SOME ASPECTS OF THE CONSERVATION OF WORKS OF ART IN BUILDINGS OF NEW CONCRETE

Abstract

This paper deals with the materials used in conservation treatments in the first half of the twentieth century for the preservation and consolidation of wooden art objects from the Saxony region in Germany. The use of such materials must be seen as early attempts to find a conservation treatment for wood. The documentation of conservation treatments provides a reference to the application of oils and oil–resin mixtures. The results from the chemical analysis of samples of historic preservatives from the beginning to the middle of the twentieth century (so-called 'Puckelin') carried out by gas chromatography–mass spectrometry (GC-MS) and Fourier transform infrared (FTIR) analysis confirm the use of tung oil as a drying oil, whereas the use of linseed oil cannot be excluded. Colophony and, probably, amber varnish were used as resinous constituents. There are indications that a conservation material dating from the second half of the twentieth century most likely contained rapeseed oil.     

Scanning electron microscope hypsometry as a tool for evaluating the impact of surface treatments: A case study on sub-fossil bone

Abstract

Plaster of Paris field jackets are commonly employed for lifting fragile archeological and paleontological material during excavation. When the plaster has been applied directly to the object surface its removal poses a severe risk of damage and loss. This study documents the development of an experimental method to test the suitability of various techniques for removing plaster of Paris from sub-fossil bone. The use of digital microscopic elevation models, already in use in other disciplines, was tested as a method for quantifying surface loss resulting from conservation treatments. The study concludes that citric acid is not suitable for use in close proximity to sub-fossil bone. Air abrasion and laser ablation proved extremely damaging, but ultrasonic cleaning caused no detectable damage. This study has relevance to the removal of plaster of Paris from other materials, such as carbonaceous statuary. The analytical technique itself has a far wider application and is recommended for evaluation of all surface treatments that have the potential to cause loss on a microscopic scale.     

Thermal Stress as a Possible Cause of Paintwork Loss in Medieval Stained Glass Windows

Abstract

One of the main causes of the loss of paintwork from medieval stained glass windows is the propagation of cracks in the grisaille and in the underlying glass, which cannot be considered the result of a stabilization process, but the evidence of an ongoing stress. The thermal behaviour of different-coloured painted glass pieces exposed to direct solar radiation was investigated in order to study the effect of thermal stresses on the conservation of the paintwork. Experimental results have been compared with laboratory tests as well as with measurements carried out on original stained glass windows. The grisaille showed a thermal behaviour similar to that of the glass on which it is fired. A clear correlation was found between the glass thermal cycles, the increase in stress at the glass–grisaille interface and the growth of cracks in the grisaille. According to these results, protective glazing aids the preservation of the paintwork from the risk of damage and loss, reducing the thermal stresses on the glass of the stained glass windows in terms of amplitude and frequency.     

A SIMPLE METHOD FOR THE IDENTIFICATION OF INDIGO

Abstract

Before commencing the conservation treatment of a fifteenth-century coffered ceiling in the convent of Santa Fe, Toledo, the painting materials were analyzed. Elemental analysis of the pigments was carried out by XRF spectrometry. Cross-sections were made of the samples for optical microscopy. The binding media and the varnish were identified by gas chromatography, by analyzing the fatty acids, terpenes and amino acids. Once the painting had been studied, consolidation treatment was applied using different materials according to the solubility of the paint layers. Animal glue was mainly used, and Paraloid B-72 to a lesser extent, as a preliminary to the structural reinforcement of the support.     

Blue Enamel on Sixteenth - and Seventeenth-Century Window Glass

Abstract

It is still unclear why some of the blue enamel on sixteenth- and seventeenth-century stained window glass is flaking off, while enamel layers with other colours are still in relatively good condition. In order to obtain a better understanding of this conservation problem, 31 historical recipes used for the fabrication of blue enamel were compared with results from the chemical analysis of 25 historic samples. The chemical composition and the microstructure of the enamels were analysed in cross-section by means of electron probe microanalysis (EPMA). This study demonstrated that the variation in chemical composition of the samples can be explained by the use of the wide range of recipes existing at that time. Although this study gave an insight into the composition, heterogeneity and use of colouring substances, no clear relation could be found between the parameters analysed and the deterioration rate of the blue enamel paint layer.     

