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Reversibility and the right conservation treatment

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Reversibility has been thoroughly explored in conservation from all sorts of angles, and although it is agreed to be an unattainable concept, still nowadays remains a synonym of good practice. The article reviews this concept again seeking to unravel the aspects that actually define the essence of ethics and proficiency in heritage conservation. Reversibility is sized with regard to the chemical phenomenon, in relation to time and finally from the purely linguistic approach. The multiplicity of angles and the fact of being impossible in practical terms have trigged for the last years exhaustive ethical considerations about the nature of this profession. A few examples illustrate the contradictions involved in it. The types of treatments are then grouped by reversibility degrees. Relating the examples’ appropriateness to reversibility levels prompts that reversibility is no guarantee for good practice, neither irreversible treatments should be dismissed in the search for an ideal conservation. Appreciated conservation processes today are those with a proper equilibrium of stability, function and readability, executed in the most reversible way possible. This, and reporting accurately conservation interventions shall make our decisions acceptable for the generations to come.
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I
NTACH CONSERVATION INSTITUTES
CONSERVATION
INSIGHTS
2020
Lectures
Editing and Coordination
Dr. Padma M. Rohilla, Director, INTACH Conservation Institute, Delhi
Published by
Indian National Trust for Art and Cultural Heritage (INTACH)
INTACH Conservation Institutes (ICI)
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Email: intach@intach.org
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Copyright © INTACH 2021
ISBN: 978-81-954731-0-6
This publication includes articles contributed by speakers from the ‘Conservation Insights 2020’ lecture series organised by
INTACH Conservation Institutes (June-December 2020). Any views, conclusions and recommendations expressed in the
publication are those of the authors and do not necessarily reect the views of INTACH.
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic
or mechanical, including photocopying, microlming and recording, or by any information storage or retrieval system,
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Acknowledgements
INTACH Conservation Institutes would like to thank rst and foremost all the authors for contributing the
papers, reviewing and making this publication a reality. We are grateful to each one of you for sharing your
experience and knowledge.
We would like to take this opportunity to look back on the past year when everyone came together for
the ‘Conservation Insights 2020’ Lecture Series and thank all those who were involved and contributed.
We would like to thank Maj. Gen (Retd.), L.K. Gupta, AVSM, Chairman INTACH and Dr. (Mrs) Chuden
Tshering Misra, Member Secretary, INTACH for their continued support and encouragement that made the
online lectures and this publication possible.
We thank Mr. Nilabh Sinha, Principal Director, INTACH Conservation Institutes for his support through
the entire process.
We acknowledge the eorts of Dr. Padma M. Rohilla, Director, ICI Delhi in organising the lecture series
and putting together this publication.
iii
Contents
Foreword ..................................................................................................................................... v
Preface ........................................................................................................................................ vi
Natural Causes of Deterioration … NO … Error of Diagnosis
Gaël de Guichen .........................................................................................................................................................1
Biology and Cultural Heritage: Concepts, Denitions and Diagnostic Approach
Annalaura Casanova M., Flavia Bartoli ............................................................................................................... 6
Conservation of a Recent Conservation Based on Ethyl Silicate and Silica Sol
Albert Kieferle .......................................................................................................................................................... 18
A Procession of Banners: Improving the Preservation and Interpretation
of Flags and Banners in Devon and Cornwall, England, UK
Morwena Stephens, Helena Jaeschke ................................................................................................................ 26
Burn Out: Case Studies in Conserving Printed Textiles
Julia M Brennan, Kaitlyn Munro .......................................................................................................................... 42
Conservation Impacting Livelihoods
Pavithra Muddaya ................................................................................................................................................... 49
Materials & Weaves of Some Important Indian Textiles
B.B. Paul ..................................................................................................................................................................... 56
Indian Metallurgical Heritage and Archaeometallurgical Approaches
Sharada Srinivasan.................................................................................................................................................. 68
Conservation is About People
Dr Theresa Zammit Lupi ......................................................................................................................................... 82
The Value of Maintenance – The Important Role of Regular Maintenance
in the Conservation Process
Barbara Beckett ........................................................................................................................................................ 95
Injection Grouting for Delaminated Wall Paintings: Approach, Design, Challenges
Dr Chiara Pasian .......................................................................................................................................................114
On the Nature of and Managing Silver Tarnish
David Thickett, Kathryn Hallett .......................................................................................................................... 124
The Butrint Foundation’s Conservation Programme at Butrint, Albania: 1994-2020
Richard Hodges ....................................................................................................................................................... 135
iv
Understanding the Challenges of Historic Buildings in Ireland
David Humphreys, Nancy O’Keeffe ................................................................................................................... 146
A Heritage of Ruins: Southeast Asia’s Ancient Ruins and their Conservation
