Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI® dosimetry

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air pollutants is less often measured or included in risk assessment. The MEMORI^® technology presented in this paper was developed as a tool for easy measurement and assessment of the general risk of degradation of heritage objects situated indoors due to indoor exposure to air pollutants. MEMORI dosimetry was performed in locations belonging to English Heritage and Tate (both located in London) and the National Archives of Norway in Oslo, to assess air quality. The related damage risk for collection objects and the protection offered by display and storage designs was assessed. A high level of acidic effect was observed inside a number of showcases, and a high level of oxidizing effect was observed in some room locations. Relatively simple mitigation measures, such as constructing tightly sealed showcases using low emitting materials, installing active carbon absorbing media inside a ‘microclimate’ frame, and using cardboard storage boxes for paper, significantly improved air quality. Overall, implementation of such measures is likely to improve the preservation of objects and reduce conservation costs.     

Pollution monitoring at heritage sites in developing and emerging economies

Abstract

Air quality is an important factor in the preservation of cultural heritage. Systematic air quality assessment is a requirement in most heritage conservation plans. However, apart from temperature and relative humidity, air pollution, which is another air quality parameter, is less often monitored. This is the case especially, but not only, in developing and emerging economies where the lack of air pollution data is worrying. In this paper, issues with air pollution monitoring at heritage sites in developing and emerging economies, from management to technical, are reviewed. Questionnaire responses from over 20 sites in Africa, Asia, and Latin America reveal that about eight out of ten sites have not yet considered pollution data. The responses also show that cost is not the only obstacle but that lack of awareness and insufficient technical expertise are also significant issues. Different possible solutions are reviewed and their appropriateness discussed. They range from systematic monitoring to model-based estimations. Diffusion tube measurements of sulphur dioxide, nitrogen dioxide, and ozone from 11 sites are reported and discussed.     

Integrated and Predictive Systems for Preventive Conservation

ABSTRACT

Forecasting the dynamics of alteration in materials, in particular the timescale of degradation, is relevant to preventive conservation, and great deal of effort has gone into developing new models for the kinetics of physical and chemical phenomena affecting materials. Creating monitoring systems able to assess the evolution of degradation processes that inform intervention programs is necessary to ensure the protection of historical and artistic heritage. The Research Unit for Integrated and Predictive Systems (SIP) is presented: it develops new tools and algorithms to study the alteration of materials using non-invasive techniques and passive monitoring, as well as new mathematical models to predict how the surfaces of materials degrade with time. The paper focuses on the Arch of Augustus and presents initial results from two virtual sensors used to ‘monitor’ environmental conditions outdoors. These systems do not need a permanent, invasive network of sensors in situ. They rely instead on local infrastructure for measuring air quality, and adopt smart information fusion algorithms to predict the environment around the cultural heritage site. Virtual sensors can provide an effective control system that highlights specific conditions linked to specific forms of alteration.     

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.     

Chemical air filtration in archives and libraries reconsidered

The implementation of chemical filtration in air-conditioning systems in archive and library repositories has become standard practice for heritage institutions in many countries. This practice is codified in official standards with general reference to a substantial body of scientific publications on the effects of air pollutants on paper materials. In this paper we report the application of a well-established decision analysis approach elaborating an integral cost-benefit perspective to provide decision support to four European national heritage institutions confronted with dilemmas in connection to chemical air filtration. Available scientific evidence for air pollution induced damage of paper material is reviewed and weighed against financial and environmental costs of air pollution control. Exposure of paper to both indoor and outdoor generated air pollutants at typical concentration levels observed within storage areas is expected to cause minimal to no additional yellowing and embrittlement, while the costs of chemical air filtration are significant. From a cost-benefit perspective the use of chemical air filtration in typical library and archive repositories is therefore discouraged.     

Large-scale assessment of light-induced color change in air and anoxic environments

Abstract

A wide-ranging sample set consisting of dry pigments, dyed textiles, organic and aniline-based dyes, gouaches and watercolors, fluorescent inks, and natural history specimens was exposed to light in air (20.9% oxygen) and near-anoxic environments. After a light dosage of approximately 17.5 Mlux-hours under controlled temperature and humidity conditions, 113 of 125 samples (90% of the sample set) were shown to exhibit less color change in a low-oxygen environment compared with its behavior in air. Thirty-nine percent of this subset displayed color change in anoxia that was between two and four times lower than that observed in air, whereas 47% showed color change in anoxia reduced by a factor of four or more. In contrast, six samples exhibited greater color change in anoxia than in air – these samples included Prussian blue watercolor (three samples), Antwerp blue watercolor, Verdigris dry pigment, and Fluorescent Yellow Winsor & Newton Gouache. Although the results from this small sample subset may cause concern when considering the use of anoxia in the conservation of cultural heritage, particularly for colorant systems whose behavior in anoxia has not yet been identified, this study demonstrates the overwhelming benefits of anoxic light exposure for the vast majority of samples investigated here.     