Confocal XRF depth profiling non-destructively reveals the original blue pigments in a Renaissance painting by Caroto

Recent restoration of The Rest on the Flight into Egypt by Giovanni Francesco Caroto, from the Louvre collections, included a technical examination of the Virgin's blue robe that aimed to characterize the original materials and later additions. The painting was examined using light microscopy and ultraviolet and infrared imaging, and one cross section was taken. None of these methods showed a clear distinction between the layers that were artist applied or modifications made by another hand. To gain information about the paint stratigraphy without taking additional samples, non-invasive confocal X-ray fluorescence (CXRF) analysis was carried out to examine several areas of the Virgin's robe. Using this technique, it was possible to identify the pigments and order of application of paint by the artist. All the pigments identified were considered to be artist applied, and on this basis no further cleaning was carried out and conservation proceeded with retouching of minor areas of loss or damage. This study highlights the advantages of CXRF analysis for the technical study of paintings, used in combination with classical methods for making informed conservation treatment decisions.     

The treatment of ancient Portuguese tiles

Abstract

The preservation of the vast cultural heritage of tiles in Portugal requires the development of a systematic scientific and technological approach. In this communication the case of the treatment of a panel of ancient tIles is described. The main problem was the cleaning and consolidation of the piece, followed by restoration for exhibition. The treatment was preceded by a study of the materials, consisting of analyses of the ceramic body and the glazed surface. The removal of aged waxes and resins was achieved using appropriate solvents and the consolidation of the ceramic body was carried out by an inorganic treatment. For the reconstruction of missing parts and the mounting of the panel materials were chosen which would avoid interaction with the original material.     

Changing research trends in the field of archaeological wood at the Conservation Department,Faculty of Archaeology,Cairo University

Abstract

Since 1980, much research in the field of treatment and conservation of archaeological wood has been carried out at the Conservation Department, Faculty of Archaeology, Cairo University. Materials and methods used in conservation have been changing gradually over the years worldwide. It was necessary to study critically previous masters and doctoral dissertations on Egyptian archaeological and historic wood, all written in Arabic. This review of them includes a brief history of the Conservation Department at Cairo University and five main focal points of past research: types of wood used throughout Egyptian history, assessment of wood decay, wood properties and composition, treatment and conservation of decorated wood, and the evaluation of chemicals and polymers used in the treatment of archaeological wood and composite objects containing wood.     

Conservation Heating 24 Years On

ABSTRACT

Control of relative humidity (RH) for collections care is challenging in U.K. historic houses because they are often highly ventilated with poor heat retention, a porous building fabric and naturally tend to high (60–80%) RH if unheated. The significance of the building means that large-scale modifications and installation of air handling systems may be unfeasible and undesirable for the conservation of the building. In the late 1980s the National Trust, for English, Wales and Northern Ireland, investigated conservation heating as an RH control method that works with the natural environment of historic buildings, mimicking historic heating and requiring only modification of existing heating services or a light touch installation of new heating systems. The National Trust adopted conservation heating as its preferred method for environmental control in historic buildings from the 1990s. This method was presented at the IIC 1994 Ottawa congress on preventive conservation. Conservation heating has since been adopted by many historic house management organisations, particularly across north-west Europe, where it is well suited to the climate. This paper reviews conservation heating developments implemented by the National Trust since 1994, in response to a changing external context, new knowledge and developments in operational practice.     

