Estudos de Conservação e Restauro - SARC

Transcription

EDIÇÃO | PUBLISHER
REVISORES CONVIDADOS PARA ESTE NÚMERO |
Centro de Investigação em Ciência e Tecnologia
INVITED REVIWERS
das Artes (CITAR) - Universidade Católica
Agnes-le-Gac
Portuguesa | Research Center for Science and
Carolina Barata
Technology of the Arts - Portuguese Catholic
João Coroado
University
Pedro Flor
Mercês Lorena
DIRECÇÃO | EDITOR
Rui Bordalo
Eduarda Vieira
Teresa Alexandra Ferreira
CONSELHO DE REDACÇÃO | EDITORIAL BOARD
ASSISTENTE DE EDIÇÃO | LAYOUT
José Carlos Frade
Carlos Gonçalves
Salomé Carvalho
ISSN
COMITÉ CIENTÍFICO | SCIENTIFIC COMMITTEE
1647-2098
Ana Calvo
A. Elena Charola
PERIODICIDADE | FREQUENCY
Amélia Dionísio
Anual | Anual
António Candeias
António João Cruz
DATA | YEAR
Cláudia Rodrigues Carvalho
2015
Cristina Dias
Edson Motta Júnior
CAPA | COVER LAYOUT
Griselda Pinheiro Kluppel
Ângela Monteiro
Irina Sandu
Isabel Medina-González
IMAGEM DA CAPA | COVER PHOTOGRAPH
João Manuel Mimoso
The behaviour of Schlagmetal applied on different
Joaquín Barrio
types of gilding sizes, pp.72-84
Jonathan Ashley Smith
EDIÇÃO, PROPRIEDADE E REDACÇÃO | PUBLISHER
José Aguiar
Leslie Carlyle
AND EDITORIAL OFFICE
Margarita San Andrés Moya
Centro de Investigação em Ciência e Tecnologia
Maria del Carmen Bellido-Márquez
das Artes (CITAR) - Universidade Católica
Maria Dolores de Lacanal
Portuguesa - Centro Regional do Porto
Maria João Baptista Neto
Rua Diogo Botelho 1327
Maria Regina Emery Quites
4169-005 Porto, Portugal
Mercês Lorena
CITARECR@GMAIL.COM
Milene Gil Casal
Nieves Valentín
As opiniões publicadas nesta revista são da
Patricia Moreira da Costa
exclusiva responsabilidade dos seus autores e
Pilar Roig
não reflectem a opinião da Direcção, do Conselho
Raquel Carreras
de Redacção e do Comité Cientifico. | Authors
Rocio Bruquetas
are solely responsable for all views and opinions
Vasco Peixoto de Freitas
contained in ECR, which do not necessaraly
represent those of the Editor, Editorial Board or
SECRETÁRIA DE EDIÇÃO | ASSISTANT EDITOR
of the Scientific Committee.
Ângela Monteiro
Avaliação anónima por pares/
Anonymous peer review
| nº 7 - Special Issue
2
Índice |Index
Editorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Artigos | Articles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
GILT-TELLER: A NOVEL MULTIMEDIA TOOL FOR OUTREACH IN
CONSERVATION AND HERITAGE SCIENCE
Irina Crina Anca Sandu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
MATERIAL CHARACTERIZATION OF GILDING AND PAINTING TECHNIQUES
OF A POST-BYZANTINE ICON
Maria Oliveira | M. Teresa Crespo | Sónia Costa | Cristina Barrocas Dias | Ana
Manhita | Ana Cardoso | Luís Dias | António Candeias . . . . . . . . . . . . . . . . . . . . . . . . 22
GOD IS IN THE DETAIL. GOLD, SILVER AND POLYCHROMY
Tiago Dias | Michèle Portela | M. José Oliveira | Elsa Murta | Cristina Barrocas
Dias | Vítor Serrão. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
A COMPARATIVE MULTI-ANALYTICAL STUDY OF THE POLYCHROMY AND
GILDING IN TWO BAROQUE ALTARPIECES OF EVORA, PORTUGAL
Celso Mangucci | Irina Crina Anca Sandu | Ana Manhita | Ana Margarida
Cardoso | Luís Dias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
THE BEHAVIOUR OF SCHLAGMETAL APPLIED ON DIFFERENT TYPES OF
GILDING SIZES
Ana-Maria Budu | Ioana Hutanu | Viorica Vasilache | Ion Sandu . . . . . . . . . . . . . . . 72
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Editorial
Entre os dias 25 e 27 de Maio de 2015 realizou-se na Universidade de Évora a Conferência Internacional sobre Materiais e Técnicas de Douramento na Arte Europeia-GILT-EnART 2105, evento que teve
o patrocínio da Fundação para a Ciência e Tecnologia de Portugal (FCT-MCTES). Esta Conferência
constituiu o resultado final do projecto Gilt-Teller (www.uevora.gilt-teller.pt), e simultaneamente, um
modelo de interacção e de partilha de conhecimento entre os especialistas da comunidade científica
do Património Cultural.
A revista ECR- Estudos de Conservação e Restauro, dando continuidade ao seu propósito de disseminar
o conhecimento científico produzido na área da conservação e restauro numa perspectiva multidisciplinar, apoiou o evento convertendo o seu número 7 numa edição especial que integra algumas das
mais relevantes comunicações seleccionadas.
A presente edição especial integra 5 artigos resultantes de comunicações orais e posters apresentados
ao longo das 6 sessões da Conferência:
1)Fontes Históricas e Técnicas para o estudo dos materiais e técnicas de douramento;
2)Estudos de avaliação de estados de conservação e de conservação e restauro de objectos dourados;
3)Estudos Analíticos multidisciplinares e multiescala aplicadas a objectos dourados;
4)Das fontes históricas à reprodução em laboratório das receitas de douramento;
5)Materiais e técnicas de douramento entre a Europa e outros países ultramarinos;
6)Estratégias de difusão e de disseminação.
Assim, as temáticas relacionadas com os estudos históricos (Secção 1), as análises científicas aplicadas a altares barrocos nacionais (Secção3), o estudo da policromia de uma escultura e de um ícone
pós-bizantino portugueses (Secções 3 e 5) estão plasmados em três artigos da autoria de Mangucci
et al, Dias e Oliveira et al. O artigo de Ana-Maria Budu e seus co-autores apresenta um estudo sobre
o comportamento de um substituto da folha de ouro (schlagmetal) aplicado em intervenções de
conservação e restauro de ícones romenos (Secções 2+4+5).
Por fim, o artigo de Irina Sandu (Secção 6) apresenta-nos uma ferramenta multimédia desenvolvida
no âmbito do projecto GILT-Teller para a divulgação da Ciência da Conservação.
O conjunto destes artigos e tópicos neles incluídos confirmam a tendência actual no sentido de
uma colaboração multinacional e multidisciplinar no domínio do Património Cultural, confirmando a
relevância das abordagens interdisciplinares no tocante ao estudo, conservação e restauro adequados
dos objectos culturais dourados e policromados. Esta visão holística interdisciplinar é, igualmente, um
requisito fundamental para a promoção deste tipo de bens culturais.
Irina Sandu
Organizadora e Presidente da Conferência GILT-EnART 2015
Eduarda Vieira
Directora da Revista ECR-Estudos de Conservação e Restauro
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Foreword
Between 25th and 27th of May 2015 the first International Conference on Gilding Materials and Techniques in European Art – GILT-EnArt2015, was held at the University of Évora, being organized with
the support of the Portuguese Foundation for Science and Technology (FCT-MCTES). This conference
was an output from the Gilt-Teller project (www.uevora.gilt-teller.pt) and represented a model of
interaction and knowledge sharing among specialists of the Cultural Heritage community.
The ECR- Studies in Conservation and Restoration Journal, following up its purpose of disseminating
the scientific knowledge produced in the conservation and restoration area in a multidisciplinary
perspective, supported the Conference dedicating its number 7 to a Special Issue that includes some
of the most relevant selected papers.
As a result, the present Special Issue proposes 5 papers delivered as oral or poster communications
during the 6 sessions of the conference:
1) Historical and technical sources on gilding materials and techniques;
2) Conservation state assessment and conservation-restoration studies on gilded artifacts;
3) Multiscale and multidisciplinary analytical studies on gilded artifacts;
4) From the historical sources to the reproduction of gilding recipes in the laboratory;
5) Gilding materials and techniques between Europe and Overseas countries;
6) Outreach and dissemination strategies.
