How to Preserve Photographic Artworks for the Future

162 Pages·2016·11.71 MB·English

How to Preserve Photographic
Artworks for the Future
Chemical and Physical Interactions and
Implications for Conservation Strategies
Reijers, Evert Bastiaan
Title: How to Preserve Photographic Artworks for the Future: Chemical and Physical
Interactions and Implications for Conservation Strategies
Utrecht, Utrecht University, Faculty of Science
Ph.D. thesis Utrecht University -with ref.- with summary in Dutch
ISBN 978-90-393-6657-8
The work described in this thesis was carried out in the Organic Chemistry & Catalysis group,
Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Utrecht,
The Netherlands
How to Preserve Photographic Artworks for the Future:
Chemical and Physical Interactions and Implications for
Conservation Strategies
Het Behoud van Fotografische Kunst voor de Toekomst:
Chemische en Fysische Interacties met Implicaties voor
Conserverings-strategieën
(met een samenvatting in het Nederlands)
Proefschrift
ter verkrijging van de graad van doctor aan de Universiteit Utrecht
op gezag van de rector magnificus, prof. dr. G.J. van der Zwaan,
ingevolge het besluit van het college voor promoties
in het openbaar te verdedigen op woensdag
11 januari 2017 des middags te 2.30 uur
door
Evert Bastiaan Reijers
geboren op 4 januari 1989 te Ede
Promotor: Prof. dr. L.W. Jenneskens
The work described in this Ph.D. thesis was financially supported by the NWO Science4Arts
programme.
Alles van waarde is weerloos
-De zeer oude zingt
Lucebert

Contents
Preface 9
Chapter 1 Introduction 15
Chapter 2 Materials in Photographic Art 27
Chapter 3 Free Fatty Acid Efflorescence on Contemporary 57
Photoworks and Canvas Paintings
Chapter 4 Factors Affecting the Formation and Extent of Free Fatty 79
Acid Efflorescence on Photoworks and Paintings
Chapter 5 Acid-Catalysed Degradation of Photodyes in Modern 97
Chromogenic Photographs
Chapter 6 Material Degradation during the Artificial Ageing of 123
Photographic Art
Concluding Remarks 139
Summary 143
Samenvatting 149
Dankwoord 155
Biography 159
Publications 161

Preface
Ever since prehistoric times, mankind has created art. Even our direct ancestor Homo Erectus
is believed to have made engravings, such as those recently discovered on a mollusc shell
in Java dated ca. 500,000 years ago.1 The oldest objects recognised specifically as works of
art are dated to a period around 35,000-15,000 years ago, and include carvings in stone and
animal bones2 as well as painted images such as the well-known cave paintings in Lascaux,
France.3 Even the earliest man thus placed value on aesthetic ideals beyond a direct and
practical purpose, and these ideals have only become more influential over time. As a wider
variety of materials and technologies became available, our ancestors had the opportunity
to create more elaborate artworks such as stone statues, paintings on walls and later canvas,
and objects made from wood, metals, glass, papyrus, parchment, paper, etc. The evolution
of art has accompanied that of mankind into modern times, where plastics, polymer-based
paints, synthetic dyes and photographs have become indispensable building blocks to many
contemporary artworks. Art and artistic expression have the ability to move and inspire us,
and can serve as a way to explore both one’s personal imagination and the world around us.
Additionally, artworks teach us important lessons about the era and societal circumstances of
their creation, and as such they are an essential record of human history and creativity.
Because of the unique cultural, historical and financial value of many objects, efforts to
preserve them have attracted interest for a long time. For example, the Vatican appointed
an official cleaner for the famous frescoes of the Sistine Chapel as early as 1543.4 In this
early period, conservation and restoration of artworks was very much left in the hands of
artists themselves, and restorations conducted during this time have sometimes resulted in
significant deterioration of these artworks. To better understand the degradation of artworks
and how to preserve them, chemists and physicists began to study degradation processes
from the 19th century onwards. For example, Michael Faraday conducted research into the
degradation of paintings at the National Gallery in London. He studied the effect of London’s
air, smoke-filled from extensive coal burning, on paintings, demonstrating that deterioration
of paintings increased during periods of fog or high humidity.5 However, due to technical
limitations, errors were frequently made in this kind of research, and it is partly for this reason
that large museums founded research institutes specifically to investigate the intricacies of art
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Preface
degradation and conservation. The Staatliche Museen zu Berlin in Germany was the first to
found such an institute in 1888, and many other museums and institutes followed suit. In this
way, scientific investigations became the primary basis for conservation science, and more
particularly, the conservation and restoration of valuable cultural heritage.
During the course of the 20th century, accepted practices in conservation and restoration of
museum art frequently changed. For example, in the 1920s it was common to restore or protect
ageing oil paintings by applying a layer of varnish. However, this varnish was found to turn
yellow and was able to interact with the underlying paint layer as well, therefore constituting
an additional problem rather than a solution.6 In light of such unexpected consequences, the
trend in the last decades has shifted towards monitoring and prevention of damage rather
than active conservation, so as to leave the artworks as authentic as possible.
In order to apply effective preservation or conservation treatments, it is imperative to
understand degradation processes as they occur in artworks during ageing. This involves
the physical and chemical study of various materials within these artworks, as well as their
interactions, surfaces and possible degradation products. The study of artworks in this
manner is associated with a unique combination of challenges. Because artworks often have
great historical, cultural as well as financial value, samples are either very small or cannot
be obtained at all. Microsamples require specialised equipment (e.g., µ-FTIR, µ-Raman) for
effective analysis, while other techniques may simply not be applicable. Because the number
of samples is limited as well, non-destructive techniques (e.g. reflectance IR) are preferred
over destructive techniques (e.g. SEM-EDX) which destroy the original microsample and will
therefore hamper further analysis.
Because of the inherent limitations and ethical considerations surrounding the collection of
(micro)samples from valuable artworks, non-invasive analysis is gaining attention.7 Handheld
devices are now available for non-invasive analysis techniques such as FTIR,8 Raman9 and
XRF,9,10 and dedicated set-ups are used to map entire artworks, identifying pigments, binders
and inorganic materials. These methods have the advantage of providing data on the entire
measured area (for example the surface of a painting) rather than relying on spot analysis,
thereby providing a more complete image of an artwork. Additionally, certain techniques,
notably XRF,11 can yield information about underlying layers, thus revealing initial sketches,
modifications, previous restoration treatments and even entire hidden artworks. In this
way, mapping techniques are of direct art historical interest besides their utility as tools in
restoration efforts. However, mapping techniques can be relatively time-consuming and
require rudimentary knowledge, at least, of the material under investigation. Mapping
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