The Cathedrals of England: Environmental Performance,Conservation and Exhibitions

ABSTRACT

English medieval cathedrals are a group of buildings of exceptional significance and they contain collections of equal importance. Both the historic building fabric and the artefacts are vulnerable to environmental deterioration. However, unlike buildings owned by heritage organisations, the primary purpose of cathedrals is to further the Christian mission, and the conservation of the building and collections is required to be conducted within these constraints. Increasing visitor numbers and the installation of sophisticated exhibitions makes the task of conservation all the more demanding. Next to mechanical damage, environmental factors are the greatest source of deterioration to sensitive fabric and collections. However, until recently, there has been little systematic study of English cathedral environments and the effects of different uses and control measures. Detailed studies undertaken on 20 cathedrals in the past two decades have provided an insight into their environmental performance and how they differ as a group from many other historic buildings, as well as the passive conservation measures that can be implemented within their primary function.     

Disfiguring organic residues on industrially produced sheet metal coupons simulating copper and brass works of art by Donald Judd: Attenuated total reflectance Fourier transform infrared spectroscopy analysis and treatment recommendations

Abstract

The Minimalist work of Donald Judd exemplifies modern and contemporary works of art that utilize the appearance of bare metal as an integral component of the artist's intent. Decades after fabrication, disfiguring patterns have appeared on the surfaces of many such works. These patterns are not related to the formation of tarnish or other corrosion effects caused by improper storage, display, or transportation and handling; rather, they are associated with the initial processing of the metal sheets and subsequent fabrication of the art objects. Due to the challenges of obtaining analytical data directly from works of art, the authors present results from industrial sheet metal coupons prepared to simulate materials and techniques used in Donald Judd's copper and brass artworks. Attenuated total reflectance Fourier transform infrared spectroscopy carried out on each side of 55 coupons indicated the presence of organic materials such as long-chain aliphatic hydrocarbons, esters, and ethers, consistent with the types of compounds used in industrial lubricants. In addition to conducting the first systematic instrumental analysis of these residues, the authors propose the use of specific solvents for their removal as an alternative to abrasive methods, which cause removal of original surface from the objects.     

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.     

A Preliminary Evaluation of the Surfaces of Acrylic Emulsion Paint Films and the Effects of Wet-Cleaning Treatment by Atomic Force Microscopy (AFM)

Abstract

The surfaces of acrylic emulsion (dispersion) paint films were investigated by atomic force microscopy (AFM), with supporting chemical information provided via infrared spectroscopy. The morphological and chemical features of the surfaces of a series of recently cast reference paint films were explored, including characterization of changes induced by exposure to water and mineral spirits. A portable in situ AFM system was also used to document the surfaces of acrylic emulsion paintings in Tate's collection. The complete and partial removal of migrated surfactant was successfully imaged alongside features arising from mechanical action. Differences in paint surfaces and migrated surfactant layers were observed in relation to pigment type, paint brand and exposure to accelerated ageing, in addition to applied wet surface cleaning treatments. The findings contribute to further understanding of the subtle changes occurring at acrylic emulsion paint film surfaces and are relevant to current debates on the removal/disturbance of original surface surfactant from these films through conservation treatment.     

A selected review of the literature on library co-operation

Abstract

A study of broadcasting libraries in Nigeria was carried out using the social survey method. Questionnaire, observation, and interview techniques were used to generate data from a representative sample of the nation's broadcast media stations (radio and television) located in the Bauchi and Plateau States of Nigeria. A general underdevelopment of the libraries was revealed. Staffing is inadequate in number and is also non-specialized. Preservation and conservation practices are virtually non-existent. Whereas the content of the modest collection shows a rich resource base, collection development is near-crippled while mediagraphic control is done more by common-sense than by any system. State stations generally fared better than federal ones. Poor funding was identified as the major constraint in the general development of the libraries. Suggestions were offered towards revenue generation and the need for professional leadership in the country's broadcasting libraries.     