Thus, historical findings (Session 1) and the scientific analyses performed on baroque altarpieces
(Session 3), a polychrome sculpture (Session 3) and one post-Byzantine icon (Sessions 3+5) from
Portugal are presented in 3 papers (Mangucci et al, Dias et al and Oliveira et al). One paper deals
with the conservation state assessment and evaluation of interventions using substitutes for gold leaf
(shlagmetal) in Romanian icons (Budu et al, Sessions 2+4+5). Finally the last session (Session 6) is
represented by a paper dealing with the multimedia tool accomplished during the GILT-Teller project
for Outreach in Conservation and Heritage Science (Sandu ICA).
These papers and the topics they cover illustrate the trend of multidisciplinary and multinational
cooperation in the cultural heritage field. They show how important is to gather information from different scientific areas when studying gilding/polychrome materials and techniques and discussing the
options and solutions for their proper conservation and restoration. This holistic and interdisciplinary
approach is a basic feature for the effort of preservation and promotion of the precious gilded heritage.
Irina Sandu
Organizer and Chair of the GILT-EnART 2015 Conference
Eduarda Vieira
ECR-Studies in Conservation and Restoration editor
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Artigos |Articles
6
GILT-TELLER: A NOVEL MULTIMEDIA
TOOL FOR OUTREACH IN CONSERVATION
AND HERITAGE SCIENCE
Irina Crina Anca Sandu1
1
Hercules Laboratory, Evora University, Portugal
Abstract
The paper focuses on an innovative bilingual multimedia tool designed within the research
project funded by the Portuguese Foundation for Science and Technology (FCT) – Gilt-Teller,
an interdisciplinary multiscale study of gilding techniques and materials in Portugal, 15001800. The tool was designed with the help of the company Take the Wind Lda. (Coimbra)
and is based on an online platform (www.gilt-teller.pt). It has different components, from
documents of general description of the project, its team and outcomes in terms of publications and conference presentation or workshop organization to the historical background
of the project and short characterization of the main stylistic époques considered under
study. The three innovative components are: the bilingual glossary on gilding materials and
techniques (http://www.gilt-teller.pt/index.php/glossary/index); a movie with the data on
laboratory documented reconstructions of gilded composites based on Portuguese recipes
(http://www.gilt-teller.pt/index.php/site/historicalReconstructions) and 11 case studies
with gilded decoration from the European heritage (http://www.gilt-teller.pt/index.php/
site/additionalMaterials)
For the first time in Portugal an open access bilingual database including the most representative altarpieces and polychrome sculptures studied within the project was made available
to larger and specialized public. For the first time this multimedia tool will bring together
knowledge from three different scientific areas, all related with the topic of the project: Art
History (with a component of Technical Art History), Conservation and Heritage Science.
Keywords
Multimedia, tool, gilding materials and techniques, Portuguese woodcarved decoration.
Gilt-Teller:uma Nova Ferramenta Multimédia Ao Serviço Da Divulgação
Da Ciência Da Conservação
Resumo
O presente trabalho apresenta uma ferramenta multimédia inovadora desenvolvida no
âmbito do projeto de investigação financiado pela Fundação para a Ciência e Tecnologia
(FCT): “GILT-Teller, um estudo interdisciplinar multiescala das técnicas e dos materiais de
douramento em Portugal, 1500-1800”.
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GILT-TELLER: A NOVEL MULTIMEDIA TOOL FOR OUTREACH IN CONSERVATION AND HERITAGE SCIENCE
Irina Crina Anca Sandu
A ferramenta desenvolvida com a contribuição da companhia Take the Wind Lda. (Coimbra) é baseada numa plataforma online (www.gilt-teller.pt) e contém vários componentes
entre quais se destaca a base de dados constituída por vários casos de estudo do território
nacional abrangendo diferentes estilos de talha dourada no período 1500 e 1800. Além
dessa base de dados a plataforma online inclui também outras três componentes inovadoras,
nomeadamente um glossário bilingue sobre materiais e técnicas de douramento (http://
www.gilt-teller.pt/index.php/glossary/index); um filme sobre as reconstruções históricas de
provetas douradas realizadas em laboratório com base em receitas portuguesas (http://
www.gilt-teller.pt/index.php/site/historicalReconstructions) e 11 casos de estudo de objectos
com decoração dourada do património cultural europeu (http://www.gilt-teller.pt/index.
php/site/additionalMaterials).
Pela primeira vez na história do património religioso português, esta ferramenta reúne o
conhecimento de três áreas científicas diferentes: História da Arte (com uma componente
de Historia da Arte Técnica) Conservação e Restauro de Talha Dourada e Ciências da Conservação e do Património Cultural.
Palavras‑chave
Ferramenta multimédia, materiais e técnicas de douramento, decoração em talha dourada
portuguesa.
GILT-TELLER: UNA NUEVA HERRAMIENTA PARA LA DIVULGACIÓN DE LA
CIENCIA DE LA CONSERVACIÓN
Resumen
Este artículo presenta una innovadora herramienta multimedia desarrollada dentro del
proyecto de investigación financiado por la Fundación para la Ciencia y la Tecnología (FCT):
“GILT -Teller un estudio interdisciplinario multiescala de las técnicas y materiales de dorado
en Portugal, 1500-1800” .
La herramienta desarrollada con la colaboración de la empresa Take the Wind Ltd. (Coimbra) se basa en una plataforma en línea (www.gilt-teller.pt) y contiene varios componentes
entre los que destaca una base de datos con varios estudios de casos del territorio nacional
cubriendo diferentes estilos de dorado en el período de 1500 hasta 1800. Además de esta
base de datos, la plataforma en línea también incluye otros tres componentes innovadores,
a saber, un glosario bilingüe de materiales y técnicas de dorado (http://www.gilt-teller.pt/
index.php / glosario / index); una película sobre las reconstrucciones históoricas de las
muestras realiza en el laboratorio basadas en recetas portuguesas (http://www.gilt-teller.
pt/index.php/site/historicalReconstructions) y 11 estudios de caso de objetos con decoración
dorada del patrimonio cultural europeo
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Por primera vez en la historia del patrimonio religioso portugués una herramienta combina
el conocimiento de tres diferentes áreas científicas: Historia del Arte (con un componente
de la historia del arte Técnico) Conservación y Restauración de oro Talha y Ciencias y la
conservación del patrimonio cultural.
Palabras clave
Herramienta multimedia, materiales y técnicas de dorado, decoración en talla portuguesa.
Introduction
The Gilt-Teller project (www.gilt-teller.pt) is a research project funded by FCT (Portuguese
Foundation for Science and Technology) dealing with historical, technical and analytical
study of gilding materials and techniques [1] in the gilded woodcarved decoration (“talha
dourada”) from Portuguese churches during 3 centuries (ca. 1500-1800).
“Talha dourada” is a singular type of gilded decoration on wooden support developed in
Iberian Peninsula and that in Portugal knew its outermost expresson during the Baroque
époque. This decorative phenomenon has been adopted and spread together with other
artistic techniques such as “azulejos”, in the form of a complete work of art and a national
mark for this country, expressing also the religious faith and a catechetical message [2-5].
Although subjected to intensive historical research, “talha dourada” decorations all over the
Portuguese territory were not systematically investigated from the material and technical
points of view and many churches and museums house today altarpieces, retables and other
wooden and gilded decorations, never studied. Thus, the Gilt-Teller research was meant to
fill this lacuna and launch a pilot-project on the territory [6]. Due to the limited amount of
time versus the huge amount of altarpieces and other woodcarving typologies of artefacts
(ecclesiastic furniture, sculptures etc.) spread allover Portugal, the project focused on some
geographic areas (Algarve, Aveiro, Coimbra, Evora, Guarda, Lisbon and surroundings, Miranda
de Douro, Portalegre, Santarém, Viseu and Funchal in Madeira island) and on three typologies of objects: main, lateral and collateral altarpieces from churches and chapels, gilded
choir stalls and polychrome sculptures with gilded decoration. The main criteria considered
for selecting the altarpieces and sculptures were: historical and artistic values, pointing out
the esthetical and cultural relevance of the case studies in close relationship with: presence
of historical documentation (work contracts and other documents from the same époque),
presence or not (better if not) of past interventions, their conservation state, prediction of
future treatments (sampling campaign organized before the start of restoration intervention
or during it).