William Chapman ....................................................................................................................................................161
Digitizing the Materiality of Books. The (Potential) Role of the Conservator
Alberto Campagnolo ............................................................................................................................................. 172
Abydos Archive: Forgotten Cultural Heritage and Rescue Strategy
Ahmed Tarek, Wael Morad Ayman Damarany, Mohamed Abuelyazid & Nesma Mohamed ............... 189
Reversibility and the Right Conservation Treatment
Rita Udina ................................................................................................................................................................. 201
White Lead Discoloration and Conversion
Heather Hendry ....................................................................................................................................................... 211
Overlooked; Uncovering the Story of a Portrait with a Hidden History
Clare Finn .................................................................................................................................................................. 218
Painting Hiding Behind Painting: Rediscovery and Restoration of the Murals
in the Big Temple of Tanjavur, Tamil Nadu, India
Dr. Sethuraman Suresh ......................................................................................................................................... 226
Reectance Transformation Imaging (RTI)
Mohammed Ibrahim .............................................................................................................................................. 235
Introduction to the Conservation and Research Project on Pahari Drawings
from the Museum Volkenkunde, Leiden, The Netherlands
Amélie Couvrat Desvergnes ................................................................................................................................ 240
Earthen Architecture in the World – Valorization and Underestimation
Norma Barbacci ....................................................................................................................................................... 249
Stained Glass – Materials and Conservation
Steve Clare ............................................................................................................................................................... 260
The Preservation of Photograph Albums: Making Cross-Disciplinary
Decisions to Maximize Care
Georgia Southworth ............................................................................................................................................. 273
Reections on “Indian Ink”
Tammy Hong ............................................................................................................................................................ 284
Uncertainty in Conservation
Jonathan Ashley-Smith ......................................................................................................................................... 294
About INTACH Conservation Institutes (ICI) ............................................................................................ 304
About INTACH ...................................................................................................................................................... 306
v
Foreword
The INTACH Conservation Institutes works to advance conservation practices in art
and material heritage which includes objects, collections, architecture and sites. It serves
the eld of conservation through promoting best conservation practices, research, training,
capacity building, eld projects and the dissemination of its work and that of others,
in the eld. The aim is to create awareness of cultural heritage management issues and
dissemination of knowledge, that will benet professionals and organisations, working in
the eld.
The COVID-19 pandemic has resulted in a paradigm shift in the functioning of
organisations. INTACH too, is adapting and strengthening its online capacity building,
in heritage conservation. Many programmes and events were started to increase online
sharing of knowledge resources for the benet of the heritage conservation professional
community. The ‘Conservation Insights 2020’ lecture series was one such initiative. Its aim
was to promote networking of conservation professionals through an online platform.
The ‘Conservation Insights 2020’ lecture series, which was organised by INTACH
Conservation Institutes during June-December 2020, provided valuable insights, as the
name suggests, for conservation practice. It throws light on a variety of conservation
practices and is a valuable tool for learning in its own right. This publication includes
selected papers based on the lectures. The papers on various subjects related to cultural
heritage conservation, are specically intended for conservators, conservation scientists,
researchers and students in related elds. I thank all the authors who contributed to this
publication and shared their knowledge so willingly.
I hope this scholarly publication, and its dissemination, will help in knowledge creation
for the conservation community and for the curious layperson as well.
Dr. (Mrs) Chuden Tshering Misra
Member Secretary, INTACH
Foreword
The INTACH Conservation Institutes works to advance conservation practices in art
and material heritage which includes objects, collections, architecture and sites. It serves
the eld of conservation through promoting best conservation practices, research, training,
capacity building, eld projects and the dissemination of its work and that of others,
in the eld. The aim is to create awareness of cultural heritage management issues and
dissemination of knowledge, that will benet professionals and organisations, working in
the eld.
The COVID-19 pandemic has resulted in a paradigm shift in the functioning of
organisations. INTACH too, is adapting and strengthening its online capacity building,
in heritage conservation. Many programmes and events were started to increase online
sharing of knowledge resources for the benet of the heritage conservation professional
community. The ‘Conservation Insights 2020’ lecture series was one such initiative. Its aim
was to promote networking of conservation professionals through an online platform.
The ‘Conservation Insights 2020’ lecture series, which was organised by INTACH
Conservation Institutes during June-December 2020, provided valuable insights, as the
name suggests, for conservation practice. It throws light on a variety of conservation
practices and is a valuable tool for learning in its own right. This publication includes
selected papers based on the lectures. The papers on various subjects related to cultural
heritage conservation, are specically intended for conservators, conservation scientists,
researchers and students in related elds. I thank all the authors who contributed to this
publication and shared their knowledge so willingly.
