Painting technique and state of conservation of wall paintings at Qusayr Amra,Amman – Jordan

The state of conservation of the frescoes at Qusayr Amra was investigated by integrated physico-chemical measurements, particularly optical and scanning electron microscopy, μ-infrared spectroscopy, mass spectrometry and X-ray powder diffraction.The frescoes appear darkened and severely damaged owing to the deterioration of surface treatments and to the widespread presence of different salts. These caused significant detachments of the painting layers.The materials used in the painting and preparation layers and in the wall plaster were characterized in order to clarify the painting technique. Different pigments have been identified on the pictorial layers: the original ones correspond to green earth, yellow and red ochre, realgar, bone black and lapis lazuli and others, such as titanium white and cobalt blue, ascribed to recent restoration works. Proteinaceous materials (egg or yolk) have been identified as binders for the pigments, indicating a tempera painting technique.Three different products, belonging to restoration interventions, have been also identified: the natural product shellac, ascribable to next-to-last restoration and scarcely removed during last restoration also because of its insolubility, the synthetic vinyl acetate and acrylic polymers. Particularly the latter one indicates an on-going degradation of the applied fixatives.The extensive deterioration of the surfaces is also due to the widespread presence of salts, such as chloride, nitrate and sulphate clearly identified by XRD measurements.The obtained results give a comprehensive overview on the employed painting technique and its state of preservation and on the causes of the painting deterioration. Therefore, they are a fundamental tool to develop durable and compatible materials and methodologies for a future conservation strategy of this site.     

Pigment identification in a Greek icon by optical microscopy and infrared microspectroscopy

Optical microscopy, cross-section and fragment Micro-FTIR spectroscopic techniques along with microchemical tests were used for the identification of pigments in two different samples of an icon. Representing the Last Judgement, and painted by the Greek master Ioannis from the village of Kapesovo in the year 1771, the kneeling desk icon under investigation is a noteworthy contribution to the study of materials in post-Byzantine visual arts. The main components found in the ground layer of both samples were gypsum, beeswax and a proteinaceous material. Cinnabar, Prussian blue and cerussite were identified on the paint layers. The binding medium on the paint layers was weddelite. The materials used in the painting and ground layers were characterized in order to clarify the painting technique. Proteinaceous materials have been identified as binders for the pigments, indicating a tempera painting technique.     

The scientific approach to the restoration and monitoring of mural paintings at S. Girolamo Chapel – SS. Annunziata Church in Florence

The scientific approach to the restoration and monitoring of mural paintings, at S. Girolamo Chapel – SS. Annunziata Church in Florence, is reported as a fruitful example of the synergic collaboration between restorers and scientists in the planning and development of conservative interventions. Before restoration, the painting technique and the state of preservation of the pictorial cycle have been investigated firstly by close examination of the painted surfaces and then by optical and/or SEM-EDS microscopy and μFT-IR spectroscopy on appropriately selected samples. In particular, the original constituent materials and those belonging to subsequent restorations were characterized together with those originating from decay processes. In this mural painting cycle, a peculiar “fresco” technique has been used although an auxiliary binder for pigment distemper has been also employed. The use of this technique, sometimes in an improper way together with uncorrected restoration interventions, are the main responsible of the unsatisfactory state of conservation of many painted areas. Preliminary conservation trials and scientific studies were carried out to design the most convenient restoration intervention and to verify the correctness and non-invasive of the necessary operations. Special attention was devoted to cleaning procedures, continuously monitored by a physico-chemical methodology, mainly based on microinvasive, microscopic and spectroscopic investigations, to evaluate the efficiency, advantages and drawbacks of the proposed cleaning procedures and define the most appropriate ones. Finally, specific decay markers have been recognized, by a comparison of the results obtained from the detached samples with those deriving from artificially aged models, to be used for a correct future monitoring and maintenance of the wall paintings.     

An analytical investigation of the painting technique of Italian Renaissance master Lorenzo Lotto

This paper presents the first extensive investigation of the composition of both the organic and inorganic media used by Lorenzo Lotto, one of the outstanding artists of the Italian Renaissance in the early 16th century. By investigating four paintings from The State Hermitage Museum collection (Saint-Petersburg, Russia), new insights into the artist's painting techniques were obtained, which contribute to our understanding of the transition from egg tempera to oil painting techniques that took place in Italian paintings between the 15th to the mid 16th century. Inorganic materials were determined using SEM-EDX and PLM, revealing information on the artist's palette. Of particular note was the powdered colourless glass found in the priming layer of the Madonna delle Grazie, which was most likely used as dryer. Organic materials were analysed in individual paint layers using GC-MS, and revealed a mature use of drying oils as paint binders, skilfully mixed with other organic materials and inorganic driers, to obtain the desired aesthetical and technical qualities of the paint. The study revealed that Lotto used the tempera grassa technique through most of his creative life.     

