Verifica dello stato di conservazione di monumenti ferraresi dopo alcuni decenni dagli interventi di restauro

Some monuments of Ferrara were submitted to restoration carried out over a period from 20 to 10 years ago. About 20 and 10 years later, in some cases macroscopic deteriorations were detected: abundant biological growth, detachment of stone fragments, colour changes of areas treated with organic substances in respect to untreated areas. The purpose of this paper is the control of the presence, after about 20 years, of some substances used in the restoration as well as their potential for biological growth.