In-situ technical study of modern paintings - Part 2: Imaging and spectroscopic analysis of zinc white in paintings from 1889 to 1940 by Alessandro Milesi (1856-1945)

A Critical Review on the Analysis of Metal Soaps in Oil Paintings

Up to 70 % of the oil paintings conserved in collections present metal soaps, which result from the chemical reaction between metal ions present in the painted layers and free fatty acids from the lipidic binders. In recent decades, conservators and conservation scientists have been systematically identifying various and frequent conservation problems that can be linked to the formation of metal soaps. It is also increasingly recognized that metal soap formation may not compromise the integrity of paint so there is a need for careful assessment of the implications of metal soaps for conservation. This review aims to critically assess scientific literature related to commonly adopted analytical techniques for the analysis of metal soaps in oil paintings. A comparison of different analytical methods is provided, highlighting advantages associated with each, as well as limitations identified through the analysis of reference materials and applications to the analysis of samples from historical paintings.

Investigating counterfeiting of an artwork by XRF, SEM-EDS, FTIR and synchrotron radiation induced MA-XRF at LNLS-BRAZIL

In this work, a painting suspected of counterfeiting was analyzed using the synchrotron-based scanning macro X-ray fluorescence (MA-XRF) technique. The canvas has erasures including a signature erasure; however, some visible numbers indicate that the artwork may be from the 17th century. Through the studies' elemental maps, Cl-K and Ca-K were observed, which allowed us to reconstruct the signature present in the painting. Elemental maps of Ba-K, Ti-K, Fe-K, Zn-K, and Pb-K were also obtained from the painting, which made possible to visualize how the pigments based on these elements were used in the creative composition of the painting. In addition to the signature region, a region of the painting with dimensions of approximately 120 mm × 120 mm was investigated by synchrotron radiation induced MA-XRF, while keeping a high spatial resolution and elemental sensitivity. The measurements were carried out at the D09B micro-XRF beamline of the Brazilian Synchrotron Light Laboratory (LNLS), part of the Brazilian Center of Research in Energy and Materials, in Campinas Brazil. The painting was also investigated by SEM-EDS, and FTIR techniques. Those results, in addition to the supporting elemental maps, allowed additional information to be obtained, such as the binders used on the painting.

Investigation of modern oil paints through a physico-chemical integrated approach. Emblematic cases from Valencia, Spain

The study and the characterisation of modern and contemporary oil paintings is still a challenging issue, in particular considering the significant changes in paint production across the 19th and 20th centuries. This paper presents the results of the first physico-chemical integrated study of the artistic materials used in six paintings from the School of Art and Higher Design of Valencia (Escola d'Art i Superior de Disseny, EASD-Valencia), artworks created between 1871 and 1943 by four famous Valencian artists: Salustiano Asenso Arozarena, Salvador Abril I Blasco, Enrique Navas Escuriet and José Bellver Delmás. A wide range of inorganic and organic compounds was identified through a multi-analytical approach by means of visible reflectance spectroscopy, XRF, μ-Raman, FTIR and GC-MS. The investigation on the binding media suggests the use of commercial paint formulations including mixtures of drying, slow- and non-drying oils and the presence of Gum Arabic as well. Traditional pigments (such as vermillion, earth pigments, lead white) and modern pigments (such as zinc white, cobalt and chromium-based pigments) were identified together with fillers and extenders. Degradation products, in particular zinc and lead soaps having strong conservation implications, were also detected. This work, focusing on the identification of the palettes and the binding media used by the selected artists, aims at providing meaningful data and interesting case studies that are useful beyond the Valencian painters solely. This study provides new insight into the use of 19th-20th century commercial oil paints and the selection of painters' palette and their artistic production techniques. Besides, this work highlights the necessity of a multi-analytical approach to obtain valuable information for documentation and preventive conservation.

The Noninvasive Analysis of Paint Mixtures on Canvas Using an EPR MOUSE

Many artists create the variety of colors in their paintings by mixing a small number of primary pigments. Therefore, analytical techniques for studying paintings must be capable of determining the components of mixtures. Electron paramagnetic resonance (EPR) spectroscopy is one of many techniques that can achieve this, however it is invasive. With the recent introduction of the EPR mobile universal surface explorer (MOUSE), EPR is no longer invasive. The EPR MOUSE and a least squares regression algorithm were used to noninvasively identify pairwise mixtures of seven different paramagnetic pigments in paint on canvas. This capability will help art conservators, historians, and restorers to study paintings with EPR spectroscopy.

How Many Secret Details Could a Systematic Multi-Analytical Study Reveal About the Mysterious Fresco Trionfo della Morte?

The “Trionfo della morte” is a detached fresco painting dated at the half of the XV century. Its history is strictly connected with the history of Palermo and it is considered a symbol of the late Gothic period. Some small areas of the fresco were analyzed using a combination of non-invasive techniques and hand-held instrumentations (multispectral imaging analysis, X-ray fluorescence (XRF), and IR spectroscopy). The characterization of the nature of pigments used in its realization and restoration works was performed and some indications about its conservation state were obtained. More interestingly, some hidden details were revealed on the mysterious painting. They constitute additional evidence of the preciousness of the fresco.