Pigments and binders in “Madonna col Bambino e S. Giovannino” by Botticelli investigated by micro-Raman and GC/MS

During the restoration plan of the famous painting “Madonna col Bambino e S. Giovannino” by Sandro Botticelli, located in the Museo Civico of Piacenza (Italy), a study on painting materials was carried out. The pigments, the binders and the materials used for the application of ground and priming layers were studied using micro-Raman spectroscopy, gas chromatography coupled with mass spectrometry (GC/MS), optical and electronic microscopies. Gypsum and anhydrite were found in the ground layer, while carbon black and lead white were used in the priming layers. The precious pigments of the artist's palette and the binders used (egg and animal glue) were determined.     

The case study of an Italian contemporary art object: Materials and state of conservation of the painting “Ragazzo seduto” by Remo Brindisi

This paper deals with the scientific survey of Remo Brindisi's painting “Ragazzo seduto” (Seated boy), made at the end of the 1950s, that is a symbolic figure of both his personal artistic solitude and the crisis of values determined by the economic boom in the post-war period. In a period of great changes and economic regrowth, the need to find a new style that could be the most authentic and personal as possible pressed the artist to experiment innovative products, including non-conventional support. Photographic and analytical techniques demonstrated the use of innovative products as an experimentation tendency, that pressed the artist to use non-conventional support, industrially treated with plasticized PVC and primed with acrylate polymers and to paint with traditional and industrial pigments mixed with an oil-modified alkyd resin. In the span of a few years, an unexpected and extended degradation on the whole surface of the painting took place, with the consequent formation of lifting and detachment of the paint film. The detected alteration is mainly due to the fast ageing of the employed polymeric materials, actually responsible of the impermanence of many contemporary works of arts. Clarifying the unknown aspects of the Remo Brindisi's stylistic choices together with the deterioration processes of the employed painting materials, this paper highlights the general problems related to the conservation of contemporary art, a neglected area of research in Italy, where more efforts are committed to the enormous and more ancient cultural heritage.     

Spectroscopic and chromatographic studies of sculptural polychromy in the Zhongshan Grottoes (R.P.C.)

The sculptural polychromy in the Zhongshan Grottoes, sited in northwest China, has been investigated in terms of chemical composition of employed materials and pigments, state of conservation and painting technique. Raman analysis, Fourier-transform infrared analysis, analysis through energy-dispersive X-ray spectrometry coupled to scanning electron microscopy and pyrolysis coupled to gas chromatography and mass spectrometry were applied. Six analyzed samples showed silicates and kaolin as main components of the ground layers. Also lead white has been found in these layers. Minium, red-earth and mercury sulfide are the red pigments detected in the polychromy. A mixed use of malachite and atacamite has been detected in three green samples. Optical characteristics of atacamite and malachite found in the samples indicate a synthetic origin. The presence of a synthetic organic pigment such as phthalocyanine chlorinated pigment was also revealed. Ultramarine blue pigment, obtained by purification of lapis lazuli, has been detected in the blue sample. As for the binders used, fatty materials and siccative oil were found.     

La Medusa by Caravaggio: characterisation of the painting technique and evaluation of the state of conservation

The oil painting “La Medusa” executed by Caravaggio at the end of the XVI century on a wooden shield, was investigated by integrated physical–chemical and analytical methodologies in order to obtain scientific data capable of elucidating the state of conservation and the painting technique. Optical (OM) and electronic (SEM-EDS) microscopy, micro-FT-IR spectroscopy, gas chromatography–mass spectrometry (GC–MS) and pyrolysis GC–MS were applied on two microfragments and some organic samples obtained by solvent extraction using the swab cleaning technique. The obtained results indicated that Caravaggio probably reused an old shield as a previous gypsum preparation layer has been detected under the original painting layers. He used white lead, natural earths, verdigris and lead–tin yellow type I mixed with drying oils to paint. The considerable amount of amorphous particles of copper chlorides found in the green pigment verdigris suggests that it could have been produced according to the ancient recipe of verde salsum described by Theophilus. Mordant gilding has been identified on the upper part of the shield that can be related to an abandoned experiment to give the painting a mirror-like reflecting effect. Three different varnishes layers have been detected above the painted surface. The original and restoration varnishes have been identified and they contain a mixture of drying oil, mastic and turpentine and some beeswax. Cleaning tests, performed with different organic solvents, suggest the use of isopropyl alcohol as cleaning agent because it is less efficient in comparison to others solvents; thus it ensures a careful and controlled removal of the varnishes.     

