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.     

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.     

The Influence of Hygroscopic Materials on the Fluctuation of Relative Humidity in Museums Located in Historical Buildings

ABSTRACT

The preservation of artefacts in museum collections is profoundly affected by fluctuations in temperature and, especially, relative humidity (RH). Since the late nineteenth century, many studies have been carried out on the best way to control hygrothermal conditions. In old buildings located in maritime temperate climate zones (such as Portugal) with strong thermal inertia, and which have low ventilation rate (relative to the volume and number of visitors), daily and seasonal hygroscopic inertia may help to assure the maintenance of RH stabilization conditions. The use of expensive active systems may be minimized through the passive behaviour of internal finishing building materials. This work presents the results of an experimental laboratory study conducted in a flow chamber to demonstrate the enormous potential of hygroscopic materials in stabilizing interior relative humidity. Based in these results and in-situ monitoring in a museum housed in a building, located in Porto, with a typical construction of the 1950s (granite masonry and reinforced concrete slabs), a numerical analysis was done to quantify the influence of hygroscopic materials in stabilizing the interior relative humidity.     

Monitoring and Mitigating Particulate Matter Deposition on Decorative Surfaces: Current and Future Approaches in the Palace of Westminster

ABSTRACT

Research into dust deposition rates on the wall paintings in the State Apartments at the Palace of Westminster, London, UK, began during the restoration of the encaustic floor tiles. The study has broadened to inform day-to-day preventive care for the extensive fine art collections on display and the intricately decorated Gothic interiors, providing a powerful tool for the forthcoming restoration and renewal of the Palace. Different monitoring methods, using optical microscopy, macro-photography and software-based image analysis, were investigated. Qualitative analysis with SEM-EDX and optical microscopy allowed the identification of a number of anthropogenic, geogenic and biological sources of particulate matter, while quantitative results elucidated deposition trends, highlighting both seasonal and works-related impacts. Results indicated that mitigation measures taken to protect works of art and limit the diffusion and deposition of particulate matter on surrounding surfaces were successful. A new dust monitoring method, based on imaging of vertical surfaces and on a recently developed image analysis workflow (CHIJ) operated in open-source software (ImageJ) was trialled alongside more traditional methods for measuring dust deposition through collection of particulate matter on proxies. Results showed significant discrepancies between data acquired directly on wall painting surfaces as compared to horizontal glass slides. The advantages, limitations and complementarity of both monitoring methods were identified, and their potential contributions to the development of data-driven conservation approaches for heritage sites were assessed. The relatively low-tech methods and equipment used present useful and adapted tools for collection managers and conservators to inform their decision-making processes.     

Diagnosing Decay Mechanisms at the Porta Nocera Necropolis,Pompeii: The First Step Towards Effective Preventive Conservation

ABSTRACT

Aspects of preventive conservation are central to the long-term preservation of archaeological sites such as Pompeii. Mitigating moisture ingress and its manifold effects on decay mechanisms such as salt degradation are of critical importance when planning durable conservation strategies. A suite of non-destructive techniques was used to diagnose decay mechanisms at an ancient tomb monument at the Porta Nocera Necropolis. Rising damp and salt contamination are shown to be actively contributing to on-going deterioration of the plaster surfaces. An existing shelter is shown to be inadequate in its protection. These initial results are used to inform a more in-depth, long-term survey as well as the design of a holistic preventive strategy.     

After Eighty Years: Experimental Study of Atmospheric Corrosion in the Metallic Dome of Hafez’s tomb,Shiraz, Iran

ABSTRACT

Hafez’s tomb was constructed on the grave of the well-known Iranian poet in Shiraz, in the 1930s. The dome of this monument is made of copper metal and has been exposed to the urban environment for 80 years. In this study, corrosion mechanisms and conservation conditions of the metallic dome of the Hafez’s tomb are investigated by analytical methods including optical microscopy, ICP-MS, SEM-EDX, and X-ray diffraction. The results showed that the dome is constructed from many copper sheets that are hammered to shape the dome. The corrosion products formed on the surface of copper sheets include copper oxide and copper trihydroxichlorides. In fact, the corrosion mechanism occurring in the metallic dome consists of copper oxidation and redeposition of copper II products because of reaction with air pollutants.     

A NOTE ON THE CLEANING OF SHELL INLAY ON ETHNOGRAPHICAL SPECIMENS FROM OCEANIA

Abstract

Problems were encountered when preparing objects from the Pacific islands for exhibition. These specimens were of wood with shell inlay. Cleaning with non-ionic detergent and distilled water had no effect on the dull shell surface; solvents were little better;finally, glass fibre brushes were tried with very good results. Precautions should be taken when using glass fibre brushes; these include the wearing of protective gloves, dust masks, and the provision of a vacuum cleaner to remove fragments of broken glass fibre and dust from the shell surface.     

