Climate control for the passive conservation of the romanesque painted wooden ceiling in the church of Zillis (Switzerland)

Abstract

Extensive investigations of the deterioration of the romanesque painted wooden ceiling in the church of Saint Martin in Zillis (Switzerland) have revealed three major active deterioration phenomena: (1) tented flaking of paint layers; (2) flaking of the wheat starch fixative together with parts of the paint layer; and (3) fungal growth. These deterioration processes correlate with the dynamics of the prevailing room climate. Both forms of flaking are mainly driven by fluctuations of the relative humidity (RH), whereas the fungal attack can be related to high average RH and stagnant air. Frequent daily fluctuations in RH of up to 20% in summer are due to visitors leaving the doors open, while fluctuations of up to 25% are related to heating in winter. Given the risks of new consolidation treatments, the aim is to slow the decay processes by influencing the climate in the room. Installation of automatic door-closers reduced fluctuations but led to a rise in RH and a reduction of air movement, causing greater fungal growth. Subsequently, an automatic air-exchange system triggered by absolute humidity values was installed to reduce excess humidity and to exchange stale air without producing major fluctuations in the relative humidity. This kind of 'climatisation' has the advantage of being highly flexible, allowing variation of the rate and scale of exchange; it is, moreover, truly reversible.     

Decay of softwood in archaeological wooden artifacts

Hardwoods and softwoods were used side by side throughout Egyptian history, and importing softwoods that had an attractive color and texture was common. Over the decades, artifacts based on hardwoods and softwoods underwent deterioration phenomena, sometimes reaching either a level of brittleness or turning into a wood powder that may easily crumble. These levels of decay/degradation are often difficult to handle in terms of conservation treatments. To study or identify the reasons for decay has always been a point of interest for conservation purposes, but to assess decay and choose an appropriate treatment according to the state of preservation for the sake of keeping an artifact intact has become a subject of major importance. It is difficult at times to understand the deterioration process, because hardwoods and softwoods are different in structure, properties, and chemical composition. For this preliminary study, decayed samples from three commonly used softwood types, cypress (Cupressus sp.), cedar (Cedrus sp.), and pine (Pinus sp.), were identified and chosen. Scanning electron microscopy (SEM) of the samples indicated the degree of decay. Decayed and non-aged samples of the same wood type were analyzed using Fourier transform infrared spectroscopy (FTIR), and all the major carbohydrate and lignin bands were recorded. The strong hydrogen bonded (O–H) stretching absorption associated with water linked by hydrogen bonds to the –OH groups of cellulose and hemicelluloses in all decayed samples increased with decay. The brown powdery, fragile samples that had been evidently affected by microbial decay had a higher amount of lignin. The lignin/carbohydrate ratio was calculated and results compared. The increase of either lignin percentage or extractives in some of the samples had caused a darkening of color in both cypress and cedar samples, but the pine sample did not have the same texture and appearance. In cases where the lignin percentage decreased the samples had changed to a slightly lighter color. FTIR results explained the decay phenomena observed in SEM micrographs and helped assess wood decay and also confirmed results that had been previously obtained while applying traditional chemical analysis on wood.     

High-Resolution Ultrasonic Imaging of Artworks with Seismic Interferometry for Their Conservation and Restoration

Artworks are an inseparable part of the cultural heritage of societies and provide us with a unique look at cultural developments through time and space. For the best possible conservation, it is paramount to know the constituent materials, condition, and construction techniques of the objects (e.g. painting on wood, fresco, sculpture). Such information is required not only for the surfaces of the objects, but also for the interiors; in the imaging discipline, this is known as depth imaging. Here, we introduce a new method for non-invasive depth imaging as an alternative to traditional non-invasive methods when the latter cannot be used to obtain the required information. We use ultrasonic transverse-wave transmission measurements and turn them into virtual reflection measurements. We achieve this by applying seismic interferometry with active sources. Obtaining reflection measurements by seismic interferometry allows us to apply an advanced imaging technique – prestack depth migration, as used in seismic exploration – to produce a high-resolution depth image of an object. We apply our method to ultrasonic data recorded on a mockup of a painting on a wooden support. We validate our method by comparing our results with an image from X-ray computed tomography.     

