Conservation Science

391 Pages·2009·5.41 MB·English

Conservation Science
Heritage Materials

Conservation Science
Heritage Materials
Edited by
EricMay
School of Biological Sciences,University of Portsmouth,
Portsmouth,UK
MarkJones
The Mary Rose Trust,HM Naval Base,Portsmouth,UK
ISBN-10: 0-85404-659-3
ISBN-13: 978-0-85404-659-1
A catalogue record for this book is available from the British Library
© The Royal Society of Chemistry 2006
All rights reserved
Apart from fair dealing for the purposes of researchfor non-commercial purposes or for
private study,criticism or review,as permitted under the Copyright,Designs and Patents Act
1988and the Copyright and Related Rights Regulations 2003,this publication may not be
reproduced,stored or transmitted,in any form or by any means,without the prior permission
in writing of The Royal Society of Chemistry,or in the case of reproduction in accordance
with the terms of licences issued by the Copyright Licensing Agency in the UK,or in
accordance with the terms of the licences issued by the appropriate Reproduction Rights
Organization outside the UK. Enquiries concerning reproduction outside the terms stated
here should be sent to The Royal Society of Chemistry at the address printed on this page.
Published by The Royal Society of Chemistry,
Thomas Graham House, Science Park, Milton Road,
Cambridge CB4 0WF, UK
Registered Charity Number 207890
For further information see our web site at www.rsc.org
Typeset by Macmillan India Ltd, Bangalore, India
Printed by Henry Ling Ltd, Dorchester, Dorset, UK
Preface
Conservation science is a broad church and a rapidly developing discipline.The
aim of this book is to provide, in one volume, an account of the composition
and conservation of historic materials. It brings together recent information on
decay and degradation that are unusually scattered in journals and not readily
available to many practising conservators. By doing this, it is hoped that the
potential of materials conservation, together with the processes that are neces-
saryto maximise it, can be made more understandable to all those interested
in historic objects. We believe that a clear understanding of the deterioration
mechanisms of historic and artistic works will help conservators make informed
decisions about their care and treatment.
At the time of writing, there is concern throughout Europe about the frag-
mented nature of research funding in conservation science, despite the fact
that heritage generates considerable income through tourism for national
economies. There is parliamentary activity at national and EU levels as we
move to the 7th European Research Framework. This book demonstrates that
a very wide range of accumulated deterioration problems affect materials that
are part of our movable and immovable heritage. The threat of environmental
climate change now compounds those problems and seriously extends the
scale and nature of the challenge that conservators and conservation scientists
face. The wealth of knowledge offered by specialists in this book illustrates
the commitment to good science and reinforces the need for on-going research
to meet the new challenges.
The book is intended for graduates and professionals who are involved in
the understanding and care of historic materials, whether conservators, finds
specialists, museum curators or administrators. It is also of interest to under-
graduates studying archaeological conservation at university, or scientists taking
subsidiary courses in conservation. It should also prove useful to those involved
in the training of students in material conservation. Inevitably, when describing
deterioration (decay), material composition and treatment methods, science
is essential for the explanation. However, the general reader with basic science
knowledge should have no difficulty in following the text. It should provide a
vi Preface
good introduction to the subject and we hope that it will be a valuable reference
work and precious reading companion for both students and professionals.
The text is divided into chapters covering analytical aspects, organic materi-
als,inorganic materials, wall paintings and in situpreservation. Contributions
are from a wide range of practising international experts from leading research
institutes who outline the problems and provide many interesting and excit-
ing case studies. The text offers a basic introduction to the science of heritage
materials, their deterioration and restoration processes. The complexities and
problems faced by conservators and scientists are addressed together with the
processes of decay and degradation that affect ancient materials. It describes
in detail the processes of decay and degradation for each major category of
material (paper, wood, stone, glass, metals, leather, plastics etc.). The chapters