Public Libraries Development Reconsidered

Abstract

This paper advances a new interpretation of the development and current decline of public libraries in Egypt based on the study of international influences which helped to shape national discourses about development and provided the context for policy making and resource allocation in Egypt. After 1945 UNESCO encouraged fundamental education and the development of public libraries as operational tools of "education for development". Public libraries witnessed remarkable growth, but then, in the late 1960s, the dominant international discourse about development shifted under the influence of dependency theory to emphasize the need for developing countries to develop from within. Information for development became a self-evident requirement, but the new priority displaced public libraries in favor of specialized information systems for decision-makers. Traditionally, public library decline is attributed to local factors and issues of scarcity. In the case of Egypt, however, factors of scarcity are better interpreted as symptoms than as underlying causes of decline. This paper maintains that the current state of decline of public libraries in Egypt is primarily a consequence of public policy choices precipitated by a shift in international as well as national development priorities, not of factors inherent in the country’s political, social and cultural fabric.     

New Perspectives on the Study of Particulate Matter Deposition within Historic Interiors

ABSTRACT

This paper proposes a new way of interpreting particulate matter deposition indoors. The rate of deposition of dust in surfaces is presented as the result of the combination of two main factors: the concentration of suspended particles close to surfaces, and their capacity to deposit, expressed as the deposition velocity. We suggest that either of these two factors can be altered in order to mitigate deposition. The implications of this perspective are explored using in-situ measurements in a historic property (Apsley House, London) and a computational fluid dynamics model of aerosol deposition. The cases studied involve the effect of outdoor wind on the ingress of particles, the consequences of leaving the main door open, and the effects of the ventilation system on deposition. The results demonstrate that simulations can be used reliably to explore hypothetical scenarios or situations that would be experimentally challenging. The inputs and outputs of the computational model are discussed in view of its usability in preventive conservation.     

Climatological analysis in relation to the conservation of a sixteenth-century spanish polychrome wooden ceiling

Abstract

A sixteenth-century Spanish wooden ceiling was installed in the Morning Room of Hearst Castle in the early 1920s. Since that time, the adhesion between the ground/paint layer and its wooden support has weakened considerably. As a first step in designing an effective conservation program, it was necessary to assess the role of the environment in this deterioration process. Air movement patterns, humidity and temperature parameters, air pollutants, and the impact of approximately one million visitors per year on the microclimate were studied over a one-year period. Correlations between the various components of the study were mapped, including CO₂ concentrations vis-à-vis the number of visitors, and humidity and temperature changes in relation to tourists, air circulation patterns and variations in the external climate. As a result of this study, temporary measures were taken to improve the conditions of the immediate environment and proposals were made for more permanent solutions.     

Zinc dust treatment—an effective method for the control of bronze disease on excavated objects

Abstract

Silver oxide is currently used to treat isolated spats of bronze disease, forming a seal of silver chloride. The technique is not infallible: an analytical study showed that the conductive properties of the silver chloride seal, together with the comparatively poor moisture barrier formed, are the factors responsible for failure. In the new zinc dust treatment proposed, tough, adherent and relatively stable zinc compounds form an improved barrier, effectively sealing the area of bronze disease. Objects treated with zinc dust were subjected to high humidity for several months and afterwards exposed to a tropical humid environment for four to five years. These objects showed no re-emergence of bronze disease whereas repeated use of silver oxide failed to stabilize the objects. The method developed is simple, less time-consuming, and relatively easy to employ.     

Zoo veneers: Animals and ethnic crafts at the san Diego zoo

The author critically examines the juxtaposition of ethnic craft souvenirs with animals at the San Diego Zoo. The deployment of symbolic representations of animals and people at zoos are considered in the specific historical context of San Diego. While animals and people were displayed for tourists at expositions and world's fairs staged in the nineteenth and twentieth centuries, today visitors to the zoo can find representations of exotic cultures and persons in the gift shop. Although ethnic craft souvenirs do not, on first impression, seem out of place to most visitors in the context of the zoo, they present a conceptual problem: What is their relation to either the San Diego Zoo or to the animals displayed there? Both the animals and the ethnic crafts souvenirs, it is argued, contribute to an illusion that there exists a pre‐capitalist sphere untouched by Western colonialism.     

Staging peace: Televised ceremonies of reconciliation

ABSTRACT

The visit of Egypt’s President Anwar Sadat to Jerusalem was the model for Dayan and Katz’s conceptualization of the genre of media events, as live programs which have the power to transform history. Fifteen years later, a series of televised reconciliation ceremonies, which marked the stages of the peace process between Israel and its Arab neighbors (the Palestinians and the Jordanians), are used to re-examine the model. We demonstrate (1) how the effectiveness of these ceremonies depends on the type of contract among the three participants—leaders, broadcasters and public—each of whom displays different kinds of reservations, and (2) how the aura of the ceremonies draws on the prior status of the participants (Hussein), but also confers status (Arafat).     