Within this study the fifth task was focused on the design of an innovative multimedia
bilingual (Portuguese/English) tool in the form of a website supporting a database of open
access. This task involved several members of the working group (the PI being responsible
and coordinator of the design and compilation of the components of the database) and the
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consultants from abroad and Portugal (http://www.gilt-teller.pt/static/pdf/2_instituicoes.pdf).
Their work and interaction provide also a model for interdisciplinarity and multidisciplinarity
in the field of conservation and heritage science.
The website was created in the form of a virtual trip into gilding materials and techniques,
illustrating the historical, artistic and scientific background of the studies performed during
the project (covering 5 research tasks and one of dissemination and Outreach activity).
Conceived as an interactive map of Portugal (Fig. 1) on which several points were marked
to indicate the location of important gilded objects studied in the project, the tool shows the
complexity of “talha dourada” from three perspectives: the historical and stylistic one (the
classification of the altarpieces being done based on the historical-stylistic attribution), the
conservation one (each object taken into study was provided with technical sheets resuming
its conservation state and other technical data), and the scientific perspective from various
scales of characterization (from Macro to Nano) [7-9].
Figure 1 – English version Homepage of the website and online database with a case-study
(Mannerist style) pointed on the map.
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Functions of the tool
The Gilt-Teller tool has several functions: database structure, comprising various typologies
of documents (texts, static images, graphs, movies etc.); easy and friendly-accessible,
available online and also on a magnetic support (DVD) or pendrive in the form of a movie
explaining how to access and search the information; experimental and virtual instrument,
allowing real-time multi-level interaction with the fruiters/public; capability to be transferred
and integrated in an alternative, unconventional system of training (e-learning); capability
to be applied and up-dated to/with similar case studies or research topics (technological
transfer), allowing also comparative studies; capability to apply it for monitoring the preservation state of the studied artifacts (gilded surfaces and composites) and to evaluate in
time the effects of restoration treatments; capability to offer the basis for the creation of
an international network/forum for research and knowledge/know-how transfer.
Applications of the tool
The applications of the GILT-Teller are various and incorporate an Outreach dimension that
conservation field can adopt for better dissemination of its activities, covering a wide range
of end-users from the general public to the students in conservation of ecclesiastic heritage.
The tool was designed as a milestone from the research activities of the project but at the
same time its functions makes it available as an innovative instrument for didactic activities in e-learning systems in the fields of Art History, Conservation and Heritage Science.
The database stored on the online platform represent also a mean to draw the attention
of the wide public on these particular typologies of heritage (comprising their material and
techniques) and their problematic (from the lack of documents testifying the authorship or
posterior interventions to a precarious conservation state and lack of strategy in monitoring
and preserving this heritage). The database content, although limited for now to several
case-studies, can offer the background for further comparative studies on gilding materials
and techniques in Europe (and not only, if we consider that Portuguese Baroque Art was
spread on five continents during the Portuguese expansion) and can be subject to updgrading
the information with other case-studies from the Portuguese territory, for the moment not
included in the study. As the database contains sheets with reports on the conservation state
of the investigated altarpieces/sculptures, it can also be useful in monitoring campaings of
their state over time.
Components of the online tool
Based on the collaboration with Take the Wind Lda. from Coimbra, a layout of the online
bilingual (Portuguese and English) tool and database was built up [9]. Texts and images were
provided by the involved members of the project in order to create a series of pdf documents
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that describe the project, its objectives, participants, milestones and the typologies (styles
of “talha” or sculptures) of studied artworks.
The structure of the tool (Figure 1, layout of the Home page and example of the case study)
is based on a Bottom Menu (Fig. 2), where general and specific information on the activities
and components of the project are provided and an Upper Menu with types/styles of “talha
dourada” (in fact this menu is the database of case studies designed as a map of Portugal).
Figure 2 – Bottom menu of the website – examples of pdf documents
accessed for different sections.
The first column of the Bottom Menu contains General information on the project, its members and participating Institutions, Publications and Dissemination actions (participation to
conferences, workshops etc.) and the Historical background of the project.
The second column contains more technical data, on Recipes and treatises on gilding,
Historical reconstructions of gilded composites, Gilding materials, Gilding techniques and
Additional Materials. The HISTORICAL RECONSTRUCTIONS (task 4) of four recipes of
gilding (two of watergilding and two of mordant) from XVIIth (Filipe Nunes) and XVIIIth
(José Lopes Baptista de Almada) century treatises [10] were video and photo-recorded
12
and the final results were uploaded on the website as a movie with 10 chapters (Fig. 3). In
the ADDITIONAL MATERIALS section, collaborations with specialists from Czech Republic,
Italy, Germany, Romania, Portugal and Spain, led to the compilation of 11 technical sheets
with analytical data on gilding materials and techniques from samples taken from foreign
artefacts (icons, sculptures, frames and panel paintings) (Fig. 4).
Figure 3 – Different frames from the Historical reconstructions movie.
The third column contains the GLOSSARY and a link to the website of the final conference
of the project, GILT-EnArt2015, held between 25th and 27th of May 2015 in Evora, Portugal.
The Glossary has a complex and innovative content, illustrating through texts and static/
dynamic images the terminology related with all three components of the project: History,
Conservation and Science (Fig. 5). The Glossary was built up in 7 chapters: first one from
Art History on altarpiece structure and decorative elements according each historical and
artistic style, second and third chapters describing techniques and materials for gilding,
fourth and fifth chapters focusing on terminology from Conservation and Restoration field
on gilded artefacts and the sixth and seventh chapters dedicated to scientific analytical
techniques used in the project and basic terms from the scientific field.
13
Figure 4 – Additional materials menu.
Figure 5 – The bilingual interdisciplinary glossary components.
14
The fourth column includes the short description, from a historical perspectives, of the main
styles of talha (Renascentist, Mannerist, Baroque, Rococó, Neoclassical) and the Polychrome
sculpture typology of objects.
The Database (Fig. 6) was organized in technical sheets structuring the main information
obtained from the research activities undertaken during the first three tasks of the project.
At the present the database include 1 case study (choir stall) for Renascentist, 8 Mannerist,
18 National Baroque (including 1 Proto-Baroque), 9 Joanine Baroque (1 is choir stall), 3
Rococó and 1 Neoclassical altarpieces and 2 polychrome and gilded Sculptures [8, 11-15].
The components of a case study will be illustrated using the Main Altarpiece of the Church
of Sorrow in Lisbon [15] (Figures 7-10). The first document contains GENERAL data about
the altarpiece including a general view on it (image). The following data sheets are organized according the main categories of information provided by the analytical methodology
of study: SAMPLES, LAYERS of gilded structures from each sample, MATERIALS of gilding,
TECHNIQUES of gilding. This part can be considered a first level of access, for general public,
as contains texts and images that everyone can basically read and understand.
The second level is recommended for specialists and students in conservation field as it
contains more detailed data about the CONSERVATION STATE of the objects, the samples
and their characterization using several conventional and unconventional ANALYTICAL
TECHNIQUES. Each sample is identified using an acronym derived from the acronym of the
object/case-study (e.g. for our case-study: PT-AM-NSPLx = Portugal - Altar Mor - Nossa
Senhora da Pena Lisboa).
Traditional analytical techniques (optical microscopy, spectroscopy, X-ray difractometry)
together with innovative tools, such as time-of-flight mass spectrometry (MALDI-TOF-MS),
imaging microFTIR, immunological assays (ELISA), fluorescent dyes (Sypro Ruby), atomic
force microscopy (AFM) and micro-computerized tomography (µ-CT) were used to study
the gilding materials and techniques of more than 45 altarpieces and sculptures all over
Portugal. The summary of the scientific results obtained during the analytical campaign were
elaborated within the sections of the database, from the more general to the more specialized
such as: Objects and analytical techniques (simply a table with analyses perfomed for each
sample of a studied object, Figure 9) and Analytical Techniques (here, according the list of
techniques provided in the previous table/section, a description of the operational conditions
of each instrument and of the results obtained for the analyzed sample is given, Figure 10).
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Figure 6 – Database and styles description of “talha dourada” in the Bottom menu.
Figure 7 – The general data sheet of the altarpiece (English version) with the Menu (upper right
side) showing the main sections for this case-study and the localization on the map (database).
