Barry Knight

Abstract This paper describes the successful bulk heat-treatment of wooden artifacts infested with furniture beetle Anobium punctatum and death watch beetle Xestobium rufovillosum, without direct humidity control. A chamber was constructed in a store and equipped with four fan-assisted heaters. Core temperatures of between 52 and 55°C were achieved after heating the chamber for eight hours. The heating and cooling cycles were completed over 23 hours. The relative humidity (RH) remained acceptable, ranging from 43 to 75% depending on the location of the sensors. However, the RH inside three sealed bags containing fragile objects was unacceptably high. Equilibrium moisture content and dimensional movement of one object were measured, indicating minimal movement. All live insects, including furniture beetle and death watch beetle in the infested timbers, were killed by the treatment.

In recent years, there has been an increasing amount of interest in the problem of dust deposition in museums. This has mainly been generated by large building projects, for instance at the V&A (Ford 1997), the British Museum (Kibrya 1999) and the Museum of Scotland (Eremin, Adams & Tate 2000). These surveys have mostly been carried out using the "loss of gloss" method developed by Adams (Adams 1997), a very simple technique which measures the decrease in reflectance of ordinary glass microscope slides after exposure to a dusty environment.

The display cases for the Wernher Collection (Ranger's House, Greenwich, UK) had to safeguard the collection within specific environmental parameters that could not be guaranteed within the rooms of a historic house. The cases had to protect the collection from adverse relative humidity, temperature and light whilst still evoking the atmosphere of Sir Julius Wernher's original display. A method of concealing Art-Sorb R cassettes beneath specially designed display plinths was developed in preference to drawers located underneath the case. The main benefit of this method was the greater ease of sealing the display cases, although this necessitated disturbance of the internal case volume to change the Art-Sorb. By limiting the air ingress to one air change per 24 hours, the Art-Sorb should continue to be effective for 6-1 2 months before reconditioning is necessary. All case specifications were rigorously enforced by on-site supervision and by individual testing during installation to ensure an effectively constructed case. Having the facility for continuous monitoring of the rooms and individual cases also enabled any outstanding issues to be identified and rectified to improve the performance further.

This paper describes the successful bulk heat-treatment of wooden artifacts infested with furniture beetle Anobium punctatum and death watch beetle Xestobium rufovillosum, without direct humidity control. A chamber was constructed in a store and equipped with four fan-assisted heaters. Core temperatures of between 52 and 55°C were achieved after heating the chamber for eight hours. The heating and cooling cycles were completed over 23 hours. The relative humidity (RH) remained acceptable, ranging from 43 to 75% depending on the location of the sensors. However, the RH inside three sealed bags containing fragile objects was unacceptably high. Equilibrium moisture content and dimensional movement of one object were measured, indicating minimal movement. All live insects, including furniture beetle and death watch beetle in the infested timbers, were killed by the treatment.

In order to assess the risk to museum collections from their environment, we need to combine information on the strength of historic materials and on the response of historic artefacts to their environment with information on the frequency of extreme climatic events that might cause damage. This paper illustrates one approach to predicting the frequency of potentially damaging events from the analysis of environmental data.

To conserve books, manuscripts and other examples of written heritage for future generations, it is vital to understand how they respond to changes in local conditions; this knowledge also allows informed decisions on appropriate and achievable efficient environmental control to be made. To facilitate this understanding, the rates at which whole books, as well as paper and board, absorb and release moisture have been measured using a variety of complementary techniques. This has enabled the behaviour of these objects and materials to be investigated: it is apparent that the bulk interior of books, particularly in shelved collections, responds very slowly to external variations in humidity (to the point of being largely insensitive to short-term fluctuations); conversely, when considered individually, the component materials exhibit rapid changes (and similar behaviour will be observed at the exposed surfaces of books). The data also suggest that the moisture uptake observed in these experiments is a two-stage process with an initial, relatively rapid absorption phase at the surface and a constant but slow diffusion phase, which dominates over the longer term. This self-buffering has important implications when considering the necessity for highly stable and constantly maintained collection conditions, and may permit the development of more efficient and cost effective strategies.

Window lead is commonly found on mediaeval and post-mediaeval religious and secular sites. It can provide interesting information on the methods of manufacture and occasionally the name of the maker with dates. It should therefore be preserved with more care than is usual. Different methods of manufacture are described (with drawings) and references given to inscriptions on window lead.

The way in which relative humidity affects the rate of degradation of cellulose in paper has been studied by several authors, and several equations relating the rate to the relative humidity have been proposed. This paper examines the data critically, and concludes that there is not yet enough evidence to be able to choose unequivocally between linear, exponential or power law relationships. This has implications for the extrapolation of the results of accelerated aging experiments to normal library storage conditions. 1 Introduction Accelerated aging is a powerful tool for predicting the effect of the environment on the rate of deterioration of collections. The Arrhenius equation is used to extrapolate the rate of deterioration at room temperature from experiments carried out at higher temperatures, where the rate of reaction is great enough to be measurable in a reasonable length of time. The rate of deterioration of paper is affected by the relative humidity (RH) as well as the t...