I hope this scholarly publication, and its dissemination, will help in knowledge creation
for the conservation community and for the curious layperson as well.
Dr. (Mrs) Chuden Tshering Misra
Member Secretary, INTACH
vi
Preface
The COVID-19 pandemic disrupted our normal way of life and led to lockdowns of
institutions globally. During this period, INTACH also shifted to remote learning by
using online platforms and resources, in order to continue dissemination of knowledge.
The INTACH Conservation Institutes organised the online ‘Conservation Insights 2020’
lecture series from June to December 2020. There were in all seventy-eight lectures
given by experts from India and other countries including Italy, Germany, Spain, Malta,
Egypt, Netherlands, Ireland, Hawai’i, United Kingdom and the USA. The participants
included students from more than fty institutions, fellow colleagues, scholars and
researchers from around the world.
As a result of these lectures it was possible not only to link with individuals but many
institutions, specializing in the eld of heritage conservation. The lectures provided
invaluable opportunities for networking and exchanging expertise. The selected topics
varied from conservation of objects to understanding material, technology and research
projects developing in the eld of conservation. The success of this event was entirely due
to the speakers, who took time to prepare and deliver these online talks. We owe them a
debt of gratitude.
This publication, a compilation of selected lectures from the ‘Conservation Insights
2020’ series, represents another step towards sharing and dissemination of knowledge.
The lectures cover a wide range of issues related to philosophy of conservation, preventive
conservation, building conservation and the tools and techniques used in examination
and conservation of dierent materials. The subject matter is an invaluable contribution
to the eld and useful to practising professionals, researchers and students in the eld
of heritage management.
I take this opportunity to thank all the authors who contributed these papers, and for
sharing their knowledge and experience. I hope that this open access e-publication makes
for an interesting and informative resource and leads to better understanding of heritage
management.
Maj. Gen. (Retd.) L.K. Gupta, AVSM
Chairman, INTACH
201
19 October 2020
RITA UDINA is paper and book conservator based in
Barcelona (Spain) at her private conservation lab, where
she works for Archives, Museums, Libraries and private
collectors since 1999.
She teaches and organizes international conservation
courses at her studio as well as in other countries and
with other institutions. She does lectures, research and
short collaborations with paper conservators from other
countries as well (Restauratoren Nederland, Institut
National du Patrimoine, Paris; Cores from Belgium, Atelier
pour le Papier in Switzerland, Universidad de Granada…).
She enjoys sharing conservation issues in conferences,
papers, and on social media, particularly with her blog
(
https://ritaudina.com
) which has followers from all over
the world.
Rita Udina
Paper & Book Conservator,
Private Practice, Barcelona, Spain
Reversibility and the Right
Conservation Treatment
1 The Murray Pease Report: Code of Ethics for Art
Conservators. International Institute for Conservation of
Historic and Artistic Works – American Group (New York:
New York University, 1968), pp. 63.
Introduction
The idea to preserve the main features of
historical objects unaltered has been present
for all times. The term was rst used among
conservators in 19681 and increasingly
gathered momentum since then. It has been
thoroughly explored and although it is agreed
that is an unattainable goal, reversibility still
remains among the conservators community as
a paradigm of good practice. It is assumed that
any pro cient treatment is necessarily reversible,
and any irreversible one is at least the last
option of many to be considered. Nevertheless
reversibility in itself does not guarantee
bene cial results, neither irreversibility involves
a fatal loss of historical evidences.
202
‘CONSERVATION INSIGHTS 2020’ LECTURES
2 Reversibility: Does it exist? British Museum Occasional
Papers #135, 1999.
3 McGovern, Judith Reversible processes. PHYS20352
Thermal and Statistical Physics. University of Manchester.
Retrieved 2 November 2020. https://theory.physics.manchester.
ac.uk/~judith/stat_therm/node23.html (accessed May 2021).
4 Vincent Daniels (1999). Imperfect reversibility in paper
conservation. Reversibility: Does it exist? British Museum
Occasional Papers #135, 1999. pp. 48.
Fig. 1: Parchment manuscript detail from a 17th century
musical score bound in leather wooden boards. The old
sewn repair has succeeded along time to the point that
today does not lead to re-treatment upon most points of
view. Private collection
5 Vincent Daniels. “The reversibility of starch paste”,
Lining and backing (A. Phenix, ed.), UKIC, London, pp. 72-76.
Reversible… in which sense?
Which aspects of this concept actually de ne
the essence of good practice and which do not
(and should be avoided)?
1. Reversibility in conservation
In 1999 the British Museum published a book
entitled “Reversibility: Does it exist?”2. Quite
discouraging if the standards of the profession
are to be built upon a solid ground. The chapters’
adjectives plunge any such hopes deeper: Myth
and mis-use, ideal, illusion… or even a ghost!
