Decontamination of Biocide Treated Museum Objects of the Swiss National Museum’s Collection by Liquid CO2 Technology

ABSTRACT

A decontamination treatment using liquid CO₂ (li-CO₂) and specifically developed for the requirements of museum objects (Lombardo, T., M. Wörle, V. Hubert, E. Hildbrand, I. Mayer, C. Hinterleitner, U. von Arx. 2020. “Influence of Process Parameters on Chlorinated Biocide Decontamination by li-CO₂ on Artificially Contaminated Model Materials.” Studies in Conservation, in press, doi:10.1080/00393630.2019.1641001) was first tested on model materials of wood (with and without coating), silk, and wool with different dyes, paper, and leather in order to evaluate possible material changes. Then, selected museum objects from the collection of the Swiss National Museum were treated to determine the efficiency of biocide decontamination and any resulting chemical and/or structural changes. Results show that dichlorodiphenyltrichloroethane (DDT), pentachlorophenol (PCP), lindane, and chlorpyrifos were successfully removed. Wool, silk, leather, and non-coated wood did not experience any detectable modifications, while moderate to major modifications were observed in wood coated with shellac and polychromy.     

Portable X-ray fluorescence analysis of pesticides in the textile collection at the German Historical Museum,Berlin

The majority of the objects found in the textiles collection at the German Historical Museum in Berlin have been treated with different biocides at various points in the past. Prior to this study, the presence of organochlorinated pesticides in rooms and storage cabinets had already been proven in an analysis of air samples that employed gas chromatography and mass spectroscopy. To estimate the risks these toxins pose to both collections and museum staff, we conducted a field study with the help of a portable X-ray fluorescence spectrometer. In this study, we present an attempt at a reliable quantitative analysis. In addition to chlorine, other potentially hazardous elements such as lead, arsenic, and mercury were found in the majority of the objects. In some cases, however, it has to be taken into account that the detected elements might have originated from manufacturing processes rather than biocide treatments. Such knowledge is a crucial prerequisite to proper risk prediction.     

Evaluation of disinfection techniques for the conservation of polychrome sculpture in Iberian museums

Abstract

Insect infestation is a serious problem in museum collections in Spain and Latin America. This paper investigates the efficacy of modified atmospheres as an anoxant for museum pests, using wooden objects including polychrome sculptures infested by Cerambycidae and Anobiidae species. Insects of long life cycle have been found to be very resistant to carbon dioxide atmospheres. However, inert gases such as argon and nitrogen used in plastic barrier bags effectively eliminated insects in all stages of development. No chemical alteration was observed in the treated materials, including polychromy. These treatments are in progress in a project for biodeterioration control in countries with both tropical or subtropical and Mediterranean climates.     

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.     

Biological Pest Control of a Biscuit Beetle (Stegobium paniceum) Infestation in an Old Masters Paintings Storage Area

ABSTRACT

We report on biological control of an active infestation by biscuit beetles (Stegobium paniceum) of museum objects (Old Masters paintings) in the storage facilities of the Museum of Fine Arts in Vienna. Because chemical and non-chemical treatment methods would have been very problematic, the release of parasitic wasps (Lariophagus distinguendus) was discussed and accepted by the director of the collection. We released 3000 wasps every month from August 2013 until September 2014 in the two infested storage rooms and monitored the activity of biscuit beetles on sticky blunder traps and light traps, and also by visual inspection. In the insect monitoring of 2014 until 2018 no more biscuit beetles were found in the two storage depositories, showing that the treatment was 100% successful. To our knowledge, this is the first proof of a fully successful biological control of a museum pest using parasitoids only, and also of stored product/food pest, outside a laboratory experimental setup. This biological pest control method allowed avoiding negative side effects such as contamination from treatments with biocides, or costly logistics in case of chemical-free methods.     