on plastics and in situconservation provide insights into the rapidly developing
new areas of conservation science.
A word here about topic coverage and our policy on referencing. These are
generally full with topics where there exists no adequate books or review
articles – metals and wood are cases in point – and, as a consequence, there is
no necessary correlation between length of a chapter and the practical impor-
tance of the subject. In relation to the references, we have adopted a non-
referenced style and provided reference sources and further reading at the end.
This book is clearly the product of many specialists and the editors are con-
scious that without their input it would not exist. It has had a very long gestation
period. There is never a good time to edit a book; it is a labour of love that sur-
passesall understanding and common sense, measured against the increasing
pressures of academic life. The contributions have come in over a long period
and in that sense we are grateful for the understanding of not only the authors,
but the RSC, particularly Janet Freshwater and Annie Jacob, who have cajoled,
but mostly supported, us throughout a prolonged delivery. We are also grateful
for assistance and help from our organisations, namely, the Mary Rose Trust
(MJ) (notably Andy Elkerton with the index) and the University of Portsmouth
(EM). This could not have happened without the support of our families,
especially Helen and Jeannette. We hope you enjoy the final product.
Eric May
Mark Jones
May 2006
Contents
Chapter 1 Introduction 1
Margaret Rule
1 Cultural Heritage: The Archaeologist,
the Conservator and the Public – An Essential
Coalition 1
1.1 The Archaeologist 2
1.2 The Conservator 2
2 From Discovery to Display 3
2.1 Special Problems of Underwater Recovery 4
2.2 The Raising of the Mary Rose: A Case Study 4
2.3 Preservation of the Evidence:
A Multi-discipline Task 7
3 Conservation with a Purpose 10
4 Museums: The Past into the Future 11
References and Further Reading 12
Chapter 2 Methods in Conservation 13
A. Elena Charola and Robert J. Koestler
1 Introduction 13
2 Preliminary Examination 13
3 Analytical Methods 14
3.1 Interaction of Radiation with Matter 15
3.2 Interaction of Elemental Particles with Matter 19
3.3 Dating Methods 23
4 Diagnosis of Deterioration Processes 25
5 Conservation Treatments 25
5.1 Cleaning 26
5.2 Desalination 27
5.3 Consolidation 27
5.4 Disinfestation 28
6 Preventive Conservation 29
viii Contents
7 Conclusions 29
References and Further Reading 30
Chapter 3 Paper 32
Vincent Daniels
1 The Constituents of Paper 32
1.1 Fibres 32
1.2 Paper Size 35
2 The Directional Properties of Paper 36
3 How Paper Interacts with Water 37
4 Deterioration of Paper 39
4.1 Acid-Catalysed Hydrolysis of Cellulose 39
4.2 Oxidation of Cellulose 40
5 Deacidification 42
6 Bleaching and Washing of Paper to Remove
Discolouration 44
7 Foxing 47
8 Accelerated Ageing Tests 48
9 Safe Environments for Paper 49
10 Methods for Monitoring the Deterioration of Paper 50
10.1 Physical Measurements 50
10.2 Chemical Methods 52
11 Characterisation of Paper 54
12 Conclusions 55
References and Further Reading 55
Chapter 4 Textiles 56
Paul Garside and Paul Wyeth
1 The Variety of Textiles 56
2 Textile Materials 57
3 Case Study 1: Linen Fibres and the VictorySail 58
3.1 The Chemical Composition and Microstructure
of Linen 60
3.2 The Mechanical Performance of the
VictorySail 64
3.3 Degradation of Cellulosic Fibres 67
3.4 Acidity Measurements on the VictorySail 71
3.5 Conservation and Display of the Victory
Fore Topsail 72
4 Case Study 2: Silk Fibres and the Shackleton Ensign 73
4.1 The Chemical Composition and Microstructure
of Silk 74
Contents ix
4.2 Silk Processing for Use as a Textile Fibre 77
4.3 The Condition of the Shackleton Ensign 78
4.4 Assessing the Condition of Silk by
Microanalytical Techniques 79
4.5 Degradation of Silk Fibres 80
4.6 Conservation Treatment of the Shackleton
Ensign 83
5 Case Study 3: Wool Fibres and the Tree of Jesse
Tapestry 84
5.1 The Chemical Composition and
Microstructure of Wool 85
5.2 Wool as a Textile Fibre 87
5.3 Degradation of Wool 88
5.4 Assessing the Condition of Wool by
Microanalytical Techniques 90
5.5 Conservation and Treatment of the Tree
of Jesse Tapestry 90
6 Conclusions 90
Acknowledgements 91
References and Further Reading 91
Chapter 5 Leather 92
Roy Thomson
1 Introduction 92
2 The Nature and Properties of Leather 92
2.1 Criteria which Define Tannage 93
2.2 Collagen 96
2.3 Tanning Materials 98
3 The Manufacture of Leather 104
3.1 Vegetable Tanning Processes 105
3.2 Alum Tawing 109
3.3 Oil Tannage 109
3.4 Fur Dressing 109
4 The Deterioration of Leather 110
4.1 Physical Deterioration 110
4.2 Biological Deterioration 111
4.3 Chemical Deterioration 112
5 Conservation Techniques 115
5.1 Biological Deterioration 116
5.2 Chemical Deterioration 116
6 Conclusions 118
References and Further Reading 119