The cleaning intervention on the Acropolis monument sculptures, is taking place within the framework of an innovative project for the restoration of the architectural masterpieces of Pentelic marble. The selected and controlled removal of soot deposits and black encrustations from the surface of archaeological material was realised by means of a novel laser cleaning methodology specially designed for the specific needs of these sculptures.
The two prototype laser cleaning systems, currently operating on the Acropolis Monuments, were designed by the IESL-FORTH, in collaboration with the Acropolis Restoration Service and the A’ Ephorate of Prehistoric and Classical Antiquities. The success of this innovative cleaning methodology lies in the combination of infrared (1064 nm) and ultraviolet (355 nm) radiation. The project involved a thorough and detailed comparative study of all existing cleaning techniques, followed by trials on selected sections of the Acropolis monuments and Museum sculptures.
The first assemblage from the Acropolis to benefit from the laser cleaning methodology was the West Frieze of the Parthenon (2002-2005). This cleaning process has enabled the restoration of the aesthetic value of the sculptures while revealing ancient monochromatic surface layers, as well as other historic valuable information, such as tool mark traces that have survived on the surface of sculptures.
Currently two prototype laser cleaning systems are operating on the Acropolis Monuments in Athens:
a) One is located inside the new Acropolis Museum and is used to remove unwanted encrustation from the Acropolis monument sculptures, now on display in this museum. More specifically, the laser cleaning methodology has been employed for the cleaning of the sculptures from the Parthenon, the Erechtheion and the Temple of Athena Nike. A total of seventeen metopes from the north and east sides of the Parthenon have been restored, along with four pedimental sculptures (the Kekrops and Pandrosos group and the horses of Helios and Selene). Further restoration has been carried out on the upper body of Caryatid F and on four blocks from the Frieze of the Temple of Athena Nike (2006-2010).
The project continues in 2011 with the cleaning of the Caryatids (A, B, D and E). For this purpose an advanced laser laboratory has been recently set up on the visitors’ floor where the Caryatids are exhibited at the Acropolis Museum. Removal of pollution accumulations from their surface takes place in this laboratory. This arrangement brings the visitors of the Acropolis Museum in contact with the conservation interventions that until now took place only inside restricted access laboratory environments. This exhibits a symbolic connection between ancient and modern Greece.
b) The other is located inside the Caryatids’ porch in the Erechtheion with the aim to clean the roof of the porch. This is a complicated project because, besides pollution, restorers must erase soot from fires and the mistakes of past restorers who tried to mend the roof with unconventional materials (i.e. cement).