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Figure 8 – The data sheet with the description of the conservation state of the altarpiece
(English version).
Figure 9 – Data sheet (table) with analytical techniques by samples (English version).
17
Figure 10 – Examples of description of analytical techniques for one sample
(OM and SEM-EDS for sample 1, English version).
Conclusions
The structure and the content of the bilingual Gilt-teller tool described here, show the
potential and functions of this online and open access platform and database for research,
didatic and dissemination purposes. The Gilt-teller multimedia content facilitates the easy
acess to the available information to general and specialized public.
The innovation that the tool and database bring into the field of Cultural Heritage research
is the cross-bridging of three components of the project: History, Conservation and Science
both at the level of how the information is structured and presented (using technical sheet
with data on the history of the studied objects, the gilding materials and techniques, their
conservation state etc. but also mujltimedia components such as the videos on Historical
reconstructions and the Introduction to the Glossary) and as far as the terminology is
concerned (organized in the form of a bilingual multimedia Glossary).
Acknowledgements
This work has been supported by Fundação para a Ciência e a Tecnologia through grant no.
PTDC/EAT-EAT/116700/2010. Authors are also grateful for the support of IMAGOS – Inovative Methodologies in Archaeology, Archaeometry and Geophysics – Optimizing Strategies X
APOLLO - Archaeological and Physical On-site Laboratory – Lifting Outputs, n. ALENT-070224-FEDER-001760, funded by INALENTEJO programme through FEDER Project.
The involvement of the following persons: Elsa Murta, Silvia Ferreira, Pedro Flor, Lia Jorge,
Rita Veiga, Francesca Paba, Patricia Monteiro, Manuel Costa Pereira, Antonio João Cruz,
18
Nuno Leal, Tito Busani, Mariella Lobefaro, Stepanka Hrdlickova Kuckova, Mark Richter, Carlos
Nodal, Agnès Le Gac, Ion Sandu, Miguel Barros, is also gratefully acknowledged.
References
[1] SANDU Irina Crina Anca, AFONSO Luis Urbano, MURTA Elsa, DE SA Maria Helena, Gilding Techniques in Religious Art Between East and West, 14th -18th Centuries, International
Journal of Conservation Science, Vol. 1, Issue 1, March 2010, pp. 47-62.
[2] LAMEIRA Francisco, O Retabulo em Portugal, das origens ao declínio, Promontoria Monografica Historia da Arte 01, Revista do Departamento de Historia, Arqueologia e Patrimonio
da Universidade de Algarve, Faro, 2005.
[3] SMITH Robert, A Talha em Portugal, Lisboa, Livros Horizonte, 1962.
[4] FERREIRA Silvia, A Talha – Esplendores de um Passado ainda Presente. Lisboa: Nova
Terra, Colecção Arte nas Igrejas de Lisboa, N.º 1, 2008.
[5] SERUYA Ana Isabel (ed.), Policromia: A Escultura Policromada Religiosa dos Sec. XVII
e XVIII – Estudo comparativo de técnicas, alterações e conservação em Portugal, Espanha
e Bélgica, Actas do Congresso Internacional, Lisboa 29-31 de Outubro 2002, Instituto
Português de Conservação e Restauro, Lisboa, 2004.
[6] SANDU Irina Crina Anca, GILT-Teller: An interdisciplinary multiscale study of gilding
techniques and materials in Portugal, 1500-1800, in Actas das VIII Jornadas de Arte e Ciência
- Conservação e Restauro de Artes Decorativas de Aplicação Arquitectónica, 29 September
de 2012, CITAR, Porto, 2013, pp.127-142.[EmLinha]Disponívelem:https://artes.porto.ucp.
pt/sites/default/files/files/artes/CITAR/VIII-Jornadas-Arte-Cieencia_compressed.pdf
[7] SANDU Irina Crina Anca, DE SA Maria Helena COSTA PEREIRA Manuel, Ancient “gilded”
art-objects from European cultural heritage: a review on different scales of characterization,
in Surface and Interface Analysis, Special Issue dedicated to Cultural Heritage, 43, no. 8/
August 2011, pp. 1134-1151.
[8] SANDU Irina Crina Anca, MURTA Elsa, NEVES Eva Raquel, PEREIRA Manuel, SANDU
Andrei Victor, KUCKOVA Stepanka, MAURICIO António, A comparative, multi-scale and
interdisciplinary study of gilding techniques and materials in two Portuguese Baroque “talha
dourada” complexes, ECR - Estudos de conservação e restauro (ISSN1647-2098), no 4/2013,
Porto, pp. 47-71, doi: 10.7559/ecr.4.3080.
[9] SANDU Irina Crina Anca, Gilt-Teller- a multimedia tool for the study and monitoring
of gilded wood carved decoration in Portuguese churches, ESRARC 2014 - 6th European
Symposium on Religious Art, Restoration & Conservation. Proceeding Book, edited by: Oana
Adriana Cuzman, Rachele Manganelli Del Fà, Piero Tiano (ISBN: 9788840443652), pages
218, 2014.
19
[10] SANDU Irina Crina Anca, PABA Francesca, MURTA Elsa, COSTA PEREIRA Manuel Francisco,
RIBEIRO Conceição, Travelling Beneath the Gold Surface – Part I: study and characterization
of laboratory reconstructions of Portuguese seventeenth and eighteenth centuries ground
and bole layers, e-conservation journal, issue 2, 2014, 43-63.
[11] SANDU Irina Crina Anca, MURTA Elsa, FERREIRA Silvia, COSTA PEREIRA Manuel
Francisco, CANDEIAS António, MIRÃO José, MIGUEL Catarina, PABA Francesca, More than
gold – an interdisciplinary, complementary study of gilding materials and techniques in
baroque altarpieces from Portugal, ESRARC 2014 - 6th European Symposium on Religious
Art, Restoration & Conservation. Proceeding Book, edited by: Oana Adriana Cuzman, Rachele
Manganelli Del Fà, Piero Tiano (ISBN: 9788840443652), pages 218, 2014.
[12] FERREIRA Silvia, MURTA Elsa, SANDU Irina Crina Anca, COSTA PEREIRA Manuel
Francisco, Os púlpitos barrocos da igreja de Nossa Senhora da Pena de Lisboa: um estudo
histórico, estilístico, técnico e material, Conservar Património (ISSN 2182-9942), no 17,
2014, pp. 1-16, doi:10.14568/cp2013009.
[13] SANDU Irina Crina Anca, MURTA Elsa, VEIGA Rita, MURALHA Solange Vania, COSTA
PEREIRA Manuel Francisco, KUCKOVA Stepanka, BUSANI Tito, An innovative, interdisciplinary,
and multi-technique study of gilding and painting techniques in the decoration of the Main
Altarpiece of Miranda do Douro Cathedral (XVII-XVIIIth centuries, Portugal), Miscroscopy
Research and technique, 76: 733-743, 2013, DOI: 10.1002/jemt.22224.
[14] KUCKOVA Stepanka, SANDU Irina Crina Anca, CRHOVA Michela, HYNEK Radovan, FOGAS
Igor, MURALHA Vania Solange, SANDU Andrei Victor, Complementary cross-section based
protocol of investigation of polychrome samples of a 16th century Moravian Sculpture by
optical, vibrational and mass spectrometric techniques, Microchemical Journal, 110, 2013,
pp. 538-544, DOI: 10.1016/j.microc.2013.07.002.
[15] SANDU Irina Crina Anca, MURTA Elsa, FERREIRA Silvia, VEIGA Rita, COSTA PEREIRA
Manuel Francisco, SANDU Andrei Victor, Between History and Science: Interdisciplinary
study of the gilded materials and techniques in the Baroque altarpieces of the Church of
Sorrow in Lisbon, InArt 2013 Conference – First International Conference on Innovation in
Art Research and Technology, Book of Abstracts, edited by António Candeias & Irina Crina
Anca Sandu (ISBN 978-606-624-441-1), 10-13th of July 2013, Evora, pp. 31-32.
Author’s curriculum vitae
Irina Crina Anca Sandu is a Researcher - Conservation Scientist with 18 years of experience (12 of post-doctoral activity, PhD in chemistry) in the field of investigation, diagnosis
and authentication of cultural heritage. She is author or co-author of 12 monographs, 2
book-chapters, more than 100 papers in peer-reviewed journals and conference proceedings
(corresponding author for 19 peer-reviewed papers in ISI indexed journals with H factor 11
and more than 360 citations).