Conservators from various disciplines
suggest it’s a concept to which actual practice
cannot really stick on in practical terms.
2. Reversibility and thermodynamics
Facing the fact from a purely scienti c angle
should help unravel all the hues derived
from reversibility as an ideal. The de nition
according to thermodynamics is “a process
that, after it has taken place, can be reversed
and, when reversed, returns the system and
its surroundings to their initial state”3, and
continues with the categorical a rmation that
“perfectly reversible processes are impossible”.
Are then conservators intending to make
interventions that go beyond the physical
limitations of thermodynamics? Because
however unrealistic that is, conservators
claim our treatments to be mostly reversible.
Vincent Daniels gives a fantastic example
on the common use of starch paste4, an
adhesive accepted as reversible in book and
paper conservation. Sticking to the chemical
approach, its solubility in dried state is found to
be less than 10%5, being therefore not possible
to remove completely. But in practical terms, it
comes easily apart after being soaked in water.
The visible residues can be scraped o , and
the remnants embedded among the bres are
invisible and unobtrusive to further treatments.
Starch paste would certainly not be
considered a suitable adhesive if reversibility
ought to be judged from a purely chemical
point of view. Thus reversibility is not really
a priority being followed, or not as long as
whatever is added on the artefact represents no
harm to it, either chemically or visually.
On the other hand, an example of a typical
not reversible repair which is valued not only as
a historical repair, but also for its e ciency in
the long term: the sewn repairs on parchment
( gure 1). Piercing a vellum folio is de nitely
203
Reversibility and the Right Conservation Treatment
6 Salvador Muñoz-Viñas. Contemporary Theory of
Conservation. Reviews in Conservation, number 3. 2002.
7 Umberto Baldini. Teoría de la restauración y unidad de
metodologia. Vol. 1 Ed. Nerea/Nardini. Traducción de
Marta Mozillo (Madrid, 1997).
8 Ashley-Smith, J. De nitions of Damage. Annual Meeting
of the Association of Art Historians, London, 1995. https://
cool.culturalheritage.org/byauth/ashley-smith/damage.html
(accessed May 2021).
9 Salvador Muñoz-Viñas (2002). Contemporary Theory of
Conservation. Reviews in Conservation, number 3. Pp. 25-
34. DOI: 10.4324/9780080476834. pp. 26.
not reversible, and nevertheless it is much more
e cient and innocuous than adhering a patch
or a tape: it does not cover the letters, does
not modify any chemical feature, nor lessens
the exibility of the parchment along the tear.
It can be re-repaired if ever the thread fails, it
ensures that no further damage shall take place
and enables a proper handling and reading at
all levels. If this type of repair was any better to
the current ones, or caused signi cant damage,
they would have been replaced more often.
3. Reverting in time: theoretical aspects
Reversibility can’t be beaten in physical terms,
and yet the search for it endeavours conservators
to re ect on their commitment towards heritage.
On this regard there’s an upmost holistic
approach developed by Muñoz-Viñas with the
Contemporary Theory of Conservation6.
Facing the temporal dimension of the term
revert, in its meaning of going to a previous
stage, requires de ning exactly which moment
in the object’s lifetime. Baldini sets three diverse
stages7: First the creation of the object, second
the lifetime and the conservation treatment as a
third stage. It seems reasonable to expect that
at least anything from the rst stage ought to
be kept as much unaltered as possible. But in
practical terms these stages do not delimitate a
real priority on what is to be preserved or not.
Taking pounce as an example, a nely
grinded powder used during the writing process
rst stage– to prevent inks from bleeding, and
which is often found in manuscript books. Such
powder is a soiling agent on a library and hinders
further consolidation treatments, subsequently
it is often removed. This historical evidence
can be kept aside in a bag for further research.
The impossibility of reverting cleaning processes
with an unavoidable loss of historical evidence
is somewhat compensated by preserving the
extracted remnants.
But strictly grouping in terms of time, the
same cannot be done with all evidence of the
manufacturing process. Iron-gall inks for
instance are also an indivisible component
of the manuscript. As well as rosin added on
paper sizing, which causes so much acidity,
or oils in impregnated tracing papers. Should
conservation treatments be restricted to the
damages occurred after the creation of the
object and avoid those arising from inherent
degradation of original components? The truth
is that preservation is inattentive to chemical
integrity whenever it compromises supports’
stability to a worrying extent. Deacidi cation is
the most paradigmatic non-reversible treatment
that is accepted as bene cial and necessary in
many cases.
At the second stage (lifetime of the artefact)
the eternal discussion about to which limit
patina should be preserved is not yet deciphered.
