UTILIZZO DI TELI IMPERMEABILI ALLA LUCE PER LA RIDUZIONE DI PATINE BIOLOGICHE VERDI SU MANUFATTI LAPIDEI ESPOSTI ALL’ESTERNO

Roberta Gasperini1, Marco Mozzato2, Marco Rebesan3, Simona Vuerich4

1,2,3,4Accademia di Belle Arti di Verona, via Montanari, 5-37122 Verona, 1rgasperini@fastwebnet.it, 4simonavuerich@hotmail.com

ABSTRACT

This study was carried out in order to evaluate the efficacy of impervious to light cover systems in reducing the biological colonization on stone artifacts exposed under outdoor conditions. The research has been conducted on three calcareous stone sculptures located in Querini Park (Vicenza, Italy) for a period of 3 months, from the 22nd of October 2012 to the 1st of February 2013. The deterioration degree was similar for all artifacts and was due to green algae forming biological patinas. Two of the stone artifacts have been entirely wrapped with black waterproof transpirable covers, refractory to light, while the third one was left uncovered to keep it as positive control. Regular assessments have been performed to measure light intensity, outside and under the covers, temperature and relative humidity; samples have been also collected to determine cell viability. For the covered artifacts following results were obtained: stabilization of the environmental parameters under the covers, dehydration of the biological patinas and modification of algae’s colour, reduction of the colonization consistency and adhesion to stone. These algal patinas, in contrast to those grown on the uncovered monument, could be easily removed with a dry brush, without using any chemical substances or water. These encouraging results suggest that further research should be done, in order to possibly define and apply this method as conservation treatment.

Parole chiave/Key-words: outdoor stone artifacts, biological patina, refractory to light covers, waterproof transpirable material, conservation treatment