Understanding storage environmental stability during power outages: A key issue in sub-tropical climates

Efficient air-conditioning systems facilitate climate control in modern museums, libraries, and archives. The climate in Hong Kong is typically hot and humid, so the survival of collections is highly dependent on 24-hour air-conditioning systems to maintain the desired environment in repositories of archives and books, or artefact stores. The continuous operation of such systems in turn relies on a number of factors, such as uninterrupted electricity supply, an active maintenance programme, daily monitoring of their performance and quick response to irregularities as well as backup or alternative systems to support the air-conditioning load in case they are down for servicing. From the risk management point of view, unlike the latter four factors, electricity supply is an external factor that cannot be guaranteed. Fluctuation in the power level that results in stoppage of air-conditioning equipment is not uncommon even in well-developed countries. Long power outages could be catastrophic as they might lead to irreversible damage to collection items as a result of fast, large, changes in temperature and relative humidity (RH) towards the external environment if the air-tightness or hygrothermal stability of the storage are not good enough. Understanding storage environmental stability, especially during electrical power disruptions, is an essential part of the preservation measures and disaster preparedness necessary to protect valuable collections in cultural heritage institutions in the region.     

Effect of Light on Modern Digital Prints - Photographs and Documents

Abstract

This project examines the lightfastness of prints created with the most commonly used digital technologies (inkjet, color electrophotography, dye sublimation and digital press) along with prints created using traditional technologies (color photography, black-and-white electrophotography and offset lithography). The inclusion of traditional prints provides benchmarks for collection care professionals to better gauge the significance of the results. In this study, prints were subjected to two types of lighting used independently to simulate daylight through window glass and artificial indoor illumination. Five aspects of light damage were assessed: fade in the mid-tone neutral, fade in the darkest neutral tone, paper yellowing, changes in paper gloss and text readability. In general, digital prints were less sensitive to light than traditional prints; but each digital printing technology produced at least one sample that performed worse than its traditional benchmark in at least one of the aspects of light damage studied. Therefore, it is recommended that cultural heritage institutions strive to provide the most benign environment possible, taking display practices currently in use for traditional prints as a minimum starting point for the care of digital prints. Close monitoring for signs of change is also recommended.     

数字图书馆在非物质文化遗产保护中的价值及版权问题研究

我国许多珍贵的非物质文化遗产正在逐渐变得鲜为人知,甚至遭遇濒临灭绝的危险。鉴于这种状况,图书馆应该承担起保护非物质文化遗产的责任。但是,数字图书馆在数字化存储、网络化传播非物质文化遗产等过程中不可避免地要牵涉到非物质文化遗产持有人或传承人的版权问题。基于此,文章分析了数字图书馆在非物质文化遗产保护中的价值和其中的版权问题,并提出了数字图书馆遵循的原则、建立土著文化协议和利用特别权利保护非物质文化遗产的版权策略,以期激起数字图书馆保护非物质文化遗产的职责意识,并推动非物质文化遗产保护立法的出台。     

Removal of Organic Acids from Indoor Air in Museum Storage Rooms by Active and Passive Sorption Techniques