Wall Coating Using the Escariola Technique

Abstract

This paper is concerned with the rediscovery of a technique of interior wall decoration known as Escariola which was introduced by Austrian and Italian immigrants to the mid-west region of the state of Santa Catarina (southern Brazil) at beginning of the twentieth century. This coating provides a refined, attractive and durable finishing. Historical investigation combined with sample characterization using X-ray diffractometry (XRD) and differential thermal and thermogravimetric analyses (DTA/TGA) revealed that this technique consists of the application on a rendered masonry wall of a 2–3 mm thick layer of slaked lime/white cement paste which is subsequently polished with talcum powder. Samples of Escariola paste were empirically reformulated and tested on a rendered masonry wall. Guidelines for producing Escariola are proposed here.     

I Can See Further Now: Preventive Conservation in a Changing Heritage World

ABSTRACT

Cultural heritage has undergone a paradigm shift in recent decades. Museums in particular have changed from being a house of treasures to be admired by visitors, to being a place where objects provide the context for new interpretations. Today, visitors are provided with an opportunity to participate and co-create meaning. At the same time a UK government requirement for accountability has pushed the sector towards business management and professionalisation. This new context has forced conservators to respond by aligning themselves with these trends. In order to stay relevant conservators have to take on an active role in facilitating audience participation and increased access to collections, while at the same time improving their efficiency and accountability. Preservation frameworks have played a significant role in enabling conservators to respond to these changed needs within the sector. Crucially, preservation frameworks have encouraged conservation professionals to collaborate with colleagues from across an entire organisation. Having gained a broader understanding of the context within which they work, preservation frameworks have also allowed conservators to systematically collate and analyse data and present these to their stakeholders in a language understood by them. The review of a number of case studies reveals that preservation frameworks help conservators understand the bigger picture and be influential at the right levels.     

A New Hot Table for Relining

Abstract

Two red dyes from 21st dynasty Egypt and one from the 12th dynasty were analyzed. The first two were essentially madder, in one case mixed with small amounts of tannins. The third contained pure haematite (red ochre), thus representing one of the earliest known uses of this pigment for the dyeing of linen.     

From Knowing to Not Knowing: Moving Beyond “Outcomes”

The ways that museums measure the success of their exhibitions reveal their attitudes and values. Are they striving to control visitors so that people will experience what the museum wants? Or are they working to support visitors, who seek to find their own path? The type of approach known as “outcome‐based evaluation” weighs in on the side of control. These outcomes are sometimes codified and limited to some half‐dozen or so “learning objectives” or “impact categories.” In essence, those who follow this approach are committed to creating exhibitions that will tell visitors what they must experience. Yet people come to museums to construct something new and personally meaningful (and perhaps unexpected or unpredictable) for themselves. They come for their own reasons, see the world through their own frameworks, and may resist (and even resent) attempts to shape their experience. How can museums design and evaluate exhibitions that seek to support visitors rather than control them? How can museum professionals cultivate “not knowing” as a motivation for improving what they do?     

汉代墓葬的墓垣类型及相关问题

汉代较多墓葬砌建墓垣用于保护封土,并与丧葬需求相结合,衍生出一些其他功能和作用,内容与内涵也不断丰富。考古发现的汉代墓垣已有相当数量,地域上既有集中也有零星分布,有较多明显特征。汉墓的墓垣一般为1-2重,具体位置、平面形状存在不同,砌筑材料及砌建方式亦有差异,反映出相应的时代特征和发展变化,折射出与墓葬及墓主等级相关的内容。汉墓的墓垣对于辨识原有封土的形状有重要作用,进而可探讨汉代墓葬封土的发展和变化。墓垣与墓地围墙存在差别,具体表现在面积、功用、配套设施及与封土距离远近等方面,文献关于汉墓围墙的记载较多,可能与围墙明显体现墓主身份等级有关,而墓垣相对低矮,较高等级墓葬极少使用是其少见于记载的原因之一。     

Ban Chiang bronzes: manufacturing techniques and restoration

Abstract

Original protective renderings have been the focus of numerous studies in recent years. Relevant literature, archival research and archaeological findings reveal that a number of mortar mixes or liquid substances were brushed on to protect and colour-unify the exterior ashlar-stone of many historic buildings. These coatings were of two types: common mortars, particularly improved with organic additives, and water-resistant filmforming substances. Economic cost, local supply, traditional practices and technological development are vital to an understanding of regional preferences for one mortar mix or material over another. The Cathedral of Leon is a mediaeval gothic temple from the thirteenth century, profusely remodelled throughout its history. In the sixteenth century, a new design of the courtyard partially enclosed a fifteenth-century exterior wall. Samples from the enclosed and exposed parts of this wall were examined. Analytical research suggests that the stone surface of this element received a treatment based on gypsum with organic additives. These organic products were fatty materials of the lipid type (tallow or lard) which reacted to form an insoluble, hydrophobic soap, at the same time providing the stone with its yellowish colour. The exceptional amount oflime registered in samples from the enclosed section has been considered a component of this surface treatment.