The lid of a small wooden box, believed to have contained the heart of Abbot Roger de Norton (d. 1291), was discovered in 1872, during the restoration of St. Albans Abbey. The lid has an Arabic inscription that has not previously been translated. It is now suggested that the inscription reads al-ʿizz al-dāʾim wa ’l-iqbāl lahu, or “Everlasting glory and good fortune for him.”

The response of a piece of historic furniture exposed to natural fluctuations in the ambient temperature and relative humidity (RH) has been determined, using a minimally intrusive displacement sensor. Changes in the width of a previously existing crack were monitored and were found to follow changes in relative humidity closely. The cross-correlation function of the crack width and the RH was calculated, and showed that the crack width followed the RH with a time lag of approximately 41 hours. The object hardly responded at all to more rapid fluctuations.

A database of historic paper properties was developed using 729 samples of European origin (1350–1990), analysed for acidity, degree or polymerisation (DP), molecular weight of cellulose, grammage, tensile strength, as well as contents of ash, aluminium, carbonyl groups, rosin, protein, lignin and fibre furnish. Using Spearman’s rank correlation coefficient and principal component analysis, the data were examined with respect to methods of manufacture, as well as chemical stability of paper. Novel patterns emerged related to loss of DP and accumulation of carbonyl groups and acidity with time and the role of lignin and rosin, as well as rate of degradation (k = 10−5 year−1) at room conditions. In-depth understanding of long-term degradation of lignin and rosin is needed to better understand the relationships between composition and degradation of historic paper. This study highlights the importance of mining significant volumes of analytical data, and its variability, obtained from ...

Oxidative degradation is one of the main mechanisms of paper decay resulting in physical and chemical changes. As such, it is of major concern for the preservation of our paper-based heritage. Although it is known that the rate of oxidation is slowed under anoxic environments, these conditions are expensive to achieve and maintain for whole collections. This research, in collaboration with the British Library, has evaluated the effect of various reduced-oxygen atmospheres (1-20%) on the kinetics of oxidative degradation, and has shown that significant rate reductions can be achieved. Oxidative reactions in artificially aged paper have been remotely monitored under a range of environments using transition metal redox reactions as colorimetric indicators. Samples of Iron (III) chloride-doped Whatman paper were heat-sealed in food-grade barrier film bags, with VOC absorbent carbon cloths added. The package was flushed with a mixture of oxygen and nitrogen (1-20% oxygen) and exposed to accelerated ageing conditions for up to 105 days. The colorimetric change was measured through the barrier film and monitored every 100h (approx.). As part of the design of their new high density storage facility, the British Library has utilised OxyReduct® technology - a reduced oxygen fire-suppression system (14.8% oxygen). The research has shown that even at these oxygen concentrations, the rate of paper degradation is significantly reduced. These results have implications for future design of large-scale storage for paper-based collections, indicating that fire-suppressant technologies like OxyReduct® may also be used as a preventative tool.

There have been a significant number of developments in the design of archive and library storage over the past two decades. A notable design feature is to create high density, automated facilities similarly used in the commercial warehouse sector. This borrowed technology has been adapted to meet the necessary standards for the storage of paper-based material (BS 5454), notably introducing facilities to aid in preservation quality environmental conditions. The British Library, in response to the demand for increased storage, has built one such facility in Boston Spa. As well as providing storage for 20% of its total collection, the new facility also has a sophisticated building management system that goes beyond simple temperature and relative humidity control. It also offers a reduction in the oxygen content of the atmosphere, one of the major catalysts for decay, as part of the fire suppression system. Like many other institutions the British Library has been renting space from the commercial sector, however these type of buildings have not been designed to meet library or archive storage standards. The Armstrong Gun Factory situated in Woolwich has been used by the British Library as additional storage. Built in 1858, the building offers basic environmental control and as such the collection is at risk to varying environmental conditions which rarely conform to the British standard (BS 5454). The collection housed here has therefore been transferred to the new facility. This presented a unique opportunity to study, and gain an understanding of, how a real collection will respond to moving from a historic building environment to a highly controlled, low oxygen conservation environment.
Ten books containing temperature and humidity recording data loggers were placed within the mass of books in the Woolwich collection. Following equilibration to the environment, the ‘dummy books’ along with the Woolwich collection were transferred to the new facility in Boston Spa where they continue to record until September 2012. The dummy books will record any environmental changes experienced by the collection as they move from one environment to another. There will be over 2 years worth of environmental data which will be analysed along with the data from the building management system.
It has been well documented that temperature and humidity are known environmental influences. This research also hopes to understand the influence of the buffering capacity of the mass of paper on the interaction of the collection with the environment and how this may effect the preservation of the collection. To what extent does the paper mass govern the interaction and even the internal storage conditions? The degradative state of the collection, the average age of the collection, may also influence how it interacts with the environment. Does an ageing collection respond the same as a relatively newly printed collection? In addition to this the effect of a reduced oxygen environment, and how this influences the collection, is also of interest.
In order to understand the changes influenced by the collection, and quantify said changes, laboratory based investigations are occurring in tandem to the in situ research. The effect of the buffering capacity will be explored by exposing single sheets, and then building up to stacks of books, to varying environmental conditions and measuring the response. The effect of a reduced oxygen environment (between 5 and 15%) on the decay rate of paper is being explored by subjecting paper samples to accelerated ageing conditions (80°C) in a controlled oxygen and humidity environment. Samples are then analysed for pH, colour and mechanical changes. Markers to measure the influence of the environment are also being developed including using moisture sorption as a potential degradation marker.