Because, where does patina end and where does
dirt begin? There is no physical way to slice
grime layers according to time, neither a logical
dating parameter to de ne these hypothetical
layers8.
When it comes to historical events what
does represent a meaningful episode of the
object worth maintaining, or not (and thus
removed?) is more ill-de ned. It is not related
to how old the episode is, neither to the scope
of the physical alteration it provokes, but to
subjective and immaterial reasons9.
204
‘CONSERVATION INSIGHTS 2020’ LECTURES
10 Erin Allen (2016). World War I: “Kim,” the Life
Saver, The Library of Congress Blog https://blogs.loc.gov/
loc/2016/10/world-war-1-kim-the-life-saver/ (accessed
May 2021).
11 Fletcher Durant. ICON Book and Paper Webinar Series
Conservation: Together at Home, #35: Conservation is not
neutral, and neither are we, https://youtu.be/bFKS12TYTEg
(accessed May 2021).
For instance, a book by Rudyard Kipling
literally stopped a bullet from killing a
legionnaire during World War. The grateful
survivor sent it later on to the author as
acknowledgement10. The Library of Congress
might never conceive repairing the munition
damage hollowing the folios, precisely because
the loss is actually the main value of the book,
and yet it occurred during the lifetime of that
copy and injured the book, hindering proper
reading for many folios.
As an opposite example, in 2012 a Russian
artist made an inscription on a Rothko painting
being exhibited in the Tate Modern (London).
The artist claimed it was adding value to the
Seagram mural, but Tate Modern deemed it
was defacing it, rather than improving it, so
the scribble was removed. A clear divergence
of opinions evidence the subjective nature of
what is a meaningful incident in the lifetime
of an item, as opposite to one that provides an
added value.
If no logical parameter de nes what should
be preserved from the past from what should
not, it is illusory assuming that there can
be de ned standards to set which from the
present conservation treatments need to be
more reversible for the future (since 100%
reversibility does not exist).
The third stage is unavoidably as subjective
as the previous two. Under what criteria a
certain amount of e orts is invested in
preserving some materials, whereas others
receive less attention? Quoting Fletcher
Durant “Conservation is not neutral, and
neither are we”11 .
Attempts to keep all evidences, no
matter what, are often not compatible with
conservation requirements. Old repairs are
frequently subject to such dilemmas.
Case #1: A manuscript plenty of repairs from
diverse periods
This 17th century manuscript is a very good
example. Most of the repairs are contemporary
to the writing of the manuscript and have
written text on it, while hiding the former
writing underneath ( gure 2). The patches had
been glued in a clumsy way, causing tension,
wrinkles and subsequent abrasion on a much
deteriorated paper.
Fig. 2: Before conservation. Green discontinuous line squares
the oldest adhered repairs. They caused severe tension on
the original manuscript, which already had older creases.
Orange line squares later pasted patches (probably
repairing the creases due to the former ones). The circle
enlarges a detail showing how accurately the writing
on the repairs matches the text underneath. Manuscript
from Regional Archive of Vallès Occidental (Terrassa,
Catalonia). Foto: Pep Soler.
The conservation treatment consisted
in keeping the glued repairs in place with a
main structural modi cation: replacement of
adhesion by a sewn attachment, which allowed
to see both inscriptions at the same time (repair
and original) and made it possible to atten
and consolidate the folio ( gure 3).
However, by doing this the third stage
(conservation) becomes quite another
205
Fig. 3: After conservation. Oldest adhered repairs (squared
in green) after detaching them from the manuscript and
attening the folio underneath. Repairs are now sewn but
loose, and can be ipped as a folio, allowing to read both
the patches’ text and the former writing below. More recent
repairs (squared in orange) were kept loose as well. The
circle enlarges a detail showing that the text on the patch
(top) and on the original (below) do not match anymore
after attening both papers. Manuscript from Regional
Archive of Vallès Occidental (Terrassa, Catalonia).
Photo: Paula Bueso
12 Barbara Appelbaum (1987). Criteria for Treatment:
Reversibility, Journal of the American Institute for
Conservation, 26:2, pp. 65-73,
DOI: 10.1179/019713687806027852.
protagonist in the manuscript’s lifetime.
Now the loose patches are not repairing
anymore, and the viewer needs an explanation
of the former stage to picture what the loose
patches mean in relation to the book, otherwise
it might be misleading. Ironically, allowing to
read simultaneously both texts (creation’s and
lifetime’s), as opposite to being able to read
only the second, might involve a lessening
of readability of the object understood as a
historical item. The message of the manuscript
transcending that one of a mere text provider
and speaking also about that old restoration
(intention, skills…).