Teodelinda's tales at Monza Cathedral: A physico-chemical diagnosis of the pictorial cycle

The pictorial cycle “Teodelinda's Tales” at Monza Cathedral, painted by Zavattari and his sons in 1444–1446, has been investigated by optical and SEM-EDS microscopy and microFT-IR spectroscopy. Paint layers, gildings and other metallic decorations have been analysed to elucidate the execution technique, the state of conservation and the possible retouchings in consequence of deterioration processes. Organic binders, coatings and adhesives have been also identified especially by microFT-IR spectroscopy applied directly to the sampled powders or fragments and to their solvent–soluble fractions. The obtained data offer a correct and satisfactory knowledge of the original organic and inorganic materials and those used in the subsequent retouches and restorations, their state of conservation and the painting techniques (fresco, mezzo fresco and secco).The physico-chemical investigations allowed to identify the nature and sometimes the provenance of the employed materials (i.e. ultramarine blue pigments) and some decay markers, particularly useful in understanding and describing the cycle realised by the authors and the modifications suffered along the centuries, and also to propose an integrated methodology for the scientific study of the mural paintings.     

The funerary klinai of tomb 1 from Amphipolis and a sarcophagus from ancient Tragilos, eastern Macedonia: a physico-chemical investigation on the painting materials

Optical and SEM-EDS microscopy, X-ray powder diffraction and micro FT-IR spectroscopy investigations of the funerary klinai (couches) of Tomb 1 from Amphipolis and a stone sarcophagus from ancient Tragilos—two painted monuments made by Macedonian craftsmen of the Early Hellenistic period—identified the original materials and painting technique, as well as synthetic materials used as consolidants during past restoration treatments. The original organic binders and the superficial modern coatings have been identified by micro FT-IR spectroscopy applied directly to the sampled powders or tiny fragments and to their solvent—soluble fractions. The pigments identified on the couch of Amphipolis are: red and yellow ochre, cinnabar, Madder lake, paratacamite and antlerite, carbon black, calcium carbonate, kaolin and gypsum. The identification of egg and animal glue confirms the application of tempera and secco techniques. The detection of polymers such as polydimethylsiloxane, polyvinyl acetate and alkyd resins, is related to modern restoration products. The pigments attested on the paintings of the Tragilos' sarcophagus are: red and yellow ochre, Egyptian blue, malachite, carbon black, calcium carbonate and gypsum. The absence of organic binders combined with the constant presence of calcium carbonate in all the examined samples suggests the use of lime as the binding medium in the painted decoration of the sarcophagus. The presence of Paraloid B72 is related to recent conservation treatments.     

Raman mapping analysis of pigments from Proas Iluminadas by Quinquela Martín

The painting Proas Iluminadas (Illuminated Bows) by Benito Quinquela Martín is studied by Raman spectroscopy in order to analyse the technique and the pigments employed by the artist: ultramarine blue, carbon black, cadmium-sulphure based compounds for the hue of yellow, orange and red; also zinc white, barium yellow, massicot yellow and viridian were observed. The importance of using different excitation laser lines in the analysis of mixtures of pigments is highlighted. The Raman mapping analysis of cross section samples shows the way the artist composed the ground layer: a lead white stratum over a calcite one. It also allows distinguishing between a mixture of components and strata superposition, both presenting the same appearance under an optical microscope. This paper provides information about the materials and techniques used in a period of Argentine art not studied before from this point of view.     

Protein identification and localization using mass spectrometry and staining tests in cross-sections of polychrome samples

The identification and localization of the proteinaceous binders are essential issues in studies of painting materials and techniques, for further proposing valid restoration and conservation treatments of the painted or polychrome works of art. The challenge for analytical chemists and conservation scientists is the availability of methods able to simultaneously identify and map the presence of the binders in the multilayered structure of a sample and the possibility to use a very low amount of sample from the studied art object (considering also the criteria of minimum sampling). These methods should be fast, reproducible in different artefacts and in case of mixture of protein-based binders with other non-proteinaceous constituents (oils, resins, waxes, gums etc.) and also economical (both in terms of materials and time consume). In this context, the present paper proposes an innovative protocol of investigation using two complementary techniques – Matrix-Assisted Laser Desorption/Ionisation – Time of Flight Mass Spectrometry (MALDI-TOF MS) and staining tests (one visible and one fluorescent stain) assisted by Optical Microscopy (OM) on cross-section of samples – for the simultaneous identification and mapping of protein – and oil-based binders in paint materials. The novelty is based on the use of MALDI-TOF MS on cross-sections of paints together with a fluorescent stain for protein identification and mapping (mainly used in the area of proteomics) complementing the use of a traditional visible stain for oil-based material identification. The protocol was successfully applied on several samples taken from a Czech medieval polychrome sculpture, entitled “The Mourning of Jesus Christ” (16th century) belonging to the Moravian Gallery (Brno).     

