Accessing the Old and the New

Summary

The University of Arizona Library's tradition of outreach to the surrounding community is reflected in two examples of projects detailed here. The first project is a series of Web exhibits created by librarians and individuals from the community that explore the history of Tucson and southern Arizona. Some of the Web exhibits detail the experiences of immigrant and Native American cultures in the area while other Web exhibits deal more generally with the history of the area. The second project involves a Federal grant that will make certain parts of library's Special Collections more accessible to the community by building new facilities that are open longer hours, digitizing some of the materials and adding computer workstations for users.     

Assessment of Different Methods for Cleaning the Limestone Façades of the Former Workers Hospital of Madrid,Spain

Abstract

Five different methods for cleaning the limestone façades on what was originally the Workers Hospital in Madrid are analyzed in this paper. Due to the pollution in the surrounding air, just 20 years after a prior cleaning operation, sulfate crusts had developed on the entire stone surface of the building. The gypsum mortar used in the original masonry constituted an additional source of sulfur. Limestone is a traditional building material in Madrid and its surroundings. The petrography, mineralogy and petrophysical properties of the biomicrite, pelmicrite and biopelmicrite varieties of limestone identified in the hospital walls were determined. Analysis of a black layer on the stone surface showed that it consisted primarily of sulfate crusts. The cleaning methods tested were alkaline gels (sodium hydroxide and potassium hydroxide), pressurized hot water, glass bead blasting and latex peeling. The criteria for assessing the effectiveness and potential risks of the various cleaning systems included changes in the chromatic parameters of the stone, the formation of alteration products (i.e. salts) and modification of the stone surface. The stones cleaned with the three most effective methods, together with a rain-washed stone as a reference, were washed with water to generate an artificial runoff. The collected drain water was analyzed to determine the presence of any by-products from the cleaning process. The method found to be most effective and which caused the least alteration to the stone surface was glass bead blasting, particularly after adjustment of the bead size and pressure conditions used for the test.     

THE CONSERVATION OF A PRESERVED HUMAN HEAD

Abstract

Large ethnographical collections sometimes contain examples of preserved human heads. There are those from the Maori of New Zealand, the well-known Jivaro Indian shrunken heads, and others from Papua-New Guinea. The article describes the preservation process as practised in Western Papua by the tribal craftsman, and then the problems of conservation in the museum laboratory. The latter include the cleaning of the skin, and the painted areas of the face, with the non-ionic surface-active agent Lissapol N in distilled water, followed by consolidation of the painted surface with an application of 2 % soluble nylon in industrial methylated spirit. Clay and fibre within the head were consolidated with a 5 % solution of the polymethacrylic ester Bedacryl 122X (I.C.I.) in xylene; and the fibre ear ornaments, after cleaning with Lissapol N, were consolidated with a 5 % solution of soluble nylon in industrial methylated spirit. The specimen was fitted with a specially made polythene cover, and stored in an individual box.     

THE CONSERVATION OF NON-METALLIC SEALS

Abstract

The conservation of non-metallic seals is an aspect of archival conservation which is all too often neglected.The authors show the most usual causes and forms of damage together with various methods of treatment. Among the aspects discussed are composition and manufacture; cleaning and repair of single and double-faced seals made of beeswax, shellac and other thermoplastic compounds; the conservation and repair of papered seals, together with seals and wafers applied en placard to documents; and methods of packing and storage used in the University of Glasgow Archives.     

Evaluation of Conservation Treatments Applied to Salted Paper Prints,Cyanotypes and Platinotypes

Abstract

As the great majority of photographic prints have a paper support, their conservation has been based on conservation treatments traditionally used by paper conservators. It cannot be assumed, however, that these standard treatments, that are employed on paper without any problem, will give comparable results on photographic prints. The effects of mechanical cleaning, solvent cleaning, wet cleaning, bleaching and deacidification on salted papers, cyanotypes and platinotypes are investigated and discussed. The treatments were separated into those that gave clearly negative results and should be rejected, and those that should be studied in depth before accepting them as suitable. It was shown that the use of some types of bleaching and deacidification agents can be very dangerous in the case of plain paper prints. Cyanotypes proved to be the most sensitive to any treatment method and platinotypes the most resistant.     

Academic Engagement in the Library Commons

Abstract

Beginning in July 2002, the Health Sciences Library at the University of North Carolina at Chapel Hill underwent an 11 million dollar renovation. During three phases of the renovation, parts of the collection were inaccessible to patrons. In order to continue to make the library's collection available, library staff created a paging system. Patrons submitted requests for needed library materials using paper and electronic forms and library staff retrieved the requested items. The paging service was modified three times based on prior experience. Patrons were generally satisfied with the service. The renovation ended in December 2004.     