ABSTRACT

Adsorbent materials can be used for the removal of organic acids from air in storage rooms with heritage collections. The organic acid removal efficiency of two commercially available activated carbon air-filters were tested in situ in two unoccupied stores with densely packed collections. One filter was designed for outdoor type pollutants (Filter A), while the other was designed for organic acids in indoor air (Filter B). Furthermore, the acetic acid removal efficiency of a desiccant silica gel rotor used for dehumidification was measured in a laboratory at different relative humidity levels. Finally, passive removal of acetic acid by silica gel and unfired clay brick were tested in a chamber, and for clay brick at room level as well. Filter B had the highest removal efficiency. The removal efficiency of both filter types depended on the airflow and the filter performance varied considerably in situ from the values reported from standard laboratory tests. Increasing the filter airflow reduced the removal efficiency from 77% and down to 7% for Filter A, and from 92% to 24% for Filter B. There was almost no effect of active air filtration on the concentration of organic acids when this was measured in the middle and in the corner of the storage rooms away from the ventilation inlets. The desiccant dehumidifier removed 98–100% of the acetic acid from the air, independently of the relative humidity. The desiccant rotor will, however, only be running when there is a need for dehumidification and as a result will only periodically remove pollutants. The high acid removal efficiency by dry silica gel was furthermore demonstrated in a chamber test. A clay brick wall in a test room established a concentration gradient across the room and reduced the concentration of organic acids by 56% compared to close to the emission source.     

An investigation into the cause of corrosion on indoor bronze sculpture

Abstract

Corrosion noted on a number of nineteenth and twentieth century indoor bronze sculptures in the collection of the National Gallery of Canada was the cause for a major condition survey of its Canadian, American, and European bronzes. The results led to a comprehensive study, which included material analysis. This article outlines the steps undertaken to determine the extent and type of corrosion, its possible cause(s), and potential remediation. The survey included 136 bronzes, of which 40 were selected for an in-depth study. Indoor air quality tests of the current building, housing the collection since 1988, were carried out. The dossiers and database records of the selected sculptures were reviewed to investigate their condition, treatment, and storage history. The metal, patina, and corrosion products were subjected to analysis. More areas of corrosion were generally associated with predominantly green patinas and chloride-containing compounds identified in either patina or corrosion samples. The most frequently identified compounds in the patina samples were atacamite, a copper(II) chloride hydroxide, and cuprite, a copper(I) oxide. The most frequently identified compounds in the corrosion samples were atacamite and rouaite, a copper(II) hydroxide nitrate. The analysis determined that the current environment is not contributing to the surface alterations of the sculptures; however, past storage conditions, chemical residues from artificial patination, and likely casting residues are the main causes of the current condition.     

图书馆保护非物质文化遗产优势分析

当前非物质文化遗产保护面临诸多问题.作为传承人类历史文明的主体,图书馆拥有丰富的资源、系统的理论方法研究机制以及成熟稳定的资源管理机制.明确并发挥自身优势,积极参与非物质文化遗产的搜集整理、数字化存贮研究、开发利用和宣传弘扬,是图书馆应有的文化自觉.     

When Glass and Metal Corrode Together,VI: Chalconatronite

ABSTRACT

Chalconatronite, Na₂[Cu(CO₃)]₂·3H₂O, is formed as a corrosion product when copper alloys are exposed to sodium carbonate solutions in the air. This also happens when metals come into contact with corroding soda glass which forms alkaline surface films in reaction with humidity from clean air. More often, substantial amounts of formaldehyde are present indoors which react to formate via the Cannizzarro reaction and accumulate over time in the films. Twenty cases of chalconatronite (including two mentioned in the literature) are reported as occurring on heritage objects with glass in contact with copper alloys: Baroque reliquaries with set glass gems, enamel on metal (sixteenth century and a modern replica of intentionally unstable composition), Christmas tree glass baubles with wires, glass buttons with metal shanks, a glass figure with a wire support, miners’ lamps, and a glass framed daguerreotype. These confirmed identifications might help conservators in investigating similar cases to shed more light on the formation conditions.     

Building Sípnuuk: A Digital Library,Archives, and Museum for Indigenous Peoples

ABSTRACT

The tribal codes and laws managing the traditional knowledge system of the Karuk people have been passed on to us by the ikxaréeyav, or Spirit People. Regulated through access restrictions and protocols, we have been able to preserve information about all aspects of Karuk life for thousands of years. Yet over the past 160 years, this system has remained unacknowledged by the legal frameworks of Euro-America. Since 2012, however, the Karuk Tribe has been developing the Sípnuuk Digital Library, Archives, and Museum, providing self-representative and culturally appropriate access to, control over, and preservation of Karuk cultural heritage.     