Transylvanian glass icons: A GC/MS study on the binding media

Transylvanian glass icons are very specific heritage items of Romanian folk art, produced from the middle of 18th century until now. The present research reports the results of a study on the organic components of the paint layers, analyzing the binding media of a series of glass icons belonging to three important icon making centers: Nicula, Olt County (?ara Oltului) and Brasov area (?cheii Bra?ovului). The analysis of the binding media has been done by means of gas chromatography coupled with mass spectrometry (GC/MS). The applied analytical procedure allowed the characterization of the proteinaceous, polysaccharide and lipid-resinous content of the binding media starting from a unique microsample. Results showed that a wide range of materials were used by the icons painters, mostly applied as mixtures of a proteinaceous material and a lipid one. The proteinaceous component proved to be mainly egg, though animal glue and casein were ascertained too, and proteins were often mixed; the lipid material was identified as linseed oil. In some of the icons pine resin and saccharide material were found. Data also highlighted that though the materials used in all the glass icons under study are similar, some particularities could be observed in the painting technique of the studied producing centers and icon painters.     

The Russian avant-garde painting palette: Documentary and physicochemical codification of organic colorants

In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.     

Recent advances in swollen-state NMR spectroscopy for the study of drying oils

The cross-linking processes of three drying oils (poppy, linseed, walnut), a class of organic compounds very important in the field of artworks, were studied by means of ¹H-NMR spectroscopy, following the change of the protons signals when oils are heated at 60 °C in the presence of air or nitrogen gas. This preliminary information is particularly important to identify the presence of drying oils within a solid painting film. We demonstrated that it was possible to study these films by swollen-state NMR, an innovative spectroscopy method that can directly analyze very small semisolid samples instead of solutions. The main advantages of this method are the short time of analysis, the possibility to analyze samples without any preliminary treatment, and the small quantity of the sample required. Therefore, swollen-state NMR technique was used to characterize three real painting films: in this way, we succeeded in recognizing in real paintings specimens the presence of drying oils employed as binders, avoiding any interferences due to other organic compounds acting as binding agents, like waxes or egg-yolk media.     

An integrated approach to the study of a reworked painting “Madonna with child” attributed to Pietro Lorenzetti

The painting “Madonna with Child”, attributed to Pietro Lorenzetti (14th century) and reworked around the middle of the 16th century, was studied by several techniques in order to characterize the materials used in the original and in the repainted areas. FORS, light microscopy, ESEM-EDX, ToF-SIMS and GC-MS were used. Red ochre and raw sienna earth were identified by FORS in the original parts of the painting. On the repainted parts of the panel, cinnabar, ultramarine blue and lead white were found. By means of GC-MS and ToF-SIMS measurements it was possible to identify the organic binding media used in the preparatory and painted layers.     

阿衡画牛半世纪

衢州孔氏家庙的藏画中,有一幅女画家阿衡创作的《百牛图》。这幅画有109头姿态各异的大牛小牛公牛母牛的水墨画,是用4张四尺宣纸拼起来的。阿衡的书法也很有特色,她另用30厘米宽的长条纸写了一篇《牛颂》,拼在画的天头上,更增添了《百牛图》的诗情与气势。     

Dating and technological features of wooden panel painting attributed to Cesare da Sesto

The most frequent dating methods of wooden artefacts are briefly introduced and discussed. Each of them shows merits and shortcomings. Therefore, an integrated approach of different techniques sometimes allows overcoming specific difficulties.The dating of a wooden support of a precious panel painting through a detailed xylological analysis and the joint use of dendrochronological and radiocarbon dating techniques is proposed. While any single dating technique demonstrated ineffective, the simultaneous use of several approaches in the study of the artefact led to excellent results in terms of both reliability and resolution, thus contributing to the inclusion of this painting in a specific historical period. On the basis of the performed dating, supported by the features of the panel and by a chemical-stratigraphic analysis of paint fragments, the artwork cannot be attributed to Cesare da Sesto.