4. Reversibility and linguistics
The word “reversible”12 fails in de ning the
boundaries of our profession, hence other terms
have often been used instead with the hope to
de ne a “good” conservation. Removability
or retreatability, for instance.
But ethics and good practice in conservation
are much too complex features to be
pigeonholed by one single term de ning
its appropriateness. “Reversibility”13, “retreat-
ability” and “removability” do not gather all
conservation treatments that are found eligible
in general terms, neither they exclude those
which are not.
These words cause conservators guilt
headaches more often than not, and make
them frustrated even when the outcome of
their e orts is accepted as successful. Or else
we lie to ourselves calling reversible treatments
those that are actually not.
Searching for the right conservation
treatment
Conservation processes keep some evidences
and disregard the rest, modifying the message
given by the object to some extent. It is expected
to be so, since damage and ageing are usually
the most purposely modi ed and appeased
features.
Decision making cannot be applied
systematically according to logical parameters,
it’s rather a subjective and mutable criteria:
no matter which stage of the artefact’s lifetime,
how old the historical interferences are, how
much harmful the damage is, and how reversible
the treatments are.
The appropriateness yearned for is a mixture
of concepts such as stability, functionality and
readability. Stability being the less abstract
and referred mostly to the preservation of the
13 Koenraad Van Balen, Ahmet Semih Ercan, Teresa
Patricio (1999). Compatibility and Retreatability versus
Reversibility: a Case Study at the Late Hellenistic
Nymphaeum of Sagalassos (Turkey). Use of and Need for
Preservation Standards in Architectural Conservation;
Vol. 1355; pp. 105-118. DOI: 10.1520/STP14185S.
Reversibility and the Right Conservation Treatment
206
‘CONSERVATION INSIGHTS 2020’ LECTURES
Fig. 4: Limp vellum binding with massive intended loss on
folios and cover (after 1980).
14 The lecture shows more examples of the same collection
not discussed in this paper to adjust to the desired extension.
Yet the cases explained have the main features to be debated.
Video and notes of the lecture accessible at: https://
ritaudina.com/en/portfolio/reversibility-in-book-and-paper-
conservation/ (accessed May 2021).
matter. Function is intimately connected to the
collection it belongs, which determines what
use that particular object is given (actual reading,
exhibiting, etc.). Reversibility is often sacri ced
for the sake of functionality: modi cations
that allow the object to be still in use are
deemed necessary (for instance, lining of iron-
gall ink manuscripts whose folios cannot be
handled safely otherwise). And readability is
connected to the abstract idea of meaning:
whatever is done to the object, it is expected to
deliver a particular (and selected!) information
at the end: the textual, its historical context,
the artistry…
Stability, functionality and readability
should be sought for in the most reversible
manner. The other way around: prioritizing
reversibility to reach the aforementioned
goals, is thermodynamically impossible and
arbitrary regarding the temporal dimension.
The outcome of a strict reversible conservation
would not necessarily t the actual goals in
heritage conservation.
Reversibility: Practical Examples
An empirical example of feasible reversibility
and appropriateness of conservation is shown
by some books belonging to the Library of the
Pharmacy Museum Alcon-Cusí14 (Masnou,
Catalonia). Thirty years after their restoration
the owners considered a re-treatment of the
books.
Case #1: Dioscorides by Andrea Matthioli,
1552
A printed book with limp vellum binding and
striking losses ( gure 4).
Former treatment (1980):
A conservation report in the book explains:
“Dated today all remnant of paper cancer
(purple stain) has been eliminated. Bear in mind
in case this paper disease arises again. October
27th, 1980. The conservator.”15
It is likely that the referred “cancer” was
a fungal degradation, and it is implied that
a surgical mutilation of any a ected parts
was executed as a conservation remedy. The
eradication was indeed deadly e ective, leaving
no evidence of purple stains at all. The report
does not provide further information, thereby
the outreach and nature of the so-called disease
cannot be weighted. In the mildest assumption
that the treatment did save what’s left of the
book from being completely lost, still it’s not
for us to know what it was like before 1980.
Present treatment (2010):
The in lling of such a massive paper loss
would be ine ective because of the sharp cuts,
15 Translated by the author: “En data d’avui ha estat
eliminat tot vestigi de càncer de paper (taca vinosa).
Tenir-ho present per si apareix novament aquesta malaltia
del paper. Masnou, 27 d’octubre del 1980. El conservador
(signat).”
207
which after all do not induce much further
deterioration in case of handling, so only the
binding was in lled, in order to recover the
protective function of the book cover. A custom
made foam board dovetails the shape of the
textblock so that there’s no distortion of the
binding during storage ( gure 5).