Overcoming Obstacles to Preventive Conservation Projects in Italy: With a Case Study of the Savoy Carriage Collection of the Presidency of the Republic

ABSTRACT

Working on preventive conservation in Italy is difficult but not impossible. After small successes and setbacks convincing museums to adopt elements of preventive conservation in the 1990s, the first author (Rossi Doria) was contracted for 15 years to preserve the historic carriages and associated objects of the Presidency of the Republic of Italy. This required patience to overcome or circumvent obstacles such as an inflexible bureaucracy and the absence of any formal recognition of preventive conservation within the educational and contractual systems for heritage conservation. The key factors in his success were the support of the curators, the financial and planning autonomy of the Presidency, and the obvious need for conservation and preservation of these elegant and complex objects. The program began in 2001 with the recovery of the forgotten collection from inappropriate storage in several locations. The entire collection was surveyed and recorded, not only the carriages but also thousands of harnesses, saddles, clothing, fabrics, weapons and memorabilia. Multiple preventive and interventive actions were undertaken, such as pest eradication for all sensitive materials, environmental surveys, and everyday maintenance, as well as complex treatments for the ornate carriages. Analysis by country of published articles on preventive conservation and of IIC membership both confirm that the topic is not as well established in Italy as in many other countries. Some reasons and solutions are proposed.     

Study of Post-World War II French Aeronautical Aluminium Alloy and Coatings: Historical and Materials Science Approach

ABSTRACT

In many countries, collections of historic aircraft, conserved in Air and Space museums or local associations, reflect the importance of a national or local history. Mostly parked outdoors, aircraft suffer from significant corrosion requiring conservation operations. During renovation, metallic parts are often replaced by association members. This can lead to a major loss of information since industrial archives dealing with materials and processes do not always survive. However, if these elements can be considered, they could be a fundamental source of information on the materials originally used and of the technical history of aeronautics. This work reports a thorough study of aluminium-based alloy parts collected on a Breguet aeroplane dating from the 1950s, during its recent renovation. Thanks to an approach coupling multi-scale material characterisation and research in archives, information on the industrial knowledge is revealed. Several historic grades of aluminium-based alloys were found, namely A-U4G, A-U4G1, and A-U3G, depending on the role of the part. Similarly, different protective coatings were identified (anodic oxidation, primers, and paintings), depending on the role of the metallic part and its location in the plane. Knowledge of the materials from bulk metal to the coated surface is necessary for good conservation practices regarding aeronautical heritage artefacts. Related documents and archives also fundamentally help in understanding such complex artefacts.     

NOTE ON THE TECHNIQUE AND CONSERVATION OF SOME THANG-KA PAINTINGS

Abstract

The article is a concise report on the art historical as well as technical aspects of thang-ka paintings. It also describes briefly the traditional methods and materials employed in the execution of these paintings. The artists’ materials described in the literature are compared with actual findings as a result of analysis of pigments, binding media and other materials involved in the execution of the thang-ka paintings. An outline of the causes of deterioration of thang-kas is also mentioned. Finally, an extensive account is given of the method of treatment carried out in the author's laboratory.     

Study and Conservation of the St. Nicola's Basilica Mosaics (Bari,Italy) by Photogrammetric Survey: Mapping of Polychrome Marbles,Decorative Patterns and Past Restorations

ABSTRACT

This present work focuses on the mapping of marbles, decorative patterns and area of the mosaics of the St. Nicola’s Basilica in Bari (Italy) by their photogrammetric survey. The extraordinary importance of these mosaics is due to the stylistic uniqueness and the undisputed workmanship and to the employed materials for tesserae. These mosaics include the white and polychrome marbles, used in the Roman age and reused in medieval artistic production, and imitation stones used as substitutes during the past restorations. The digital survey was realised by the photogrammetric reconstruction of mosaics collecting a photo dataset, after the mosaics redrawing by an image processing software and finally implemented it with lithological identification marbles. It allowed to obtain a punctual mapping of materials, through which to identify original areas and restoration areas, decorative patterns, recurring geometries. The research carried out, supported by the photogrammetric reconstruction as established method for high resolution digital reproduction and mapping, not only ensures the conservation and improvement of the enjoyment of the mosaic floors of the St. Nicola’s Basilica, but allows to conduct studies on materials, decorative patterns and restoration areas directly on the digitized product.     

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.