20
Since the period of her university studies she has been involved in research projects and
international collaborations dealing with movable and immovable heritage. She is the coordinator (PI) of the project Gilt-Teller: um estudo interdisciplinar multi-escala das técnicas
e dos materiais de douramento em Portugal, 1500-1800” (PTDC/EAT-EAT/116700/2010)
funded by FCT in Portugal.
Contact:
irinasandu@uevora.pt
21
MATERIAL CHARACTERIZATION OF
GILDING AND PAINTING TECHNIQUES
OF A POST-BYZANTINE ICON
Maria Oliveira2,3 | M. Teresa Crespo3 | Sónia Costa1 | Cristina Barrocas
Dias1 | Ana Manhita1 | Ana Cardoso1 | Luís Dias1 | António Candeias1,2
1
HERCULES Laboratory, School of Sciences and Technology, Evora University, Évora, Portugal
2
José de Figueiredo Laboratory, General Directorate for Cultural Heritage, Lisbon, Portugal
3
Evora Museum, Alentejo Regional Directorate for Culture, Évora, Portugal
Abstract
This study aims to identify the materials used in the production of a post-byzantine icon
from the Museum of Évora’s collection. The icon, representing the “Emperor Constantine
and his mother Helen holding the Holy Cross” was once dated as being from the 10th
century. Throughout a multi-analytical approach, combining area exams with spectroscopic
techniques, this study tried to confirm its actual chronology. The results obtained revealed
that it is most likely an icon from the late 17th or 18th century.
Keywords
Orthodox art, Museum of Évora, sgraffito, punch work, dyes.
CARACTERIZAÇÃO MATERIAL DAS TÉCNICAS DE DOURAMENTO E PINTURA
DE UM ÍCONE PÓS-BIZANTINO
Resumo
Este estudo teve como objetivo a identificação dos materiais utilizados na produção de um
ícone pós-bizantino pertencente à coleção do Museu de Évora. Este ícone, representando o
“Imperador Constantino e a sua mãe Helena manifestando a Cruz”, foi datado como sendo
do século X. Através de uma abordagem analítica diversificada, combinando exames de área
com técnicas espectroscópicas, tentámos confirmar a sua datação. Os resultados obtidos
sugerem que será provavelmente um ícone dos finais do século XVII ou do século XVIII.
Palavras‑chave
Arte ortodoxa, Museu de Évora, esgrafito, puncionado, corantes.
CARACTERIZACIÓN MATERIAL DE LAS TÉCNICAS DE DORADO Y PINTURA
EN UN ICONO POSTBIZANTINO
Resumen
El presente estudio tuvo como objetivo la identificación de los materiales utilizados en la
producción de un icono pos bizantino perteneciente a la colección del Museo de Évora. Este
22
MATERIAL CHARACTERIZATION OF GILDING AND PAINTING TECHNIQUES OF A POST-BYZANTINE ICON
Maria Oliveira | M. Teresa Crespo | Sónia Costa | Cristina Barrocas Dias
Ana Manhita | Ana Cardoso | Luís Dias | António Candeias
icono tiene representado el “Emperador Constantino y su madre Elena manifestando la
Cruz” y había sido datado del siglo X. A través de un abordaje diversificado, combinando
exámenes de área con técnicas espectroscópicas, hemos intentado confirmar su datación.
Los resultados obtenidos han revelado que será probablemente un icono de finales del siglo
XVII o incluso del siglo XVIII.
Palabras clave
Arte ortodoxo, Museo de Évora, esgrafiado, puncionado, colorantes.
Introduction
The Museum of Évora was created by the Portuguese Government in 1915. One of its main cores
is the Public Library collection, mainly composed of Friar Manuel do Cenáculo’s private collection
(1724-1814) which gathers a very diverse and interesting group of objects that help us to understand his notable character. He was a close collaborator of the Marquis of Pombal (1699-1782),
minister of King Joseph I (1714-1777) and one of the most powerful men of his time. During the
Marquis’ term, Cenáculo was chosen for many political offices although the King’s death in 1777
and the consequence withdrawal of the Marquis of Pombal, he moved to Beja where he had been
nominated bishop in 1770, and dedicated to his activity as a collector and bibliophile. His main
passions were books and he contributed to the foundations of many Portuguese libraries, such as
the Public Library of Évora, founded in 1805. In this library, willed to the Archdioceses of Évora
after his death, he displayed not only books but also his private collection of art and “curiosities”,
which would later constitute the original core of the Museum of Évora.
Although he did not travel much abroad, he was able to gather a very interesting art collection,
mainly through gifts and ordered buys, testified by his many letters. In this diverse collection,
there is a unique object: an orthodox icon representing the “Emperor Constantine and his
mother Helen holding the Holy Cross” (figures 1 and 2).
Figure 1 - Emperor Constantine and his
mother Helen holding the Holy Cross (front),
ME211.
Figure 2 – Reverse of the icon “Emperor
Constantine and his mother Helen holding the
Holy Cross” shows the inscription Jesus Christus
Nike, ME211.
23
It is not known how this icon came to Évora, who offered it
or if it was bought. It is known that it belonged to Cenáculo’s
collection because he made a print of it in the last book he
published: “Graças concedidas por Christo no campo de
Ourique”, published in 1813 (figure 3). In this book, the
image appeared as “the painting of Constantine and Helen
manifesting the Holy Cross that appeared to the Emperor
to encourage him to the battle he won, like what happened
to our Monarchy Founder. Is in the same Museum of Évora”
(Cenáculo, 1813: Estampa Segunda). The interest of Cenáculo
in this icon might be precisely in its iconography because,
as it happened to Emperor Constantine before a battle, it is
Figure 3 – Print of the original
engraving plate (19th century),
ME2028.
believed that an image of Christ also appeared to the first king
of Portugal, D. Afonso Henriques before the important battle
of Ourique. Due to this symbolical significance, the cross with
the inscription “In hoc signo vinces” (similar to the one that
appears on the icon) was inscribed in Portuguese coins since the medieval ages until the
19th century. This detail, that is actually different from other icons (figure 4 and 5) with this
same theme, might have been what caught Cenáculo’s attention, although no reference to
this acquisition has been found in his diary or letters.
It would be only in 1882 that there would appear a new reference to this icon, when it was
chosen to include the “Portuguese and Spanish Ornamental Art retrospective exhibition” in
Lisbon. Back then it was identified as a wood piece, covered in gypsum, gilded and painted
with tempera, and dated as a 10th century byzantine icon. This date was established due
to the inscription at the back of the icon “IC-XC-NI-KA” (figure 2): “The characters at the
back offer, by their form and arrangement, the elements for the establishment of a date.”
Figure 4 – Icon of Constantine and St. Helen,
circa 1800, © Russian Icon Gallery.
Figure 5 – Icon of Constantine and St. Helen,
17th century, © Byzantine and Christian
Museum, Greece (BXM: 013233).
24
Constantine the Great was elected Cesar in 306 of our time, but the use of the phrase:
Jesus Christ won or winner (Jesus Christus Nike) only appears, for example, in the coins of
Leo V and Constantine VII (813 to 820).
On the obverse of the coins attributed to John I Tzimiskes (969 to 976) the letters IC-XCNI-KA can be found bypassing the cross angles exactly as it happens in the painting (…)”
(Pereira 1948: 276-277).
Therefore, in the subsequent collection inventories, this information about the materials
and the icon dating of the icon would be repeated without being questioned. This might be
explained by the lack of knowledge about this kind of art in Portugal, where it is very rare to
find artworks like these in museum collections. Probably due to all these reasons, this icon
was never analysed before and has mainly been kept in storage, unstudied for over a century.
More recently, amidst a research about Friar Manuel do Cenáculo’s collection, interest in this
icon was renewed. During carefully analysis of the icon stylistic characteristics, the sgraffito
decoration of the garments did seem a more recent production, as the ornaments were more
similar to those from the 17th and 18th centuries works (figures 4 and 5). However, a more
accurate conclusion could only be reached through a material identification of the icon.
Therefore, this study aimed to identify the materials used by the iconographer, in order to
confirm the date of its production, but also to allow a deeper knowledge about the production
techniques of this work of art.
For the material characterization a multi-analytical approach was used combining area exams
with spectroscopic techniques, non-destructively whenever possible.