Dubious Early Medieval Jewels from Matzhausen (Bavaria): New Material and Technological Investigations

ABSTRACT

A controversial set of elite jewels assumed to be of early medieval period, recovered in 1937–1938 from a burial site in Matzhausen (northeastern Bavaria) was investigated to determine their technological coherency as well as their authenticity. The discovery of these jewels was exploited by German nationalists to argue that the material culture observed in Bohemia and Moravia in the ninth century had Germanic roots. The circumstances of their discovery, however, remain unclear. Research in archives demonstrated the involvement of the SS Ahnenerbe organisation in the recovery of the jewels. Are these jewels authentic or are they forgeries manufactured or modified by a modern craftsman to serve German expansionist nationalism? Three jewels recovered in the grave – a gombik (hollow spherical pendant), an earring with chainlet, and a zoomorphic figurine – were investigated using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX), X-radiography, and stereomicroscopy. The investigation revealed a very heterogeneous set of objects with respect to technology and state of preservation. It also uncovered repairs and past invasive interventions involving modern metal and solder. Comparison with similar types of jewels from Bohemia and Moravia points to important differences in construction and technology, which confirms the uniqueness of this set of objects and casts suspicion on their authenticity.     

近代报刊白话文化的嬗变趋势与内驱机制

中国近代报刊话语言述方式由文言文转向白话文,是近代中国纸质传媒精英文化向大众文化过渡的表现,主要经历了四个时期,其演变有深刻的历史背景和原因。传播理念的转变、印刷技术的革新和文化观念的突破,是推动中国近代报刊白话文化大众化趋势的内驱力。     

Non-structural injection grouts with reduced water content: Changes induced by the partial substitution of water with alcohol

Conventional grouting – used to stabilise delaminated plaster – typically involves the use of water as suspension medium. Water can be dangerous when water-sensitive original materials are present and can cause the solubilisation of salts, leading to their re-crystallisation on drying. Ethyl alcohol is a less effective solvent for soluble salts and generally does not affect the original materials. This is the reason why it was used as a partial substitute for water in grout preparations in the present research. Three water–ethyl alcohol-based grouts were compared with the correspondent water-based grout. The working properties and performance characteristics of the injection grouts with reduced water content were measured to assess their suitability for use on historic plasters.     

Finding common ground and inherent differences: Artist and community engagement in cultural material and contemporary art conservation

Comparisons are often made between the conservation of cultural material collections, often described as ethnographic, and contemporary art collections, and indeed there are significant parallels. The stewardship of both of these types of collections can challenge traditional tenets of conservation, requiring conservators to ask themselves ‘What are we preserving?’ as preservation extends beyond the physical. The work must be placed in a broader conceptual context and the conservator must seek out those who are deemed to have the most authority – whether it is the artist, the artist's assistants and estate or the source community – to establish this context. Engagement with constituents creates valuable reciprocal relationships, which can benefit the artist, community, and museum. The relationships and the parallel practice of two seemingly disparate fields are examined using examples from the National Museum of the American Indian (NMAI) and the Yale University Art Gallery (YUAG). Conservators at NMAI, a living culture museum containing archeological, historic, and contemporary art collections, are in the unique position of working with community stakeholders with direct ties to historic collections and contemporary artists whose work is actively acquired by the museum. Conservators at YUAG, an encyclopedic museum with a pedagogical directive, are attempting to establish a more rigorous program of artist engagement to direct preservation and understanding of contemporary art collections.     

Technologies for Wood Preservation in Historic Preservation

Because of the abundant forests of the world, wood is one of the most common materials found in historic buildings. Wood is relatively easy to fabricate into beams, columns, and roof systems using simple hand tools. However, because of its biological origin, wood is one of the most complex constructions materials. It is produced by thousands of different species of trees, and each type of wood has unique properties. Wood has an affinity for moisture and this can lead to biological deterioration caused by insects and decay fungi. This chapter presents information on understanding and preventing the mechanisms of wood deterioration in historic buildings. The chapter includes a discussion of wood preservation and technology, including wood finishes and wood preservative treatments, diffusible preservatives, and naturally durable wood species. A brief discussion about the repair of deteriorated timbers in buildings is also included.     