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.     

THE CONSERVATION OF TAPESTRIES FOR MUSEUM DISPLAY

Abstract

A broad outline of the considerations which arise with regard to the conservation of a museum collection of tapestries is given in this paper. The various types of damage to, and deterioration of, tapestries is discussed.

Various methods of washing and dry cleaning, and the equipment necessary for these procedures, are reviewed, and a caution is included as to the necessity of testing all dyes for colour fastness in both water and any solvent used for dry cleaning. The equipment, materials and techniques of repair are discussed; three methods of repair being currently used in museums and specialist workshops — re-weaving, stitching on to a backing and the use of synthetic resins for impregnation and adhesion to a woven support. It is suggested in conclusion that the optimum method of repair in museums is stitching on to a backing. More research must be undertaken into the use of synthetic resins, and re-weaving usually alters the original appearance of the tapestry.

Finally, the need for specialised conservation staff in a museum with a tapestry collection is emphasised.     

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.     

Some conservation problems encountered with turmeric on ethnographic objects

Abstract

The pH dependency of turmeric, used as a dye or pigment on ethnographic objects from the Santa Cruz Islands, can present a conservation problem. Great care must be taken with the cleaning, consolidation, repair, storage and display of objects of this nature. A section on the analysis of suspected turmeric is included.     

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.     

Mineralogical-chemical Alteration and Origin of Ignimbritic Stones Used in the Old Cathedral of Nostra Signora di Castro (Sardinia,Italy)

ABSTRACT

The pyroclastic rocks belonging to the Late Eocene-Miocene volcanic activity that occurred in Sardinia between 38 and 15 Ma ago were widely used as construction materials in several Romanesque churches of the easternmost Logudoro area, as well as in large parts of the Sardinia territory. In this work, the ancient Cathedral of Nostra Signora di Castro (twelfth century) was taken as a representative case study. There is no historical or archaeological evidence of ancient quarries. Based on the geochemical, petrographic, and volcanological data on several samples from an extensive field area (approximately 150?km²), a geographical zoning of the volcanics has been recognised. In the Oschiri sector, there are three different sub-zones, which can be identified with different volcanic rocks: less fractionated rocks (Differentation Index ～70–78); intermediately fractionated rocks (D.I. ～76–79); and more fractionated rocks (D.I. ～77–82). To identify the origin of the ignimbrite rocks of the Church of Nostra Signora di Castro, two statistical methods were used: stepwise linear discriminant and canonical analysis. Moreover, to define the geochemical transformation processes induced by the alteration, a comparative study of concentrations of major and trace elements measured by XRF and SEM-EDX analyses on the surface portion and the innermost areas of the stone was made.     

The nature of a whewellite-rich rock crust associated with pictographs in southwestern Texas

Abstract

A whewellite-rich rock crust covers vast areas of limestone inside dry rock shelters and under rock overhangs throughout the Lower Pecos Region in southwestern Texas (USA). The natural rock crust, composed primarily of whewellite and gypsum with lesser amounts of quartz and silicates, encapsulates the paints of the extraordinary pictographs at more than 250 rock art sites in the region. The authors propose a model that describes the origin of each crust constituent and the evolution of these surfaces. Furthermore, they describe the relationship between the ancient paints and crust matrices, information that is necessary for the development of sound conservation strategies.     

An Experiment In Co-operative Conservation

Abstract

A very heavily corroded Egyptian bronze statuette of Amon was cleaned by handpicking and found to be composed of six separately cast parts: two elements of head, two arms, the torso with legs, and the beard. Such cases do not seem to be unusual but are rarely observed because of beautifully concealed joins. Technical details of the mechanical methods of cleaning are given and some critical comments included on chemical and electrolytic methods: it has to be remembered that cleaning is an irreversible process. Attention is also given to analytical problems in heterogeneous objects such as this.     