Description
The depiction of “Emperor Constantine and his mother Helen holding the Holy Cross” is a
common representation in orthodox icons since their origin.
Constantine was the roman Emperor responsible for the Edict of Milan (313) that decreed
tolerance for Christianity in the empire. This Edict followed his victory over Maxentius, in
312, when Christ appeared to him, guaranteeing his victory if he used the sign of God in
the shields of his soldiers (the ChiRho). Helen, his mother, was always a Christian, and was
responsible for the discovery of the True Cross, the cross of Christ’s crucifixion, in Jerusalem.
The depiction of the True Cross became very common, mostly with Constantine and Helen
holding it, as it may be observed in this icon, for example.
In this icon, Constantine is on the right side of the cross and Helen on the left, as they are usually
displayed. They are wearing red imperial robes, with two different shades, with golden stylized
ornaments. These garments’ decorations are actually similar to some productions of the Melkite
Christians from Syria (17th-18th centuries)1, but this provenance is not possible to confirm.
1 Information gently suggested by Dr. Mariella Lobefaro (ICONE Association, Biella, Italy).
25
Both figures are wearing the loros, the imperial embroidered scarf. Constantine is depicted
with beard, as usual since the 9th century (Teteriatnikov 1995: 174), with an imperial crown
and holding a sceptre. Helen is wearing a green scarf covering her hair, with a crown on top.
She is holding a red flower, which is not very common in this iconography, and for that no
explanation was still found. They are holding a green medallion with a small golden cross
enclosed, with the Latin inscription “In hoc signo vinces” written in a red band surrounding the
medallion. The background is divided in three levels: the red ground, the gilded background
and the green sky, with some streamlined clouds. On the top of the icon, there is a small
semicircle in blue, with a few stars, that probably represents the Holy Spirit or the presence
of God. The names are written in Greek beside each figure.
In other icons with this same iconography, Constantine and Helen are depicted with a Latin
or an Orthodox cross, usually with the same height as them (figure 4 and 5). In this case it
presents a different cross, which is not common. Interestingly, the figures of Constantine and
Helen were many times used in church decorations as a way of displaying the cross, varying
its size in relation with the space where it should be depicted. Therefore, in some churches
in Cappadocia, due the architecture of the vaults, it is possible to find them holding a small
cross, enclosed in a medallion (Teteriatnikov 1995: 175) similar to the one represented in
this study that shows an interesting variety of depictions of the Holy Cross.
As for the artistic techniques of this icon, the iconographer used the sgraffito technique on the
garments and punch work on the saints’ halos, on top of the red floor, below the medallion
with the cross, and also all around the edges. The artist also exploited the variety of tones
and shades through the use of strokes of brush, conferring a more volumetric shape namely
in Constantine and Helen’s face or in the green sky.
The used techniques and the iconography of this icon follow the traditional rules of production
of these devotional objects defined by specific treaties, such as the 18th century treaty of
Dionysius of Fourna. These treaties are still used among the Orthodox Church as icons’ stylistic
characteristics remained mainly unchanged and its contemporary production still obeys the
same strict rules, since they preserve their ritual importance. However, in the history of the
production of icons, there are small details that would evolve during the centuries, not only
reflecting the styles and artistic features of each period, but also the use of new available
materials (pigments, dyes, binders).
Experimental
Area exams were used for the first approach to the material characterization: ultraviolet
fluorescence photography, to identify possible restorations; radiography, to analyse the inner
structure and painting composition; infrared reflectography, to reveal possible preparatory
drawings.
26
Point analysis involved the use of in situ X-Ray Fluorescence using a Bruker Tracer III SD
with a Rhodium target and a silicon drift detector (SDD) used as a preliminary elemental
characterization of materials used in the icon. The resolution was 152 eV (Mn Ka -FWHM at 6.4
keV) and all the spectra were collected in S1PXRF software developed by Bruker. Instrumental
settings were: 20 KeV, 35 μA and an acquisition time of 90 second for each point. A Ti filter
was used, which did not allow Rh L line from the tube to reach the sample. This eliminates
superimposition between Rh L lines and S, Cl, and P K lines. A vacuum pump was used to
increase the sensibility of light elements. The spot of the analysis is 7 square millimeters.
ARTAX 7.0 was used for qualitative spectra analysis.
Micro samples were collected and mounted in epoxy resin for cross-section observation. The
cross-section observation by Optical Microscopy (OM) was performed with a stereo zoom
microscopy Leica M205C, with camera Leica DFC290HD for image acquisition. The material
characterization of the different strata, including ground layers, bole, golf leaf and paint
layers, was performed with a Scanning Electron Microscope HITACHI S-3700N with energy
dispersive X-ray spectrometry with a Bruker Xflash 5010 SDD spectrometer (SEM-EDS). The
samples were also analysed by a confocal µ-Raman spectroscopy instrument from Horiba
Xplora (638 and 785 nm laser, spatial resolution 1 µm, spectral resolution 5 cm-1, maximum
power 1 mW, CCD with 1026 x 256 pixels). For the analysis of the green colour of the cross,
Fourier Transform Infrared spectroscopy (µ-FTIR) was performed using a Bruker spectrometer
Tensor 27 model at medium infrared region (MIR). The spectrometer uses a microscope
Hyperion 3000 controlled by software OPUS 7.2 from Bruker, with a Mercury Cadmium Telluride detector. The sample was analysed in transmission mode using a 15x objective and a
diamond compression microcell EX’Press 1.6 mm, STJ-0169. The spectra were performed in
the 4000-600 cm-1 region, with 64 scans and spectral resolution of 4 cm-1.
The green and the blue colour samples were analysed with pyrolysis gas chromatography mass
spectrometry (PY-GC-MS) with TMAH derivatization. Liquid chromatography with diode array
detector and mass spectrometry (LC-DAD-MS) was used for the analysis of organic material.
Figure 6 – Radiography of the icon.
27
Results and discussion
Support
Given that the icon is painted in both sides, radiography was performed to analyse the
support (Sotiropolou, 2010:879). As seen in figure 6, the support is composed of a single
wood panel, without assemblies or slats, which often appear on icons to prevent cracking
due to the hygroscopic movements of the wood. The radiography also allowed us to find
that the support is in a very good conservation condition, without cavities provoked by
wood boring insects.
Ground
Figure 7 - SEM-EDS of ground layer of CH7 sample.
By optical microscopy (OM) it was visible that the ground layer has white appearance and
was applied over the entire front surface. By OM it was not possible to identify the different
strata in this white layer. The higher thickness was around 180µm. Although the treaties
(Dionysius of Fourna, Francisco Pacheco, Filipe Nunes) recommend the application of several
strata, they can never be distinguishable through this technique (Barata, 2012:44). This
could be due to the use of sandpaper and the successive hot applications of the material
which promotes a fusion of the materials from different applications (Cardoso 2014:173).
Figure 8 - µ-Raman spectra of gypsum of CH2 sample Peak identification: 414m, 1008vs
(Wavelength 785 nm, 6.5 mW, 10 s).
28
Nevertheless, SEM-EDS analysis confirmed the presence a layer composed of calcium
associated with sulphur, suggesting calcium sulphate, with lamellar homogenous particles
(figure 7). Some Si, Al and Cl were also identified but in very residual proportions. Due to
its natural, origin those minor elements can be associated to gypsum (Coroado, 2013:82).
Although some of them can be helpful in material provenance studies (Gómez, 2005:48),
these elements could also be residual from the technical procedures, such as polish materials
(Le-Gac 2015:73).
The µ-Raman results showed the presence of dihydrate calcium sulphate (CaSO4•2H2O) as
showed in figure 8.
Above the ground layer the artist projected the composition with a preliminary drawing,
visible through infrared reflectrography. The drawing was evident on the flesh tones only
(faces and hands of the figures). The fact that the drawing is not visible in other areas of the
icon does not mean that it does not exist. There are limitations related to the reflectography
technique (Weiner 1999) and it is just possible to detect drawing in areas where there is no
bole layer and gold leaf above it.
Figure 9 - SEM-EDS of bole layer of CH1 sample.
Bole
The bole layer has an orange colour and is very homogeneous. The layer is applied over the
ground, except on the flesh areas. The bole layer was applied even under the cloudy green
sky, which is not gilded, which could be interpreted as regret during the gilding execution
or just a way to simplify the whole process. It was perceptible by EDS that this layer is
composed mainly of iron (Fe), aluminium (Al) and silicon (Si) (figure 9) and a very dispersive
quantity of particles of titanium (Ti) were also traceable, usually associated in clay minerals.
