Pedro Alexandre Santos Leitão Caetano Alves 2015

281 Pages·2015·5.76 MB·English

by  Pedro Alves

UNIVERSIDADE
 DE
 LISBOA

FACULDADE
 DE
 CIÊNCIAS

DEPARTAMENTO
 DE
 QUÍMICA
 E
 BIOQUÍMICA

MOLECULAR
 ASPECTS
 OF
 THE
 CHEMICAL
 DRYING
 OF
 OIL
 PAINTS

FORMULATED
 IN
 THE
 PERIOD
 1890-­‐1940

Pedro
 Alexandre
 Santos
 Leitão
 Caetano
 Alves

DOUTORAMENTO
 EM
 QUÍMICA
 (QUÍMICA)

2015

UNIVERSIDADE
 DE
 LISBOA

FACULDADE
 DE
 CIÊNCIAS

DEPARTAMENTO
 DE
 QUÍMICA
 E
 BIOQUÍMICA

MOLECULAR
 ASPECTS
 OF
 THE
 CHEMICAL
 DRYING
 OF
 OIL
 PAINTS

FORMULATED
 IN
 THE
 PERIOD
 1890-­‐1940

Pedro
 Alexandre
 Santos
 Leitão
 Caetano
 Alves

Tese
 supervisionada
 pela
 Professora
 Doutora
 Maria
 Helena
 Ferreira

da
 Silva
 Florêncio
 e
 pelo
 Professor
 Doutor
 Jaap
 J.
 Boon

ESPECIALMENTE
 ELABORADA
 PARA
 OBTER
 O
 GRAU
 DE

 DOUTOR
 EM
 QUÍMICA
 (QUÍMICA)

2015

ACKNOWLEDGMENTS

This work would never been possible without the help, guidance, encouragement,
and belief of so many people that it’s hard not miss anyone who contributed in
some way to the completion of this thesis.
First I have to acknowledge my supervisors: Prof. Helena for accepting me as her
PhD student on a project she had no idea of, for mentoring me always and gave me
the liberty to learn from others in the conservation field, and for all the valuable
lessons in Life and Mass Spectrometry, as well as in Analytical sciences in general;
and to Prof Jaap Boon who I met personally in 2006 at the end of the De Mayerne
Programs and who believed that I could be trusted with a project that was not far
from what he had built up in the previous Molart program, for building a project
that is somehow a gap in our knowledge and giving me the best advice during all
these years now: “don’t try to reinvent the wheel” and “think critically”.
Also for putting me in contact with world experts in conservation science all over,
starting with Prof. Leslie Carlyle that was my “emeritus supervisor”, and was my
supervisor at Tate Britain Conservation Science, she taught me endless details of
conservation, and later when we both moved back to Lisbon, the endless hours of
fruitful discussion, conferences, paper reviewing, guidance and the “focus” word,
“you’ll have time for that at a Post-doc, Focus!” .
While at Tate with Leslie, I had the pleasure of being able to share the Lab and
critical thinking with Joyce Townsend (thank you for the samples on the Camden
town artists), Stephan Hackney and Bronwyn Ormsby (thank you ever since, and
the Py-GC/MS analysis) who were pretty much the high standard reference on
conservation science. Also to Jacob Thomas, for my research help, my first account
of PhD finishing at a close, while I was pressing Oils.
But back home I had so many times the assistance and advice from my GEMAB
group at FCUL, Prof. Carlos Borges (“we have a Book chapter!”), Prof. Filomena
Duarte (“keep it simple”) and Prof. Teresa Fernandez, as well as the younger
members that put up with me on a daily basis Pedro Vaz (FTIR doubts), now PhD
Paulo Madeira ( I could never thank you enough for all that you taught me on MS,
ion trap and FT-ICR, ESI or MALDI, thank you for being a friend “Daddy”) and
Rita, Tiago and Tânia, the “young team” for all the help the Lab, always believing in
my work, for being such good colleagues and great lunch times.
While in Amsterdam I have to thank Klass Jan van der Berg, for accepting me at
Netherlands Cultural Agency, and presenting me with a multidisciplinary and
collaborative place aiming at building knowledge across science and art, and giving
me access to the Technisches Mitteilungen fur Malerei whole archive. Also to the
“basement people” Francesca Izzo (we will publish soon on Rodchenko samples),
Beatriz and Alba Campo, for being such good people always with a smile.
In Lisbon I was also collaborating with José de Figueiredo Conservation and
Restoration Lab, this is where I fell in love with conservation science, back in 2001,
and cannot leave them out of these acknowledgments because they are the reason I
chose these field of work, where I developed my Masters and have always
supported me: Prof. António Candeias, Engª Isabel Ribeiro, Ana Mesquita e Carmo,
Lília Esteves, Zé Oliveira, Zé Carlos Frade, Sara Valadas, Milene Gil and all the
good people from the conservation departments.
I could not end this Thesis without my personal Friends, I’ll just say you know who
you are, and a special thank you. To Sandra for the final push till the End.
Aos meus Pais
INDEX

Acknowledgments

Chapter 1 Introduction 1

Chapter 2 Critical Review 13

Chapter 3 Raw Materials 110

Chapter 4 Analytical Techniques 161

Chapter 5 Discussion & Conclusions 218
1 A ’ O P –
RTIST S IL AINT
&
CONTROVERSY RESEARCH

ABSTRACT
This chapter reflects on the various perspectives of artist’s oil paint uses, with a focus on the research
on oil. Since the empirically based formulation introduced by artist’s to the colourmen, to the science
based developments in the raw materials, formulation, analysis and conservation science
particularly.

1.1 INTRODUCTION

There are extensive studies and general citations on the subject of oil paint studies,
and vegetable oils. The most widely used siccative oil is, by far, Linseed oil (Linum
usitatissimum) only to be followed by Poppy (Papaver somniferum) and walnut oils
(Junglans Regia). But it is thought that by the turn of the 19th to early 20th century
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there were changes introduced in artist’s oil paint formulation, mainly empirically,
by colourmen which would affect Art works ever since.
The main aspect we are here dealing with is the introduction of less siccative oils,
the semi-drying or even non-drying oils, in unknown quantities, which not only
prolongs the shelf life of tube oil paints but imparts new characteristics to the paint.
Other possible consequences of these less drying formulations have been studied, in
order to distinguish them from “normal” formulations, to understand the process
of dripping paints, as a direct consequence of less drying starting materials.

1.2 A TECHNICAL DESCRIPTION OF OIL PAINT

Historically artist’s oil Paint, as it has been used since early times, consists of a
Binder, or Vehicle, and the pigment. These were ground together in a slab of
Porfirus stone and collected with help of pallet knifes to be collected and stored in
pig’s bladders before the introduction of paint collapsible tubes.
The Pigments used are more or less described historically, ever since the first cave
drawings to modern pigments, industrial and synthetic, inorganic and organic.
As for the Binders less is known or at least less is agreed on unanimously, and this
is why we are here reflecting on this subject. Although it did not change as much as
the pigments, it changed from artist to artist and workshop to workshop
manufacturer and colourmen. In a simple way, the oil binding media consisted of
drying or siccative oil, named this way for the ability to form a dry film with time.
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