Case #2: Dioscorides Anazarbus, 1555
A printed book16 with red painted edges,
marbled endpapers and Spanish decorated
leather binding ( gure 6). There were some
pressure sensitive tapes and later patches on
top of them ( gure 7). The treatment report
of the former restoration was literally glued
on the back marbled pastedown, stating that
the book had been “Washed and restored by
E.P. Some folios are missing at the end of the
book. April, 198017.
Fig. 5: Before (left) and after the conservation treatment in
2010 (right). Bottom: Foam- board to t
16 Rita Udina (2015). Bibliopaths: The case of the lacquer
binding. Blog post https://wp.me/p4zghb-IE (accessed
May 2021). 17 Translated by the author: “Rentat i restaurat per E.P.
Falten algunes fulles en el nal del llibre. Abril, 1980”.
Reversibility and the Right Conservation Treatment
Fig. 6: Glossy leather and ine ective closing of the covers
due to the shrinkage of the leather caused by the varnish
Fig. 7: Discolouration of the painted edge (right, bottom),
tide-lines on the edges (left) due to bleach. Pressure-
sensitive tapes and later paper patches (centre)
208
‘CONSERVATION INSIGHTS 2020’ LECTURES
Former treatment (1980):
Besides no allusion to any treatment on
the binding was reported, the covers were
awkwardly glossy and remained slightly opened.
Apparently the book had been varnished at
some point, and the synthetic resin had slightly
shrank the leather, hindering the covers from
closing normally. The varnish was also blurring
the gilding on the spine ( gure 8).
Interesting to realize that the red painted
edges had been partially erased due to the
“washing” ( gure 7). This had consisted in
fact in locally wet cleaning the leaves’ edges
with bleach. Bleach not only erased the painted
edges, but also weakened the paper bres and
left numerous tide-lines.
The report did not mention the reason for any
of those treatments (unlike the previous example).
Present treatment (2010):
To the present point of view neither the
leather nor the folios needed consolidation
nor cleaning, therefore the treatment in 2010
consisted in reverting the negative e ects of
that restoration.
The varnish was removed with solvent
enough satisfactorily ( gure 8), both visually
and mechanically: The gilding was glowing
again, and the recovered hygroscopicity of the
leather allowed the covers to remain properly
closed, without tension.
It was deemed not necessary to recover the
visual appearance of the washed out painted
edge, that is to paint the whitened surface.
But the formerly bleached areas were locally
treated with water in order to remove the
possible bleach remnants on the paper and also
to reduce the tide-lines made at that time.
As for the paper patches and pressure-
sensitive tapes, they were all removed to
prevent further damage ( gure 9). The paper
strips were mechanically obtrusive to proper
handling and the tapes a source of oxidation
on the paper bres. It is well known that the
tape carrier and adhesive remnants can be
removed, but the oxidation derived from the
ageing of the synthetic resin is far from being
fully reverted.
To conclude, the varnishing is a very
much reversible treatment, and yet not really
appropriate: it shifts the appearance of the
leather and damages the binding. It is a reversible
but pointless and detrimental treatment to
nowadays standards, and it is found better to
Fig. 8: Split image. Top: Treatment of 1980 (varnishing). Bottom: treatment of 2010 (varnish removal)
Fig. 9: After 2010: strips and tapes removed, tears
consolidated again, tide-lines and bleach remnants reduced
209
be avoided. The same for paper patches, that
added malfunction and did not solve any issue
at all.
As for the “washing” (i.e. bleaching) and
the oxidation of the pressure sensitive tapes,
their consequences are not as reversible: the
painted edge is gone forever, and the chemical
change and discolouration of the paper cannot
be undone. Only part of the visual e ects
(the tide-lines), but not the weakening of the
paper. Washing and applying chemical changes,
are clearly not reversible treatments, and yet its
appropriateness could more likely be shared or
accepted as pertinent by other contemporary
restorers of that time, nding in bleaching a
good way to brighten old paper.
Table of reversibility in practical terms
The given examples substantiate that
reversibility is not a guarantee for praise-
worthiness of conservation treatments but
Reversibility and the Right Conservation Treatment
Reversibility Some examples of interventions
Altering physical 100% irreversible in any case. Slots, incisions, pierces, cuts, holes
integrity It’s the most categorically irreversible Fragmentation.
(seamless feature) type of treatment despite being usually Commonly involved in the reinforcement
accepted in relation to structural reinforcement. That’s because there’s clasps,
consolidation. For instance, assembling sewing folios, etc.
of wood boards or locks, in which the
minimal loss of support and bene ts
of the pursued consolidation
exceed the in icted decrease.
Removal Irreversible. Cleaning (wet, dry and surface).