Gold leaf
The gold leaf was applied over the bole layer except in the cloudy sky area. An exception was
identified in the cross-section of the green cross in the middle of the icon, which is gilded
although no bole was detected. This might be due to the proximity of the flesh tones, or it
29
could be a regret: the artist projected not to gild but, at the end, decided otherwise. The
SEM-EDS spectra collected from the gold alloy show the presence of gold (Au) and silver
(Ag). The semi-quantitative analysis undertaken in three different points of three samples
revealed a mass proportion of 95,5% of gold and 4,5% of silver in average. This average
demonstrates the use of a very high purity gold leaf of about 23 karats.
Paint layer
Figure 10 - PY-GC-MS chromatogram of blue sky sample. Peak identification as follows: 1-azelaic
acid; 2 – palmitic acid; 3 – stearic acid; 4 – indigotin (TMAH derivative).
The icon was painted after the gilding process. Gold was left in the middle part of the
background, in the halos of the figures and in the frame. In these cases, the punch work
was used to create different shades of gold.
The study involved the characterization of all the colours used: green, blue, red, white
and black. The flesh tones were not considered because by UV photography was possible
to perceive that Helen’s face was overpainted and Constantine’s face was in a very good
condition for sampling (Sandu, 2006).
Two different greens were used, one for the cloudy sky and another for the central cross
and some other details. The first one is opaque and mixed with white to create different
grades of light and shadow. By SEM-EDS, a copper-based pigment was identified in a mixture
with lead white and calcium carbonate. Malachite was identified by µ-Raman spectroscopy.
The second green is translucent, used as a lake, allowing the gold layer to appear below.
Through SEM-EDS a copper-based pigment was identified but analysis by µ-Raman and
30
µ-FTIR were not conclusive about the chemical nature of the pigment, for it could be, for
example, copper resinate.
The white colour present in the loros is calcium carbonate, identified through SEM-EDS.
Figure 11 - LC-DAD-MS chromatogram of the red sample from Constantine’s garments.
Peak identification: 1-carminic acid.
For the blue colour at the round starry sky at the top, the results by SEM-EDS did not
reveal any element compatible with an inorganic blue chromophore and therefore were not
conclusive regarding the blue pigment, allowing only the identification of the white pigments
used in the mixture: lead white and calcium carbonate, based on the identification of Pb
and Ca and the absence of S. PY-GC-MS allowed the identification of indigo, confirming the
organic nature of the blue colour (figure 10).
Three different reds were analysed: the floor, Helen’s garment and Constantine’s garment.
The first one was identified by SEM-EDS as an aluminosilicate with iron oxide in a mixture
with lead white and calcium carbonate. The red in Helen’s garment is composed of mercury,
which suggests the use of vermillion. The red in Constantine’s garment was analysed through
LC-DAD-MS due to its translucent appearance that suggested an organic compound. The
results showed the presence of carminic acid, the main constituent of cochineal lake (figure
11). Kermesic and Flavokermesic acids are minor constituents, acting as markers of Polish and Armenian cochineal (Eastaugh, 2004:118). Since no evidence of these acids was
found, it is possible that the type of cochineal used was South American cochineal, which
31
was only introduced in Europe in the late 16th century by Spanish navigators. The pigments
and dyes identified in the paint layer are in consonance with other analytical studies about
icons (Avillez, 2008; Karapanagiotis, 2008; and Daniilia, 2002).
The binders were analysed in the green area of the cross and the blue sky. No evidence of
proteinaceous binder was found through µ-FTIR. Through PY-GC-MS the presence of linseed
oil was identified based on the palmitic to stearic (P/S) ratio, which was 1,57 for the blue
sky sample and 1,71 for the green sample.
Conclusion
The results of the analyses performed in this study allowed to verify that all the materials
used by the iconographer are frequent in the production of icons throughout the last five
centuries. The material characterization of this icon of “Emperor Constantine and his mother
Helen holding the Holy Cross” identified gypsum in the ground layer and aluminosilicate
containing iron in the bole layer. In the paint layer, with linseed oil as binder, white lead,
calcium carbonate, iron oxide, vermillion and malachite were identified as pigments and
indigo and cochineal as dyes used in the production of lakes.
Therefore, the identification of what seems to be South American cochineal, introduced
in Europe by Spanish navigators, locates the execution of the icon after mid-16th century,
revoking the 10th century date originally attributed. Overall, this data corroborates the art
historian’s opinions that according to its stylistic characteristics, like the garments’ ornaments,
this is a post byzantine icon probably produced between the 17th and the 18th centuries,
perhaps a contemporary work of Friar Manuel do Cenáculo.
This study also confirmed the importance of the material characterization as an important
tool for a more accurate knowledge of artworks in museum collections, helping to fulfil one
of the main purposes of these institutions: the research.
References
AVILLEZ, M., VOURUOPOULOU C. “ConservationConservation of a Greek icon. Technological
and methodological aspects”. In E-conservation, 2008. [consulted: 21-05-2015] http://
documents.mx/documents/e-conservation-magazine-6-55846622d5510.html#pf25
BARATA, C.,CRUZ, A.J.,ROCHA, F. “Sobre os materiais utilizados na talha da época barroca
do noroeste de Portugal – primeiros resultados”. In Actas do I Encontro Luso-Brasileiro de
conservação e restauro. Porto: Universidade Católica Portuguesa, 2012, pp. 40-50.
CARDOSO, I. “As camadas preparatórias em retábulos e esculturas policromadas portuguesas.” In Actas do colóquio internacional: As preparações na pintura portuguesa nos séculos
XV e XVI. Lisboa: Overprint, 2013, pp.167-176.
32
CENÁCULO, M. Graças concedidas por Christo no Campo de Ourique, acontecidas em outros
tempos e repetidas no actual, conforme aos desenhos de suas idades. Lisboa: Impressão
Régia, 1813.
COROADO, J., ANTUNES,V.,SERRÃO,V.,OLIVEIRA,M. J., DIAS, L., CANDEIAS, A., MIRÃO, J.,
CARVALHO, I., SERUYA, A. I. “Presença de celestite em retábulos portugueses”. In Actas
do Colóquio Internacional: As preparações na Pintura Portuguesa nos séculos XV e XVI.
Lisboa: Overprint, 2013, pp. 75-83.
DANILIA, S., BIKIARIS, D., BURGIO, L., GAVALA, P., CLARCK, R., CHRYSSOULAKIS, Y. “An
extensive non-destructive ans micro-spectroscopic study of two post-Byzantineoverpainted
icons of the 16th century”. In Journal of Raman Spectroscopy. Wiley InterScience volume
33, issue 10 (2002) pp. 807-814 [consulted: 18-05-2015] http://onlinelibrary.wiley.com/
doi/10.1002/jrs.907/epdf
EASTAUGH, N., WALSH, V., CHAPLIN, T., SIDALL; R. Pigment compendium. A dictionary of
historical pigments. Oxford: Elsevier Butterworth-Heinemann, 2004.
GÓMEZ, S. Las preparaciones de yeso en la pintura sobre tabla de la escuela española.
Ph.D.dissertation. Madrid: Faculdad de Bellas Artes, Universidad Complutense de Madrid,
2005.
KARAPANAGIOTIS, I.; WEI, S., DANILIA, S., STASSIONOPOULOS, S. “Analytical investigation
of painting techniques used in icons of the Cretan school of iconography”. In 9th International
Conference on NDT of Art. Jerusalem: NDT, 2008, pp. 1-9. [Consulted: 30- 04 – 2015]
http://www.ndt.net/article/art2008/papers/223Karapanagiotis.pdf
LE GAC, A. “For leveling, polishing and burnishing polychrome artworks between the 16th
ans 18th centuries, in Portugal: tools under scrutiny”. In: GILT-EnArt 2015 International
Conference on Gilding Materials and Techniques in European Art. Book of abstracts. Évora:
PIM, 2015, pp. 73-74.