The efficiency of chloride extraction from archaeological iron objects using deoxygenated alkaline solutions

Abstract

Chloride-contaminated archaeological iron is unstable and problematic to store and display within museum collections. Reducing its chloride ion content using aqueous desalination followed by storage in controlled relative humidity offers one treatment option. This study reports a quantitative assessment of chloride extraction by aqueous deoxygenated alkaline desalination solutions from 120 individual archaeological iron nails. The three treatment methods comprised alkaline sulphite solution (0.1 M NaOH/0.05 M Na₂SO₃) at room temperature and at 60°C and sodium hydroxide solution (0.1 M) deoxygenated using a nitrogen gas positive pressure system at room temperature. Chloride extraction was monitored using a specific ion meter. The nails were digested after treatment to measure their residual chloride content. A wide range of extraction patterns emerged, with the majority of individual treatments extracting 60–99% of the chloride present. Residual chloride levels for 87% of the objects fell below 1000 ppm and 42% were below 200 ppm. Although no treatment extracted 100% of the chloride in the object, alkaline desalination produced very significant reductions in chloride content. The impact of this on future corrosion of the objects is discussed. This quantitative and statistically viable assessment of deoxygenated desalination treatments provides evidence to support their use in conservation practice, which will impact on procedures for the preservation and management of archaeological heritage.     

Preventive Conservation: People,Objects, Place and Time in the Philippines

ABSTRACT

Preventive conservation, with its origins grounded in the material fabric of cultural material, is in a period of transformation, with numerous practitioners, in and outside of the field of conservation, considering its broader and holistic objectives. The conventional tools for the assertion of preventive conservation principles, namely the assessment and management of risks to cultural material from the ‘ten agents of deterioration’, have a central focus on the primacy of physical materials and degradation, with less clear relationships with people, place, and time in their modelling. With a case study focus on collections in the Philippines, this paper argues for a practice of preventive conservation that incorporates a balanced assessment and broader thinking around the contexts of objects, people, place, and time. The case studies of ecclesiastical Church collections, and museum environments in the Philippines, demonstrate how the interdependency of objects, people, place and time forms a holistic and conceptual preventive conservation framework. Through a cyclic renegotiation of these four parameters, this paper speculates on the gaps and opportunities for an inclusive view of preventive conservation that is current and more sustainable.     

My lost museum: User expectations and motivations for creating personal digital collections on museum websites

The recent development of personal digital collections systems on museum websites has prompted researchers to examine the motivations and expectations of museum visitors as they interact with those systems. Results from an online survey completed by visitors to six different museum websites show that users of personal digital collections systems are primarily motivated by a desire to create simple collections of objects and images, and are less influenced by the more complicated features museums have implemented to encourage user participation. The significance of these findings is explored through a discussion of user expectations and motivations with respect to creating personal digital collections, and an attempt is made to reconcile some of the disparities between the perceptions of survey respondents and the experiences of museum professionals developing and implementing personal digital collections systems.     

Linking webbing clothes moths to infested objects or other food sources in museums

The webbing clothes moth Tineola bisselliella (Hummel, 1823) is one of the most common museum pests and can be found all over the world. The larvae damages objects made of feather, wool, fur, and other keratinaceous materials. Pheromone traps are important tools in integrated pest management, which allow the detection of infestations and evaluation of their extent. Organic-rich dust (detritus) or other materials of animal origin, such as dead birds, can be an alternative food source for the moths. This paper analyzes monitoring data collected with pheromone traps from six different museums in Vienna and Berlin and tries to differentiate between moths resulting from infested objects or moths coming from other food sources, such as organic-rich dust. Annual totals of moths trapped and catch rate (moths per trap) are important guides for selecting appropriate remedial measures. Long-term data (over six years) enabled us to interpret monitoring results and differentiate between active infestation of objects and cleaning or housekeeping problems. However, detailed knowledge of the site and buildings, availability of high-quality food for the larvae, and lack of regular cleaning are also important factors to consider when interpreting the data.     

Can't We All Just Get Along? Pan-Domain Collaboration Through an Innovative Collections Review Project at the Royal College of Surgeons of England

ABSTRACT

Although libraries, archives and museums were historically linked as ‘cabinets of curiosity,’ professionalization within the domains in the 19th century seems to have divided these collections. The creation of different working practices and standards built up barriers between these cultural or ‘information’ objects. However, in recent years there has been a well-developed trend towards pan-domain collaborative work which is slowly re-uniting collections and re-establishing links between the specialists that care for them. This article outlines how a project in the Royal College of Surgeons of England brought the library, archive and museum staff together to create a more collaborative environment which has served to benefit the collections, their users, and the staff themselves.     

