Deposition in St. Mark's Basilica of Venice.

Atmospheric pollutants may cause damage to monuments and historical buildings. Besides air contaminants, soluble salts are also responsible for stone deterioration and decay in outdoor and indoor monuments. The problem of how to conserve works of arts thus requires a deep knowledge of contaminants' concentration and distribution inside buildings. In this work, water-soluble ions inside St. Mark's Basilica in Venice were studied, with the aim of understanding their principal source and distribution inside the building. With the aid of Fourier transform infrared spectroscopy and scanning electron microscopy analysis, the interaction between ions and surface's material was also investigated. Ion chromatographic analysis of depositions highlighted a large amount of "deteriorating agents" such as sulphates and chlorides. A possible source in the innermost area of the basilica has been found for formates and nitrates. On the contrary, a decrease of chloride, from the entrance to the innermost area, has been found, which indicates that the source is outside the building. It is emphasized that different contaminants behave differently on different material, and the effect of pollution inside churches and monuments is not easy to predict. Wood and brick seem to react differently than stone and mortar to the damaging action of salts and pollutants. The present work should be considered a useful tool for the future preservation of St. Mark's Basilica in Venice.

Chemical and statistical characterization of selected documents from the archives of the Palazzo Ducale (Venice, Italy).

Inks and paper are the main materials and components of library and archive collections. Since the beginning of paper and ink production empirical recipes have been followed, but in the 19th century with the transformation of Europe during the Industrial Revolution, the continent became the main leader for the discovery of new products and new industrial production processes. The aim of this study is to shed light on paper and ink production processes during this key historical period. In this study we have chosen some documents preserved in the archive of the Soprintendenza dei Beni Architettonici e Paesaggistici (B.A.P.) di Venezia e Laguna, held in the Palazzo Ducale (Ducal Palace) of Venice. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR), and inductively coupled plasma-mass spectrometry (ICP-MS) allowed us to obtain a qualitative and quantitative characterization of the organic and inorganic components in both paper and inks. Cluster analysis and principal component analysis (PCA) were employed for statistical analysis of the results.