The cleaning was carried out by wetting the surface with water and using a Long Q switched laser with a pulse duration of 120n, 130mJ energy and fluence between 0.5-1 J / cm2 to avoid the fusion phenomena that occur at higher fluences. In many cases the treated surface showed a yellowish hue immediately after the irradiation due to oxidative and redeposition dynamics: this phenomenon was clearly minimized when the irradiation was assisted by an Argon jet. In any case, it should be emphasized that this yellowing can be totally eliminated by using a finger, or a brush or a pad soaked in water or other solvent.
SILVER ECCLESIASTICAL FURNISHINGS FROM THE BASILICA OF MARIA SS. DELLE GRAZIE
S. GIOVANNI VALDARNO (AR)
THE WORK
The furnishings come from the Basilica Maria SS. Delle Grazie in San Giovanni Valdarno (AR) and belong to an already semi-industrial production of the XVIII-XIX century.
THE PROBLEMS OF RESTORATION
The artifacts, composed of a silver-copper alloy, were in a quite good conservative situation but characterized by various phenomena of encrustation or only oxidation, sometimes homogeneous, in other cases diffuse and tenuous or strongly localized. A systematic study was conducted which highlighted the applicability and advantages of laser ablation applied to silver artefacts exposed in museum and / or urban environments.
THE LASER
Client: Opificio delle Pietre Dure – Florence
Restorer: Paolo Belluzzo
– P. Belluzzo et alii, Pulitura laser di manufatti in argento, in Kermes La rivista del restauro, fasc. speciale Pulitura laser di bronzi dorati e argenti, Nardini Editore, Firenze 2008.
– P. Belluzzo, Pulitura laser di manufatti in argento, in Atti APLAR 2, Ed. Il Prato 2008, pp 103-11.