Notwithstanding, whenever an Stain removal.
evidence of whatever removed parts Removal of corrupted materials (such as
are kept (patches, grime, varnishes…) rust, mould damaged or burnt matter…).
the loss might be less important in Paring down supports, trimming edges.
ethical terms, since it permits access to Old repairs and former treatments removal.
unattached samples, providing valuable ...
data of the previous stage.
Addition Less irreversible (in general). Inks  xation, varnishing.
Degree of reversibility varies from Consolidation (mending, lining, sizing,
0% to almost 100% depending on adhering…).
how the treatment is applied. Addition of materials (for instance, interleaving
In ethical terms, it is important to gauge of bu ered paper), which can alter the
how distinguishable the addition is neighbouring original supports.
from the original support. Especially for Inpainting / retouching (on original supports).
retouch, but also sizing and other ...
treatments, for an actual reversal of the
process shall not be a realistic option.
Modi cation Mostly irreversible (in practical terms). Chemical modi cation: Any reaction involving
Alterations can be grouped in chemical a chemical shift on the matter. Most wet
and physical, being the  rst much less treatments are (washing, variation of
reversible in general. conductivity, deacidi cation, chelating agents,
phytate…). Red-Ox treatments (any kind of
Structural changes though have implicit bleaching, pressure-sensitive tapes causing
historical and ethical consequences of oxidation…), lead white treatment, etc.
remarkable relevance, even if easier to Structural changes, for instance altering the
be reverted and without textual or order of folios on a book, or parts of it
visual implications. (concertinas), unsealing seals, but any
change implying a variation on this regard,
even if only relevant for structural means.
210
‘CONSERVATION INSIGHTS 2020’ LECTURES
–in case of regret– at least it allows a return
to the previous stage. However, the amount
of reversible processes that conservators are
likely to apply is quite small compared to
those that are not in practical terms.
A table groups them strictly according
to how reversible they are (not to what is
considered to be bene cial). In general terms,
they can all be classi ed in four: those which
alter physical integrity (the seamless feature of
an untouched support), removal, addition and
modi cation:
Conclusion
In conclusion, reversibility is no guarantee
for an eligible conservation treatment because
many reversible treatments are deemed not
pertinent to the present point of view. The actual
practice applies in fact more non-reversible
processes than reversible ones. Despite not
being the priority it is advisable to commit to the
highest degree within the existing alternatives,
because reversibility gives the chance of re-
treatment in case of regret.
Lack of reversibility has proven to be
very disappointing for forthcoming (and
current) generations, but only in case of major
disapproval. There shall be no such reprobation
if the conservation treatment ful ls the present
standards. Even when the intervention appears
old-fashioned to the future viewer, it shall be
well admitted as part of the object’s lifetime in
its historical context (see gure 1).
The appropriateness in the nowadays
conservation treatments ought to have a
right balance of stability, functionality and
readability of the artefact. The complexity of
this equilibrium lies in the fact that function
and meaning of an object might vary according
to the viewer’s background, the collection to
which the item belongs and other idiosyncratic
and mutable notions. However, searching for a
long lasting validity of the present decisions is
to be sought.
Be that as it may, facing such unreachable
goals should not discourage conservators from
assuming responsibility on the decision-making
and conservation practice.18 The profession is
entitled by the skills, the knowledge and the
experience. Our duty is to be most accountable
for every step and to report conservation
accurately, because future generations might
not share what has been done, but they shall
appreciate to know why, and more particularly
how and with what speci c products.
18 Jonathan Ashley-Smith (2016). Losing the edge: the
risk of a decline in practical conservation skills. Journal
of the Institute of Conservation, 39:2, pp. 119-132, DOI:
10.1080/19455224.2016.1210015.
306
About INTACH
The Indian National Trust for Art and Cultural Heritage (INTACH)
is India’s largest non-pro t membership-based organization dedicated
to conservation and preservation of India’s natural, cultural, living,
tangible, and intangible heritage. Its mission is to:
Sensitize the public about the pluralistic cultural legacy of India;
Instill a sense of social responsibility towards preserving our
common heritage;
Protect and conserve our living, built, and natural heritage by
undertaking necessary actions and measures;
Document unprotected buildings of archaeological, architectural,
historical and aesthetic signi cance; and cultural resources,
as this is the rst step towards formulating conservation plans;
Develop heritage policy and regulations, and make legal
interventions to protect our heritage when necessary;
Provide expertise in the eld of conservation, restoration and
preservation of speci c works of art; and encourage capacity
building by developing skills through training programmes;
Undertake emergency response measures during natural or man-
made disasters, and support local administration whenever heritage
is threatened;
Foster collaborations, Memoranda of Understanding (MoUs) and
partnerships with government and other national and international
agencies; and
Generate sponsorships for conservation and educational projects.
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