Economics of Dust

Abstract

Dust presents a physical risk to objects and reduces evidential value; it also creates a perception of poor standards of care. However, cleaning also imposes risks of damage, takes time and costs money. The presence of visitors induces much of the dust found in properties, so increasing or extending access has implications for housekeeping that are rarely discussed in economic terms, despite the fact that dust control represents the most expensive element of preventive conservation in historic houses. The range of preventive and protective measures that minimize the deposition of dust also carry costs that often relate to visitor flow. Simple economic calculations show the balance between the costs of cleaning and of other equipment and materials in National Trust properties. The cost per visitor initially reduces with increased numbers of people, but at high flow rates expenditure can increase because of the cost of cleaning. The per capita conservation costs become less than UK?2 per visitor at reasonable visitor flow rates (about 30000 per annum), although, in the calculations presented here for an idealized medium-sized property, costs begin to increase as visitor flow rises above 60000 per annum. Recognizing the economic importance of managing dust is thus essential in assessing the level of access consistent with maintaining appropriate standards of presentation and collections care.     

Migrating facsimiles: When copies disappear from conservation control

A 2014 exhibition of Meriç Algün Ringborg at Moderna Museet, Stockholm, Sweden, exploring identity and belonging involved the making of facsimiles. The installation included a sound work, booklets to be taken, and a book to be read. Exhibition copies were created of personal letters for open display which were not to be touched. Contrary to the artist's wishes, the work was constantly handled. Made for this one installation, the facsimiles transcended the exhibition and were returned with the work to the artist. The paper examines issues of authenticity and control from a conservation standpoint, and details discussions surrounding reproduction in contemporary art museum conservation practice.     

Calcium Carbonate on Bronze Finds

Abstract

The removal of calcareous accretions from archaeological bronzes can be a difficult step in their conservation. Chemical cleaning with chelating agents might be an alternative to mechanical methods. In this study the use of the chelating agent sodium tripolyphosphate (STPP) was examined to determine whether it is effective in discriminating between calcium carbonate and copper patina, and non-corrosive to copper alloys in the presence of air. Comparative experiments with STPP and disodium ethylenediamine-tetraacetate (Na₂-EDTA) were carried out on synthetic malachite, cuprite, calcium carbonate, naturally polished malachite surfaces and sheets of bronze and brass. In addition to the properties of the chelating agent, the solubility of the salts and the pH values of the solutions are crucial factors in the removal of compounds of low solubility. The quantity of metal ions dissolved, estimated by atomic absorption spectral analysis and scanning electron microscopy, showed that the calcareous accretions could be removed satisfactorily, but STPP also dissolved constituent parts of the patina, such as malachite and cuprite, and may harm bronze or brass. Compared to Na₂-EDTA, STPP is less effective in dissolving calcium carbonate. It is less harmful to the patina and base metal, but may lead to patination of the underlying metal.     

Detection and Virtual Reconstruction of the Original Form of a Rock Relief,Lost in Part by Water Erosion

ABSTRACT

Historic rock reliefs are magnificent monuments that represent special events of the past. Due to exposure to the natural environment, these monuments are affected by natural and human erosion mechanisms. Many of them have disappeared over time and are no longer recognizable. This research seeks to find a way to understand the initial shapes of the rock reliefs that have been exposed to steady and prolonged erosion. For this purpose, a case study was selected in southern Iran that has been damaged over hundreds of years by a stream of water and has partially disappeared. The water flow has caused a groove to be formed along the cliff and apparently a strip of the relief has disappeared. Documenting the inner surface of the groove revealed that this surface is not smooth and there are still remnants of unclear reliefs in eroded sections. By examining the erosion effects on initially vertical smooth sections, it was possible to arrive at a formula to determine the damage caused by the water flow on cliffs. Based on this, it was determined to what extent the water flow had reduced the amount of rock at each height. Accordingly, each level of the damaged relief was virtually moved forward to the same extent. In this way, parts of the disappeared rock relief were virtually rebuilt. The results of this study showed that by measuring the gradual and continuous erosion factors and determining the extent of damage, the original shape of the damaged rock reliefs could somehow be reconstructed.     

Biotechnology for Preventive Conservation: Development of Bionanomaterials for Antimicrobial Coating of Outdoor Sculptures

ABSTRACT

Outdoor sculptures are part of the sociocultural identity of cities, but are extremely vulnerable to deterioration due to exposure to harsh environmental conditions and climate change. Furthermore, deterioration by micro-organisms renders urgent the need to design protective coatings. This research proposes an integrated methodology for the development of innovative and sustainable nanofilms for applications in the area of art conservation, very specifically in the preventive conservation of outdoor sculptures. Gathering objective data for the characterization of the surface microbiota is important in order to design strategies that make use of bio or nanotechnology innovative coatings. Methodologies for the characterization of the microbiota present in a granite outdoor sculpture, followed by preliminary results on the application of protective antimicrobial coatings for surfaces of cultural objects are described.     

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.