A Monument of Byzantine Wall Painting—the Method of Construction

Abstract

Samples of pigments from excavated wall-paintings at the great civilization center of the Greek Bronze Age, Thera, have been analysed by the non-destructive methods of X-ray fluorescence, X-ray diffraction and mineralogical microscopic examination. The results showed that three types of blue pigment were used, namely the well-known Egyptian blue, glaucophane, which is a sodium magnesium (or iron) aluminium hydroxide silicate which occurs as a natural mineral on Santorini, and a mixture of Egyptian blue and glaucophane. Black pigments were rather puzzling in that some of them are carbon as expected, and some are manganese compounds. The rest of the pigments are very similar to those previously examined from Mycenae and Knossos.     

A cause of water-sensitivity in modern oil paint films: The formation of magnesium sulphate

Unvarnished twentieth-century oil paintings are often sensitive to aqueous swabbing, a method routinely employed by conservators for surface cleaning. This study proposes a connection between sensitivity and the presence of magnesium sulphate heptahydrate which has been identified on the surface of some of water-sensitive paintings. The probable source of magnesium is magnesium carbonate, an additive in some twentieth-century oil paints, which has reacted with atmospheric sulphur dioxide (SO₂). Films made using modern manufactured paints and formulations made in the laboratory were exposed to gaseous SO₂ and raised relative humidity and examined using scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction to characterize the crystalline entities. Films containing magnesium carbonate formed magnesium sulphite and sulphate hydrates. Films containing zinc oxide were also investigated. These formed zinc and sulphur containing salts. Sensitivity to swabbing with water before and after exposure was evaluated. Films that developed salts, demonstrated increased sensitivity to aqueous swabbing after exposure to SO₂. Findings suggest that increased water sensitivity may be due to a combination of the formation of hygroscopic degradation products and to weakening of the paint film due to salt-induced disruption of the surface.     

Trace Elements in White Lead and their Determination by Emission Spectrum and Neutron Activation Analysis

Abstract

A study was made of 21 renaissance plasters from Jacobean halls within a radius of 60km around Sheffield (England). The compositions of the plasters fell into two groups. Those prepared from carboniferous limestone contained calcium carbonate, quartz and animal hair but no free calcium hydroxide, despite claims in the literature that it might be found. The plasters which had been prepared from dolomitic limestone contained, in addition, magnesium carbonate and magnesium hydroxide.     

THE USE OF THE AIRBRASIVE PROCESS FOR CLEANING ETHNOLOGICAL MATERIALS

Abstract

Ethnological specimens of many different materials can be dry cleaned mechanically by means of a grit-spraying unit. Plain and painted leather, corroded metal, beadwork, metallic embroidery, wood, ivory, bone, basketry, some paper, pottery, shell, some textiles and stone are items which can be cleaned with less disturbance to the surface than is often occasioned by the use of other methods. A specimen constructed of several materials may be cleaned by this one method rather than by several, thereby also avoiding the use of water, solvents or other chemicals. The powdered abrasives used are calcium magnesium carbonate, sodium bicarbonate, glass beads, and several grades of aluminium oxide. Silicone carbide powder is used occasionally for very hard corrosion products on metal.     

The Conservation of Stained Glass

Abstract

The study of the structure and materials of ancient works of art has been much intensified with the development and use of improved analytical techniques. It was considered desirable to apply an X-ray fluorescence technique which could scan polished cross-sections of paint materials embedded in plastic. Layer thicknesses of 20–50 μ were successfully surveyed with an X-ray macroprobe attached to a fine-focus vacuum X-ray spectrograph. Elements above atomic number 16 in areas of 50 μ diameter were successfully detected and precisely located in the cross-section. The method has been applied particularly to the study of the technique of Rembrandt and Lievens paintings.     

Polishing treatments on ivory materials in the National Museum in Ravenna

Abstract

During the restoration of art works, data of great significance to art history frequently emerge. The purpose of our research is to throw light on the materials used in the past in the treatment and maintenance of works in ivory and bone. This has been achieved by conducting in-depth historical research into the specific literature and, thereafter, by examining with X-ray powder diffraction analysis and DTA and TG thermal analyses the accumulated deposits in the carvings and cavities of several artifacts belonging to the ivory collection housed in the National Museum in Ravenna.     

I. Azurite and Blue Verditer

Abstract

Samples of pigments from excavated wall paintings of Vergina’s second tomb were analyzed by the non-destructive methods of X-ray fluorescence, X-ray diffraction and mineralogical microscopic examinations. The results showed that one type of blue pigment was used, the well-known Egyptian blue. The red pigments, except one which is haematite, are cinnabar (HgS), and the grey pigments are carbon. None of the black pigments contained manganese compounds.     

