A Raman spectroscopic and combined analytical approach to the restoration of severely damaged frescoes: the Palomino project

Abstract

The deterioration of art objects is normally relatively minor, controllable and attributable to environmental changes or bacterial invasion, and until now there has not been any recorded attempt to analyse an artwork that has been deliberately and significantly destroyed. The analytical problems are correspondingly larger but the potential reward from any information that can be forthcoming is thereby proportionately greater. The 17th Century Palomino frescoes on the vaulted ceiling of the Church of Sant Joan del Mercat in Valencia were largely destroyed by insurgents in the Spanish Civil War in 1936. The ensuing gunfire and a series of seven conflagrations inside the church had a devastating effect upon the artwork, and the surviving areas were also rendered unstable with respect to their detachment from the substrate. During the current restoration project being undertaken on these frescoes, an opportunity was provided for the application of several analytical techniques to secure information about the original pigment palette employed, the technology of application used by Palomino and the changes consequent upon the destruction process. Here, we report for the first time the use of analytical Raman spectroscopy, supported by scanning electron microscopy (SEM) and voltammetry of microparticles, for the combined identification of pigments, binders, substrate treatments and pigment alteration in an important, although badly damaged, wall painting for the informing of the ongoing conservation and restoration strategy.

Recent advances in linear and non‐linear Raman spectroscopy. Part III

“…Differences between ancient and modern mortars are found. A Raman characterisation of painted mortar in Republican Raman mosaics was reported by Boschetti et al [43] A Raman spectroscopic and combined analytical (scanning electron microscopy and voltammetry of microparticles) approach to analyse the restoration of severely damaged 17th century Palomino frescoes on the vaulted ceiling of the Church of Sant Joan del Mercat in Valencia, Spain, was published by Edwards et al [44] Prinsloo et al [45] reported on the first Raman spectroscopic study of San rock art in the Ukhahlamba Drakensberg Park, South Africa. The authors have shown that Raman spectroscopy can play a very useful role in unravelling the key factors that contribute to the complex mechanism of weathering of the rock faces depicting San rock art.…”

An authentication case study: Antonio Palomino versus Vicente Guillo paintings in the vaulted ceiling of the Sant Joan del Mercat church (Valencia, Spain)

“…During this period, seven fires were lit in the church in an attempt to destroy the frescoes. Thus, the recognition of unusual alteration products formed from the pigments, as well as from substrate and ground layers, has been another important aim of the scientific study carried out on the frescoes at Sant Joan del Mercat along with the analytical identification of pigments and painting materials, a problem that has been partially solved in prior works …”

A detailed micro‐Raman spectroscopic study of wall paintings of the period AD 100–200: effect of atmospheric conditions on the alteration of samples

“…This question has been the subject of several scientific studies on the alteration of wall paintings and frescoes. [6,13,14] Pérez-Alonso et al have observed extensive damage in frescoes in the church of Santa Maria, located in the Monasterio de Hermo, Asturas. Visual and spectroscopic examinations were used to identify the percolation and upward migration of salts as the initial cause of damage, the nitrates of the salts being probably the migrant species from the old cemetery.…”