关于"新图书馆运动"的概念

“新图书馆运动”是发生在近代中国图书馆史上的一场具有重大历史意义的事件,目前有图书馆界学者认为这一概念可泛指,有的对这一概念还心存疑虑。如果从开展这场运动的宗旨上加以分析,“新图书馆运动”这一概念确实是最符合实际情况的高度概括。     

Allowable microclimatic variations for painted wood

Abstract

Environmental standards for cultural heritage collections have been much debated in recent years. The interest in the issue has been driven by the growing movement towards green museums, that is, managing indoor museum environments in a responsible and efficient manner, especially in terms of reducing energy consumption and carbon emissions but at the same time maintaining high standards of collection care. Painted wood is among the category of heritage objects most vulnerable to relative humidity and temperature fluctuations. Therefore, scientific understanding of how changes in environmental conditions ultimately affect painted wood is crucial to the development of rational guidelines for the control of climate in museums and historic buildings. This review provides a systematic progression through two fundamental approaches to establish the allowable ranges of climatic variations – an analysis of the mechanical response of painted wood as a complex, multilayer system to climate variations, and an analysis of the historic climate to which the objects have acclimatized. The climate specifications and standards based on both these approaches are reviewed.     

Mineralogical,Chemical, and Thermal Characterizations of Historic Lime Plasters of Thirteenth–Sixteenth-century Daulatabad Fort,India

Iron ore as pozzolanic filler is an uncommon constituent of historic plaster rarely reported in any research. This paper presents one such study from western India where hematite instead of crushed bricks was identified as admixture in thirteenth–sixteenth-century CE Mughal masonry lime works of Daulatabad Fort. The outer/inner coat plasters from different locations of the fort were examined for morphological, mineralogical, chemical, and basic physical properties. The analytical investigative study was performed by optical microscopy, sieve analysis, X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, SEM-EDX, and thermal analyzer. Although the plaster is dominantly made of micritic calcite and aggregate, incorporation of gypsum in the outer and inner coats has been detected and probably acted as a second binder. Cannabis sativa was mixed in the plaster, pointing to the knowledge of hempcrete technology by the makers of Daulatabad Fort. This investigation has now provided essential information with enough precision about this historic plaster for formulation of compatible repair materials essential for the site restoration.     

A Multi Proxy Investigation of Moisture,Salt, and Weathering Dynamics on a Historic Urban Boundary Wall in Oxford,UK

ABSTRACT

Boundary walls are neglected but important parts of historic urban environments, and they are often prone to serious deterioration. Understanding moisture and salt dynamics within boundary walls can help infer the causes and dynamics of deterioration. This investigation investigates the patterns of moisture, salt, and deterioration on a 300 year old limestone boundary wall in Worcester College, Oxford. Multiple methods to assess moisture and salts within and across the wall (electrical resistivity tomography, handheld resistivity-based moisture meter, paper pulp poultices, scanning electron microscopy, inductively coupled plasma optical emission spectrometry, and ion chromatography of small scale sampling of deteriorated limestone) were used in conjunction with decay mapping of both sides of the wall. The salt weathering strongly correlates with severely weathered zones at the wall and salts, mainly sulfates, seem to be the main agent of decay processes. The combined results demonstrate that the environmental influences driving stone decay can differ on a very small scale even at a comparatively simple structure like a boundary wall, and that repairs can have adverse effects if the patterns of salt and moisture dynamics are not sufficiently known.     

清末民政部与近代文物保护事业——兼及主事尚秉和之功迹

光绪三十二年,清政府进行大规模中央官制改革,民政部的设立就是其中的重要内容。民政部是清政府首次设立的专门统筹管理民政事务的机构,其职掌包括全国古迹的保存,具体由营缮司存古科负责。民政部主事尚秉和是存古科掌稿,是相关规章制度的拟定者。在民政部的推动下,清廷先后颁布了城镇乡地方自治章程、民政统计表等,其中都有保存古迹的内容。宣统元年,民政部更是制定了专门的保存古迹推广办法章程,包括调查事项6条和保存事项5条,成为各省保护古迹工作的指导。此时,各地开始执行古迹保护政策,取得了一些成绩,尤其是东南江浙一带。清末民政部制定的保护古迹规章制度在近代文物保护事业中有着重要地位,尤其对民国时期文物保护事业产生了积极影响。     

风雨陶风楼--中国近代图书馆发展的历史见证

19世纪末，在西方列强的冲击下，中西文化交流日益频繁，中国社会各方面摆脱传统的束缚，开始走向现代化。在图书的收藏、阅读、使用、传播方面，延续千年的传统私人藏书楼已不能发挥传播文明，教育民众的作用。在一批官员、学者的积极推动下，中国近代的图书馆事业由此诞生。陶风楼作为中国近代最早的公共图书馆之一，是在清两江总督端方的支持下，由号称“中国近代图书馆之父”的著名历史学家、版本学家、藏书家缪荃孙创建，由著名历史学家、教育家柳诒征振兴发展起来。无论是规模、还是影响，陶风楼堪称中国近代公共图书馆发展的历史见证。     