Preliminary study on the impact of relative humidity on the conservation of jades

Abstract

This paper examines the impact of relative humidity on jades by enclosing the samples under constant relative humidity (RH) of 32, 49, 61.5, and 81.7% at the same temperature of 40 ± 0.1°C for 160 days. The simulated samples were pure and dense tremolite jade and serpentine jade, impure tremolite jade and serpentine jade containing some calcite, and serpentinized calcite, which are all common materials of ancient jade found in archaeological excavations. All samples were characterized through particle-induced X-ray emission and a glossmeter. The degree of deterioration proved to be greater in impure materials than in pure ones. The best RH to conserve various kinds of materials differs: for pure tremolite and serpentine, all of the RH levels are equal; for impure tremolite with some calcite, 61.5 and 81.7% were superior; for impure serpentine with some calcite, the highest RH (81.7%) was best; and as to the serpentinized calcite, there is no clear conclusion as yet and further research is needed.     

Material characterization,stratigraphy, textures,and painting techniques of the mural painting The Allegory of the Industrial Development of São Paulo by Fulvio Pennacchi

ABSTRACT

This work presents a study of samples of the mural painting The Allegory of the Industrial Development of São Paulo (Alegoria ao Desenvolvimento Industrial Paulista), made in the city of São Paulo, Brazil, by the artist Fulvio Pennacchi. Using transmitted light petrographic microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry, and X-ray fluorescence, the stratigraphy, the textures, the mineralogy, and the chemical compositions of the mural were established; therefore the painting techniques, pigments, and materials applied by the artist were identified. The mural was painted with the fresco technique and variations. This technique involves the use of materials of mineral origin, both in the support and for the pigments. About the artist’s relevance, Fulvio Pennacchi is considered an important muralist of his time, being one of the pioneers in the production of frescoes in Brazil. The mural, measuring approximately 11?×?6?m, painted in 1954, was removed from where it was originally made, in consequence of a fire that affected the place. Specialized engineers transported it, and today it is stored awaiting restoration. The data presented here can support the process of restoration of the mural, as well as contribute to the improvement of protocols for the analysis of works of art, and to the historical record of mural painting techniques over time.     

A Characterization Method for the Fifth-Century Traditional Mortars in the Land Walls of Constantinople,Yedikule

Abstract

A characterization method was designed to improve understanding of ancient mortars used in the land walls of Istanbul, Turkey. The mortars had hydraulic properties where slaked lime was the binder and crushed brick was the aggregate. For characterization purposes simple chemical and petrographic analyses may be sufficient. However, further scientific research based on instrumental analysis is needed for an understanding of ancient lime technologies, provenance of the materials and deterioration processes. Besides simple chemical and petrographic analysis, this paper describes the differential thermal analysis (DTA), inductively coupled plasma analysis (ICP), X-ray diffraction analysis (XRD), scanning electron microscope–energy dispersive X-ray analysis (SEM-EDX) and mercury intrusion tests that were conducted to evaluate the binders and aggregates of the samples. Their physical and mechanical properties were also determined, and salt decay is discussed. It was seen that limestone chips and river sand were used as aggregates, in addition to crushed brick. The brick dust served as an artificial pozzolanic additive. Salt decay originated from sea spray and air pollution.     

A note on the analysis of metal threads

Abstract

The present work demonstrates by means of two practical examples the extreme importance of examination of cross sections of metal threads to obtain an overview of their structure and of the different materials employed in their manufacture. Problems that might be caused by disturbance of surface features during polishing were prevented by covering the sample before embedding with a layer of nickel, using electroless deposition. Results from scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) showed that, although the mean chemical composition of both metal wires is the same, their metallurgical structure is completely different: one consisting of pure silver with inclusions of copper particles and the other a silver–copper alloy.     

Investigation of the materials found in the studio of Francis Bacon (1909–1992)

Abstract

The investigation of materials found in Bacon's studio is reported. The contents of the studio are examined and interpreted to identify the materials and colours most favoured by Bacon, and the range of media used. A small number of colours appear to have been heavily used. Some objects used as tools in the painting process are also investigated and explain textures seen in paint in his works. Samples of selected materials from the studio are analysed to identify the components of paints (pigments, extenders, and binders) used by Bacon. This investigation is part of a wider project examining his materials and techniques. The analytical information obtained here from the studio helps to clarify the statements made by Bacon in interviews regarding his use of materials and is proving useful in the identification of materials in his paintings, in order to help with the conservation and authentication of his works.     

Sanguine Paint: Production,Characterization, and Adhesion to the Glass Substrate

ABSTRACT

For centuries, the only painting materials used in stained-glass production were grisaille and yellow (silver) stain. At the end of the fifteenth century, stained-glass painters began to use a new material, sanguine. This paint is mainly produced with iron oxide particles, usually haematite, and allowed to obtain a colour that can vary from yellowish to brownish-red due to the nature and particle size of the iron oxide. A translucent sanguine was mostly applied as flesh and hair colour, with an opaque sanguine used for drapery, architectural motifs, and heraldry. The main goal of this study is to investigate the relationship between historic sources on the preparation and use of sanguine from the fifteenth to the nineteenth centuries and the evolution evidenced in the recipes regarding the production method. Representative recipes from several centuries (sixteenth to nineteenth centuries) were selected and reproduced for this study. These reconstructions were thoroughly characterized using X-ray powder diffraction, optical microscopy (OM), and fibre optic reflectance spectroscopy (FORS). The OM and FORS data were correlated with historic sanguine paints applied on historic stained-glass. The similarities and differences between historic and reconstructed paints are presented. The study of reconstructed sanguine’s adhesion to glass using cross-cut testing was also performed, revealing that the adhesion is strongly influenced, not only by the binder, but also by the composition and morphology of the sanguine paint.     