Conceptual Model for the Replacement of the Horn of a Nineteenth Century Phonograph

ABSTRACT

3D printing of missing parts of a cultural heritage artifact opens many possibilities and extends the challenges in the processes of intervention on cultural heritage assets. However, restoring these objects may not only mean the replacement of a missing element from its esthetic point of view, but restoring the function for which objects were created. In these processes, the replica of the object must be exact and of quality, but also specific. In this sense, the presented work is a multi-disciplinary attempt to reproduce the missing horn of a phonograph dated to the late nineteenth century. This phonograph belongs to the collection of the ‘Vicente Miralles Segarra’ Telecommunication Museum of the Universitat Politècnica de València. The objective was to recover its esthetic, didactic, and functional levels, i.e restoring its ability to emit sound. To this end, several models were printed with different materials, and the quality of the recorded sound with the different horns was evaluated, assessing their similarity to that obtained from an original horn.     

Metadata Schema to Facilitate Linked Data for 3D Digital Models of Cultural Heritage Collections: A University of South Florida Libraries Case Study

ABSTRACT

The University of South Florida Libraries house and provide access to a collection of cultural heritage and 3D digital models. In an effort to provide greater access to these collections, a linked data project has been implemented. A metadata schema for the 3D cultural heritage objects which uses linked data is an excellent way to share these collections with other repositories, thus gaining global exposure and access to these valuable resources. This article will share the process of building the 3D cultural heritage metadata model as well as an assessment of the model and recommendations for future linked data projects.     

Environmental conditions for the safeguarding of collections: A background to the current debate on the control of relative humidity and temperature

Conditions of relative humidity (RH) and temperature within museums and buildings holding collections of cultural heritage objects are often maintained around a strictly controlled set point of about 50 ± 5% RH and 20 or 21 ± 2°C to provide safe, stable conditions for hygroscopic artifacts. It has recently been proposed that these ranges should be relaxed to values that are less energy-intensive to maintain while still being safe for the objects in the collection, with the aim of reducing both carbon footprint and energy use. It is also suggested that conditions should be determined by the needs of individual objects and by the local climate of the region, rather than applying overall values across the museum as a whole. This proposal has led to much discussion within the conservation community. The suggested values, a stable humidity within the range 40–60% RH and a stable temperature within the range 16–25°C for most objects, apart from the most vulnerable, are derived from the results of experimental research on the responses of individual materials to particular conditions of RH and temperature, as well as observations of the behaviour of cultural heritage objects in their own environments and on loan. This paper describes briefly the historical and scientific background to the present discussion.     

基于区块链的云南少数民族非遗数字资源系统模型及其建设

将区块链技术应用到云南省非遗数字资源的建设中来有利于少数民族非遗文化的保护,区块链技术的去中心化、集体维护、追溯信源、公开透明等优势无疑给非遗数字资源的建设提供了革新的技术支持,助力非遗文化的保护,通过分析云南省非遗数字资源建设现状,寻求区块链技术与非遗数字资源建设的契合点,提出基于区块链技术的云南少数民族非遗数字资源系统模型,以期为云南省少数民族非遗数字资源建设提供新思路,并有效地保护云南省少数民族非遗数字资源,传承处于消亡边缘的非遗文化。     

基于GIS的传统村落文化建档式保护模型构建

本文以地理信息系统（GIS）的空间地理数据展示平台为基础,结合我国传统村落建档式保护工作开展进程与需求,构建面向公众的国家传统村落文化遗存数据平台基本架构,并提出基于GIS的传统村落文化遗存数据平台,包括前端数据采集、数据平台展示、保护规划系统与后台监控维护四个模块,除具备一般GIS空间地理采集与分析功能外,该平台对接了村落土地规划、生态环境、服装首饰、生产与生活器具、文化活动、风俗习惯与文学艺术七个档案数据库,并建立了传统村落数据可视化分析与数据预警机制。     

数字文化遗产协同治理:逻辑框架、案例审视与实现路径

[目的/意义]随着数字文化遗产日益普遍化,其资源建设、技术赋能、服务供给等亟需通过协同治理实现提质增效。[方法/过程]首先,通过文献研究法,论述数字文化遗产协同治理提出的合理性;其次,采用内容分析法,从论文、政策等文本中析出文化遗产治理中的协同要素,结合数字文化遗产特性构建其协同治理的逻辑框架;最后,借助案例分析法,选取 Europeana项目进行映射分析,验证上述逻辑框架并探讨其实现路径。[结果/结论]数字文化遗产协同治理的逻辑框架主要由主体协同、资源协同、服务协同与技术协同构成,并在实践中有所验证。其实现路径包括:缔造多主体合作网络、创设统一化标准方案、打造各色多元资源服务、提供可操作技术方案。