The Roman Villa at Brading, Isle of Wight, England, was dis-
covered in 1879 and excavated between 1880 and 1884. The
western range of the villa was a corridor house with 12 rooms;
mosaic floors survive in three of the rooms though a further two
were originally tessellated. Since excavation the western range
has been displayed under an iron-framed, corrugated iron clad
building.
The mosaics have an extensive iconography including, among
others, Orpheus (entrance hall), Abraxas (room 2), Perseus and
Andromeda, Medusa, Ceres and Triptolemus, Lycurgus attacking
Ambrosia, and a figure described as an astronomer (room 12).
There is a geometric design in room 11. Although there has been
some limited reconstruction of the mosaics they have not been
lifted and until recently remained essentially as found.
Recently concern has been expressed about continuing disruption of the mosaics, particularly the almost complete floor in
the double-chambered room 12 in which linear bulges have
developed; in the corridor there has been extensive deterioration
of some of the tesserae making up the geometric design. Two
major flooding incidents have occurred in the past few years,
necessitating lengthy cleaning programmes which have highlighted
the extent of the deterioration.
English Heritage has now embarked on a major programme to
stabilize the Villa and its surroundings and to develop a strategy
to allow the mosaics and walls to be preserved in situ.This work
has involved the installation of a drainage system to divert water
running down the hillside, and a survey of drains installed in the
Victorian period. Within the Villa cover building the relative
humidity and temperature are being monitored, as is the soil
moisture. A radar survey has been undertaken to assess the extent
of delamination of tile tesserae from the bedding and to assess the
condition of the bedding layers. A detailed condition survey of
the mosaic has been completed.
In the spring of 1996 a first conservation campaign will be
undertaken. The poster reports the results of the investigatory
work and the 1996 conservation campaign. It is hoped that the
work at the Villa will be a valuable contribution to the establishment of
principles for in situ preservation of archaeological
remains.

... Author: Knight, Barry Title Article/Chapter: "Excavated window glass: a neglected resource?" Title of Source: Archaeological conservation and its consequences: preprints of the contributions to the Copenhagen congress, 26-30 August 1996 Publisher/Distributor: International ...

... S. Lowden, H. Finlayson, TB Brand, E. Willerslev, P. Rowley‐Conwy, L. Andersson and A. Cooper, 'Worldwide Phylogeography of Wild Boar Reveals Multiple Centres of Pig Domestication', Science 307, no. 5715 (2005): 1618–21; G. Larson, U. Albarella, K. Dobney, P. Rowley ...

Parchments comprise one of the most common and valuable sources of archaeological and historical data. Previous studies have shown that parchment also preserves genetic data. These data could be valuable for population studies, to understand past animal husbandry, the development of breeds and varieties and to comment on the provenance of parchments. To improve our understanding of DNA contained in contained in parchments, we analysed genetic data, including both mitochondrial and autosomal loci, from 18th to 19th century English parchments which stable isotope analysis had indicated were well-preserved. DNA results were unexpected. All but one of the parchments produced multiple sequences matching several different species. Ion beam analysis ruled out surface treatments of the parchments (including ink and animal glues) as the origin of these multiple sequences. Our results suggest that the DNA content of parchment is more complex than previous research has suggested and that multiple stages of parchment manufacture, treatment and storage are preserved in parchment DNA extracts.

Analytical techniques are increasingly used to support the work of conservators, providing valuable information about the composition, construction and condition of heritage artefacts, their environments and the interaction between the two. However, this information is often generated in forms which are not necessarily easy to apply directly, as it is expressed in technical or quantitative terms which are not readily interpreted without specialist knowledge. This means that, in many cases, analytical data derived from objects do not provide conservators with useful information for selecting, prioritising and optimally treating objects, or in optimising preventive strategies. One of the roles of the conservation scientist is to facilitate this interpretation of data, and the work presented here outlines approaches which have been developed at the British Library to allow such information to be expressed in ways which can be directly applied by a conservator, drawing on methods used for condition assessments and reports.