Characterization of Soluble Salts on the Frescoes by Saturnino Gatti in the Church of San Panfilo in Villagrande di Tornimparte (L’Aquila)

Abstract

Salt crystallization is one of the most dangerous forms of degradation affecting frescoes. This phenomenon can lead to cracking, flaking and detachment of the pictorial layer, ultimately ruining the work of art. However, the characterization of soluble salts via chemical analysis can be employed to determine the conditions of the artifact and establish the proper restoration and/or conservation strategies to be adopted. In this archaeometric study, a first-ever characterization of the soluble salts and related degradation phenomena on the frescoes by Saturnino Gatti in the church of San Panfilo in Villagrande di Tornimparte (L’Aquila) was carried out. Sampling was performed in areas with evident detachments, exfoliations and saline crystallization (efflorescences). Eleven samples of powder and fragments were taken from different panels of the fresco: nine were taken from Panels A, C, D and E and two from the top part of the vault. Chemical characterizations were performed using two analytical techniques: ion chromatography (IC) and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). Ion chromatography was used for the quantification of the main ions and to evaluate the presence of soluble salts, whereas infrared spectroscopy was used to characterize the mineralogical phases. The results show efflorescence consisting of newly formed gypsum and carbonate in samples taken closer to the ground. Furthermore, a good correlation between sodium and chloride ions was observed, indicating the presence of an efflorescence composed of newly formed sodium chloride. Capillary rise and infiltration were highlighted as the main sources of soluble salts. This information will be crucial in guiding future restoration or conservation operations.

Identifying Original and Restoration Materials through Spectroscopic Analyses on Saturnino Gatti Mural Paintings: How Far a Noninvasive Approach Can Go

“…Indeed, sub-efflorescence and efflorescence, with consequent detachment and disintegration, were observed on the restoration mortars near the windows of panels A and C and along the lower part of the apsidal conch [34]. It is also worth noting that calcium sulfate was also detected in the samples from the Saturnino Gatti cycle through micro-stratigraphic analyses of thin sections [35] and the characterization of sampled soluble salts [36]. Reference spectra [22] were also reported for comparison.…”

Special Issue: Results of the II National Research Project of AIAr: Archaeometric Study of the Frescoes by Saturnino Gatti and Workshop at the Church of San Panfilo in Tornimparte (AQ, Italy)

“…The complete analysis of the frescoes' state of conservation revealed several areas of detachment or degradation phenomena. Thanks to the use of two analytical techniques (IC and ATR-FTIR) performed on micro-samples [23], it was possible to characterize the degradation due to salt crystallization. Specifically, efflorescence was mainly caused by newly formed crystals of gypsum and calcium carbonate, mainly due to the capillary rise from the ground, with the exception of the samples taken close to the window splays and from the vault, in which infiltration could be responsible.…”

An Assessment of the Natural Radioactivity Content in Pigments and an Estimation of the Radiological Health Risk for the Public

“…In the case of natural minerals and earths with coloring effects, namely iron and manganese oxides and hydroxides, a complete overview has already been provided [4][5][6][7][8]. In particular, the presence of pigment pieces of various sizes, pigment powders, and residues, and even paint drops in deposits, like seashells, stone and brick utensils, millstones, vessels of different kinds, and so forth, is well documented [9][10][11].…”