Overview of Preventive Conservation Research Work on Seismic Mitigation and Subway Vibration Control in Chengdu Museum of China

ABSTRACT

The 2008 Wenchuan earthquake brought numerous issues to the attention of researchers of seismic mitigation in Chinese museums. After the Wenchuan earthquake, the structural design team of Chengdu Museum conducted a series of research projects on seismic mitigation and subway vibration control design of buildings. These projects included the following topics: optimization of design, numerical simulation of seismic performance, analysis of key technologies for the base isolation structure, in-depth studies on structural vibrations caused by the nearby subway, and proposals for reducing structural vibrations. In 2015, after the superstructure of Chengdu Museum was completed, conservators evaluated the safety of permanent exhibitions under earthquake conditions. Seismic protection devices were installed on the showcases according to the preventive conservation requirements for museum collections. Reinforced measures were used for museum collections according to the methods suggested in the document ‘Specification for seismic protection of museum collection’ (WW/T 0069-2015). The conservators also built a systematic platform for earthquake monitoring for museum collections. Preventive conservation studies on seismic protection and subway vibration control in Chengdu Museum are summarized and forecasted.     

Examination of museum objects by means of video holography

Abstract

A prototype inspection system has been tested which makes use of electronic speckle pattern interferometry with computer image processing, for deformation and stress analysis and for the location and analysis of defects in museum objects. Two different examples have been chosen: a nineteenth-century oil painting on a wood panel and a seventeenth-century enamelled terracotta vase. The method can give quite accurate metrological information; it is also particularly promising for rapid qualitative analysis.     

Microfade Testing for Heritage Institutions: A Canadian Experience

ABSTRACT

Since 2008, the Canadian Conservation Institute (CCI) has provided microfade testing (MFT) as a service to more than 13 Canadian museums, archives, and galleries. In addition to obtaining lightfastness data for objects and collections planned for exhibition, MFT is also used for research and for training. This article summarizes the experiences and practices that arose from the variety of objects tested, the demand for the service, and the lessons learned. These include protocols to ensure reliable and reproducible results with multiple users, ways to report large number of results, and how MFT data are used with the CCI Light Damage Calculator for effective communication of the results with other museum staff for exhibit planning.     

Degradation of cellulose nitrate adhesive

Abstract

An adhesive based on cellulose nitrate has been used in the British Museum for the repair of antiquities since cellulose nitrate plastic was first made commercially available. The use of cellulose nitrate adhesives in conservation has been criticized and for this reason the stability of the adhesive currently in use has been investigated. The properties of artificially aged samples of the adhesive have been compared with those of artificially aged adhesive-grade cellulose nitrate. The results indicate that the degradation of cellulose nitrate is substantially retarded by the plasticizer in the adhesive. Samples of cellulose nitrate adhesive taken from joins in objects where the date of conservation work is known have been analyzed. The results have been compared with the analysis of the artificially aged samples and a relationship between natural and artificial aging of cellulose nitrate adhesive has been established. The results of this investigation indicate that cellulose nitrate adhesives are stable for at least 30 years, and may be extrapolated to suggest a lifetime of 50 to 100 years under museum conditions in a temperate climate.     

When Glass and Metal Corrode Together,V: Sodium Copper Formate

A sodium copper formate, first described in 2002, can also form on copper alloys with sodium originating from soda glass hydrolysis. The frequent occurrence (50% of 250 cases of glass-induced metal corrosion) is due to the presence of formaldehyde emissions in storage and its direct reaction to formate in the alkaline surface films. The compound can be produced without the presence of acetate when chalconatronite or metal coupons immersed in soda solution are exposed to formaldehyde vapours. The crystal structure, derived from X-ray powder diffraction, yielded the sum formula Cu₄Na₄O(HCOO)₈(OH)₂·4H₂O. Except for the absence of acetate in the structure, this is in good agreement with the 2002 publication. To assess which kind of combined glass/metal objects are affected, a number of large museum collections were surveyed. Sodium copper formate was detected as a corrosion product using mainly micro-Raman spectroscopy, for instance, on 18 painted Limoges enamels, eight glass vessels with metal mountings, glass beads on metal wire from 11 bridal crowns, nine Christmas tree balls with wire decoration, 40 pieces of jewellery with glass gems, three daguerreotypes, and one miniature with cover glasses.     