A new normal? Competing national cultural discourses and workers’ constructions of identity and meaningful work in Norway

We examine how conceptions of identity and meaningful work are influenced by a nation's changing economic and political environment. We collected research in Norway – a country with a rich economy that has heavily relied upon oil production since the 1980s. Yet depleting oil resources are prompting an economic transformation. Twenty-seven interviews and a thematic analysis revealed how Norwegian workers safeguarded their traditional, collective workplace values, yet were simultaneously confronted with modern – more masculinized – workplace performances ushered in with the oil era. We contribute to theory by suggesting that work's meaningfulness is constructed by competing national cultural discourses that evolve over time. These discourses become narratives that citizens draw upon to evaluate work and to negotiate their personal and professional identities.     

UNIVERSITIES,PUBLIC SERVICE RADIO AND THE ‘AMERICAN SYSTEM’ OF COMMERCIAL BROADCASTING, 1921–40

In the second half of the nineteenth century, several Hebrew journals were established, creating a new cross-communal printed public sphere. At the time, Hebrew was merely a language embedded within the two languages of daily communication – spoken Jewish vernacular (Yiddish in Eastern European communities) and the state vernacular. It lacked an active basic vocabulary for many spheres of modern life and was no longer used in everyday or political discussion. In this paper, I investigate the linguistic choice of Hebrew by comparing three of the main nineteenth-century journals – HaMaggid, HaMelitz and HaTzfira. The reasons for using Hebrew were distinct and individual for each journal. Yet, I argue that choosing Hebrew had more indirect, national repercussions: even when it was not the primary rationale for its use, journalistic Hebrew acted as a catalyst for the rise of modern Jewish nationalism.     

Algorithms: avoiding the implementation of institutional biases

ABSTRACT

Computer algorithms, the logic and code that power automated decision-making programs, increasingly dominate many aspects of modern society. There are already many examples of institutional biases – including ideological bias, racism, sexism, ableism – being solidified in algorithms, causing harm to already underprivileged populations. This article explores library-specific and society-wide examples as well as efforts to prevent the implementation of these biases in the future.     

Investigating salt decay of stone materials related to the environment,a case study in the St. James church in Liège,Belgium

Salt crystallization is recognized as a major cause of damage to porous building materials, threatening the sustainable preservation of our valuable built heritage. Unfortunately, the crystallization behavior of the detected salt mixtures is complex and not fully understood. While the deliquescence points of single salts are well documented, this is not the case for salts in a mixture where one is confronted with the presence of different cations and anions. In this paper the salt content of the murals and the limestone tracery of the main entrance porch from the sixteenth century church of St. James in Liège, Belgium is investigated and related to the climatic conditions of its environment. Concerning the salt load, the research consists of hygroscopic moisture content measurements, quantitative ion analyses, and the prediction of phase equilibria using the thermodynamic model ECOS/RUNSALT. This model can predict the salt crystallization sequences of a particular ion mixture. The output is mathematically evaluated with collected temperature and relative humidity data, which enables the calculation of the number of salt crystallization–deliquescence cycles. The results show that even small amounts of salts can cause damage over a long period of time when the environment causes frequent cycles of crystallization–deliquescence over time. It is shown how a mixture of small amounts of (double) salts, including hygroscopic ones, can have a significant effect on the decay of historic building materials in the case of daily changing climatic conditions and periods of extreme drought. As a result, the crystallization of double salts and hygroscopic salts such as calcium nitrate cannot be ignored. The scientific method and the results are described.     

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.     

Identification of white efflorescence on wooden African objects

This article describes the investigation of white efflorescence on eight wooden African objects from Malawi and Zambia and the treatment of the objects to remove the deposits. The source of the efflorescence on these objects was determined to be the heartwood from which they were carved. Using gas chromatography-mass spectrometry and Fourier transform infrared spectrometry, the crystalline efflorescence was found to consist of homopterocarpin and pterocarpin, two isoflavonoid compounds found in woods and shrubs belonging to the genus Pterocarpus, and African Baphida nitida. The crystal growth appeared to be heaviest on areas of the objects that were more deeply carved as well as on those objects without a surface finish. The storage conditions of the collection were studied and found to have likely accelerated the rate and extent of the natural movement of the pterocarpan compounds from the interior of the heartwood to the outer surfaces.