim of which was to make them fit for public display, a great deal of thought was given to how best to conserve them since most of them were covered with thick deposits of dirt due to the long period of time they had remained buried in the ground and these deposits made it difficult to read the inscriptions and discern the surface details. Their removal, particularly in the case of objects intended to be placed on public display, is essential both for aesthetic reasons and for study purposes.
The Aiani Archaeological Museum laser cleaning project began with a preliminary phase at the IESL-FORTH labs in Crete, which involved a series of tests on marble fragments with similar crusts. These indicated the Q-switched Nd:YAG system (1064 nm, ns pulse-width) to meet the criteria for cleaning and give the best results. The laser system was subsequently moved to the Museum’s laboratories and placed in a restricted area. During the cleaning process the relevant safety and precaution rules were observed in order to ensure the safety of the conservators. The cleaning methodology was there fine-tuned and the operational parameters of the laser system (energy density, number of pulses etc.) were selected according to the type of encrustation that was due to be removed.
In this cleaning intervention we chose to preserve a thin layer of encrustation on every object in order to avoid any possibility of damaging the patina. Besides revealing the surface details, the laser cleaning also improved the aesthetic appearance of the objects by reducing the colour differences. It also indicated the type of material used in the manufacture of the object and in some cases enabled the material to be identified with that found in the local quarries.