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.     

The Future of Three‐Dimensional Imaging and Museum Applications

Abstract Is it time for all museums to initiate large‐scale 3D digitization programs? We don’t yet know how 3D is going to change, replace, or integrate into current museum experience. Yet the possibilities are being actualized right now. What does 3D mean for museums? Digitizing museum objects in 3D (or the museums themselves, for that matter) with incredible accuracy and realism; examining the inside of a mummy; modeling collections in 3D; retaining virtual copies of vulnerable objects; all these and more already exist in the fast‐changing realm of 3D applications.     

Monitoring Acoustic Emission in an Epidemiological Pilot Study of a Collection of Wooden Objects

ABSTRACT

This experimental program, implemented by the Managing Collection Environment Initiative at the Getty Conservation Institute, has provided data about the response of historic objects to changes in relative humidity (RH). Alongside other less sensitive documentation techniques (visual observation, physical measurements, photography, and 3D scanning), acoustic emission (AE) was monitored for six historic, museum-like wooden objects exposed to gradually increasing RH variations. Quantitative calibration of AE sensors and an anti-correlation measuring scheme to reduce environmental noise allowed the AE system to effectively trace micro-damage development caused by environmentally induced stress. Using an epidemiological approach, with respect to sample selection and experimental protocol, the obtained results can be used to explore the acceptable range of climate fluctuations for museum collections. The study’s well-controlled environmental protocol also allowed for the examination of the concept of ‘proofed fluctuation’ by the analysis of object response to reoccurring conditions.     

Taking Paint Samples for Pigment Analysis in Nineteenth-Century England

ABSTRACT

During the nineteenth century, chemists became increasingly engaged in the conservation treatment of polychrome surfaces. While collaborations between chemists and museum workers in charge of easel painting collections were mostly oriented towards the improvement of conservation practices, the involvement of chemists in the nascent field of archaeology was oriented towards material characterization, such as pigment analysis of polychrome surfaces. Since this type of analysis is destructive and damages the artwork, it could, therefore, be assumed that chemists were in these cases less concerned with the conservation of objects with an archaeological and historical provenance. On the contrary, my new reading of nineteenth-century English primary sources reporting pigment analysis shows that chemists also had ethical concerns about the physical integrity of archaeological objects and their conservation. This is apparent in the process in which paint samples were taken from the artworks for their subsequent analysis.     

Protecting Museum Collections from Vibrations Due to Construction: Vibration Statistics,Limits, Flexibility and Cooperation

ABSTRACT

Vibrations due to heavy construction work continue to be a major concern for museums. Although there has been an increase in research on the effect of vibrations on objects of cultural heritage in recent years, selecting measures to protect collections and remain open during construction work continues to be difficult because of a lack of data on what objects can actually withstand, the complexity of vibration loads, and the uniqueness of each situation. The major renovation of the Central Library in Liverpool, UK, which shared walls with the World Museum and Walker Art Gallery, both of which belong within National Museums Liverpool, showed how museums and other institutions can successfully deal with such situations. An integral approach was taken, beginning with an extensive risk analysis to determine which objects could remain on display, which needed extra protection and regular condition monitoring, and which had to be removed. The museums then negotiated a vibration protocol and action plan with the contractors, including continuous monitoring, and trigger levels requiring consultation or work stoppage. Vibration data were also stored and used for later analysis. This integral approach was successful in protecting the collections on exhibition, with only two incidents of reported damage directly related to vibrations. A combination of museum staff experience, excellent communications with the contractors, and some flexibility in defining vibration limits provided a successful recipe for both museums. The analysis of the vibration data using the basic engineering concept of the Palmgren-Miner rule, supports a more flexible approach to setting vibration limits based on recently published guidelines.