Pattern-welding and Damascening of Sword-blades—Part I Pattern-Welding

Abstract

Marble specimens were impregnated with epoxy resins by first soaking the specimens in a solvent and then treating them, in steps, with increasing concentrations of the resin in the resin-solvent mixture. This resulted in impregnation to several centimeters’ depth into the specimen. Both impregnated and non-impregnated specimens were subjected to 3000 ppm SO₂ atmospheres in a dynamic system. X-ray diffraction and fluorescence studies to determine the deterioration quantitatively, revealed that transformation of the outer layer of non-impregnated marble into primarily calcium sulfite stopped after a maximum of 15 mole percent conversion under normal conditions of humidity. While certain impregnated marble specimens showed significant protection from SO₂ attack, other impregnated specimens revealed more reactivity than the controls. A partial explanation of this has been obtained by scanning electron microscopy which showed that the resin films on the surface were perforated. Coatings of certain acrylics provided some additional protection to impregnated specimens.     

The materials and techniques used in the paintings of Francis Bacon (1909–1992)

Abstract

Materials from 38 paintings by Francis Bacon (1909–1992), including 21 complete works and 17 partially destroyed canvases are investigated. Observations are made of the artist's technique and details are compiled of the supports used. Samples of paint and priming were taken for analysis using polarized light microscopy, Fourier transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), pyrolysis–GC–MS (Py–GC–MS), and scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM–EDX). Analysis of priming layers appears to show that the priming composition correlates well with particular ranges of dates. A fairly limited range of materials are found, with many of the same pigments found in works spanning Bacon's career, though other pigments were introduced at different stages in his career. Oil paints were used consistently for the painting of figures, but household paints were increasingly used in backgrounds from the 1960s onwards. A variety of different synthetic media are found in later works, including household acrylic paints and spray paints. Increased knowledge of Bacon’s materials is expected to be of great value to conservators caring for the work of this highly significant artist, and is already helping in the authentication of works attributed to him.     

TOXICITY OF BENZOTRIAZOLE

Abstract

Blue and white Chinese porcelain specimens from Dehua and Zhangzhou kiln sites from the Ming dynasty (AD 1368–1644), and Jingdezhen kiln sites from the Yuan (AD 1280–1368) to Ming dynasties were collected. The chemical compositions of these valuable samples were determined using energy dispersive X-ray, fluorescence (EDXRF) spectrometry, a non-destructive method, and some Jingdezhen samples were analyzed by scanning electron microscopy and transmission electron microscopy. The EDXRF results were subjected to correspondence analysis. Differences in the composition of the specimen bodies were found for specimens from different production sites. The blue and white Jingdezhen imperial, porcelain from the Yuan to Ming dynasties can be divided into two periods based on differences in the chemical composztion and microstructure of the pigments. The reasons for these variations are discussed.     

Materials and techniques in the pictorial oeuvre of Lucio Fontana

Abstract

The painting materials used by Lucio Fontana were investigated through the analysis of 28 Spatial Concept works created between the early 1950s and the artist's death in 1968. The pictorial media were analyzed by means of numerous techniques including Fourier transform infrared spectroscopy, pyrolysis-gas chromatography–mass spectrometry, scanning electron microscopy, and X-ray fluorescence. This study has provided a more complete understanding of the artist's technique, as it was found that Lucio Fontana had already begun experimenting with new synthetic pictorial and binding media such as alkyds and polyvinyl acetates at the beginning of the 1950s, and polyesters during the early 1960s. Although he never abandoned the use of commercial oil paints, Fontana's application of these new materials continued in an infinitely varied search for innovative expressive effects. The characterization results explain the physical and mechanical properties of the paint layers, and may be correlated with the conservation state of the works analyzed. All the results have been compiled and are discussed together with the artist's practices and their evolution over time.     

Prediction of the relative humidity response of backboard-protected canvas paintings

Abstract

simple mathematical model is presented that predicts the decay time of the internal relative humidity (RH) of backboard-protected canvas paintings when subjected to external RH fluctuations. The model takes into account the permeance of the canvas and the hygroscopicity of the enclosed materials. Predictions from the model are tested experimentally. The wooden stretcher releases moisture more slowly than expected, providing less buffering than predicted by the model. The practical implications of these findings are discussed.     

Restoration of a 15th-Century Romanian Court Garment

Abstract

Samples of pigments from a wall-painting of a house of the first Pompeian style (400 Bc–168 BC) found in Pella, Greece, were analyzed by the non-destructive methods of X-ray fluorescence and X-ray diffraction. Red pigments were identified as cinnabar and iron oxide pigments (haematite and goethite). Blue was the well-known Egyptian blue and yellow was identified as goethite. A characteristic feature of the wall-painting was the presenceof green earth, i.e. celadonite and glauconite, encountered for the first time in this series of investigations.