SANDU, I. C. A., BRACCI, S., SANDU, I. Instrumental Analyses used in the authentication
of orthodox icons. Comparison between two icons of XIXth century. Bucuresti: Revista de
Chimie, 59, nº8 (2006), pp. 855-866. [Consulted: 29-04-2015] http://www.revistadechimie.
ro/pdf/SANDU%20I%20C.pdf
STOTIROPOULOU, S., DANILIA, S. “Material aspects of icons. A review on Physicochemical studies of greek icons”. In Accounts of chemical research. American Chemical Society,
Volume 43, issue 6 (June 2010), pp. 877-887.
PEREIRA, Gabriel. “Exposições de Arte Ornamental”. In Estudos Eborenses, vol. II. Évora:
Edições Nazareth, 1948.
POPOVA, O., SMIRNOVA, A., CORTESI, P. Icone, Guida completa al riconoscimento delle
icone dal VI secolo a oggi. Milano: Guide Cultura, Mondadori Electa, 2003.
33
TETERIATNIKOV, Natalia. “The True Cross Flanked by Constantine and Helena. A study in the
Light of the Post-Iconoclastic Re-evaluation of the Cross”. In Deltion Chae. Athens: National
Documentation Centre, 18, series 4 (1995).[consulted: 26 – 04 – 2015] http://ejournals.
epublishing.ekt.gr/index.php/deltion
WEINER, Chad. Improved acquisition Tecnique of Underdrawings in oil-paintings using
IR-Reflectography. Rochester, NY: Center for Imaging Science, Rochester Institute of Technology, 1999 [consulted: 15.06.2015]. http://www.cis.rit.edu/research/thesis/bs/1999/
weiner/thesis.html
Ackowledgments
This work has been supported By Fundação para a Ciência e Tecnologia trough grants:
SFRH/BI/51521/2011 and SFRH/BI/51531/2011.
Maria Oliveira has a degree in Conservation and Restoration with the specialization in
gilded and polychrome wood and has a master degree in Museology. Is a grant researcher
of conservation and restoration at the Museum of Évora since 2011, where she has been
studying mainly the wood sculpture collection, in collaboration with the Hercules laboratory
of the University of Évora.
Contact:
carmo.nunes.oliveira@gmail.com
Teresa Crespo has a degree in History of Art and a master degree in Museology. Is a grant
researcher at the Museum of Évora since 2011, where she has been studying the artistic
collection of Friar Manuel do Cenáculo.
Contact:
teresa_crespo@hotmail.com
34
God is in the detail. Gold, silver and polychromy
Tiago Dias1 | Michèle Portela3 | M. José Oliveira3 | Elsa Murta3 | Cristina
Barrocas Dias4 | Vítor Serrão2
PhD Candidate with grant from Fundação para a Ciência e Tecnologia at the School of Arts
1
and Humanities, Lisbon University
2
Artis- IHA-FLUL - Art History Institute, School of Arts and Humanities, Lisbon University,
Portugal
3
José de Figueiredo Laboratory, General Directorate for Cultural Heritage, Lisbon, Portugal
4
Hercules Laboratory, School of Sciences and Technology, Evora University, Évora, Portugal
Abstract
The visible polychromy of a wooden sculpture representing St. John the Evangelist, from
Museu Nacional de Arte Antiga, Lisbon (Portugal) presents several techniques that complement each other on the creation of a sumptuous estofado. This case-study allowed the
survey on gilding, silvering and polychromy practices, and observations on their execution
are briefly reported and documented with results from a multi-analytical approach. Examination included digital photomicrography and the observation of micro-samples cross-sections,
while material identification resorted to several analytical methods that included scanning
electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) and
X-ray diffraction (XRD).
Keywords
Polychromy, gilding, silvering, estofado, pastiglia, sgraffito, punchwork.
Deus está nos detalhes. Ouro, prata e policromia
Resumo
A policromia visível de uma escultura em madeira representando S. João Evangelista, do
Museu Nacional de Arte Antiga, Lisboa (Portugal) apresenta várias técnicas que se complementam na criação de um sumptuoso estofado. Este caso de estudo permitiu o exame
de processos de douramento, prateamento e policromia, sendo as observações da sua
execução reportadas e documentadas com os resultados de uma abordagem multi-analítica.
O exame incluiu fotomicrografia digital e observação de cortes transversais de amostras
de policromia, recorrendo a identificação material a vários métodos analíticos, incluindo
microscopia eletrónica de varrimento associada a espectroscopia raios-X por dispersão de
energia (SEM-EDS) e difração de raios-X (XRD).
Palavras‑chave
Policromia, douramento, prateamento, estofado, pastiglia, esgrafitado, puncionado.
35
Tiago Dias | Michèle Portela | M. José Oliveira | Elsa Murta | Cristina Barrocas Dias | Vítor Serrão
Dios está en los detalles. Oro, plata y policromía
Resumen
La policromía visible de una escultura de madera representando a San Juan Evangelista,
de Museu Nacional de Arte Antiga, Lisbona (Portugal) presenta varias técnicas que se
complementan en la creación de un estofado suntuoso. Este estudio de caso permitió el
examen de procesos de dorado, plateado y policromía, y las observaciones a su ejecución
son reportadas y documentadas con resultados del enfoque multi-analítico. El examen
incluyó fotomicrografía digital y observación de secciones transversales de muestras de
policromía, la identificación material recurriendo a diversos métodos analíticos, incluyendo
microscopía electrónica de barrido con espectroscopia de rayos X (SEM-EDS) y difracción
de rayos X (XRD).
Palabras clave
Policromía, dorado, plateado, estofado, pastillage, esgrafiado, burilado.
Introduction
Following the poster presentation at GILT-EnArt 2015 on the case-study of the re-polychromy
of a wooden sculpture comprising several techniques, this article provides more data and
further discussion.
The creation of polychrome sculpture was a corporative and collaborative activity that
resulted from joint efforts of several artists and took advantage of each one’s particular
skill to create meaningful religious works of art (Bassett and Alvarez 2013). The carved
shapes of the sculpture were further enhanced by the painter-gilder’s work through the
choice of materials and colours. Depending upon the artist’s expertise, an enhancement on
the realism and splendour of the sculpture could be achieved, while imparting an entirely
new set of iconographic connotations that deepened the image’s significance (Falcão and
Afonso 1997:114).
Although most artistic and historic studies value the sculptor´s work, often overlooking other
artists’ contributions, significant efforts have been recently implemented to reattribute the
rightful importance to the painter-gilder’s role, allowing for a holistic approach to the work
of art (Gómez Espinosa et al. 2004).
The object under study is a small polychromed wooden sculpture (47 x 20,5 x 10 cm) that
represents St. John the Evangelist (figures 1 and 2), and it constitutes a good example on how
exquisite polychromy technical skills contribute to the image’s artistic value. This sculpture
from Museu Nacional de Arte Antiga (MNAA), Lisbon (Portugal), of unknown authorship, is
dated from the late 17th century, and has been studied in Portugal, at Laboratório José de
Figueiredo (LJF-DGPC), Lisbon, with the analytic support of Laboratório HERCULES, Évora.
36
The sculpture’s visible (re)polychromy in the drapery areas, which presents an elaborate
estofado, is the main focus of this case-study. Estofo and Estofado are the Portuguese terms
that mean, respectively, fabric or clothes and their representation through polychromy
(Bluteau 1728:III-325; Ferreira-Alves 2004:18). Several techniques can be combined in
the creation of these often elaborate and lavish fabrics, such as: sgrafitto, punching (Nunes
1615:69), glazing and brush-tip painting (Gómez Espinosa et al. 2004:44; Serck-Dewaide
et al 2004). In the sculpture under study many of these techniques were used to create
St. John´s garments, which will be further detailed in an attempt to trace back the steps
on their creation.
Figures 1 and 2 - São João Evangelista, front and back side. Polychrome wood sculpture
(47 x 20,5 x 10 cm), MNAA, esc. 597. Images acquired by Luis Piorro, LJF-DGPC.
Analytical methodology
The study of the polychromy started with close observation and photographic records.
Surface details providing technical information were registered through Digital Photomicrography (DP) using a handheld digital microscope Dino-lite Pro AM413T, which allowed
detail measurements.
37
Selected areas of the polychromy were micro sampled and the samples were mounted
on clear epoxy resin (EpoFix Struers) and polished to provide observable cross sections.
Optical microscopy (OM) observations were obtained by the dark-field microscope Leica
DM2500 coupled with the digital camera Leica DFC290 HD that provided the corresponding
photographic documentation.
Scanning Electron Microscopy (SEM) images were made by using the Hitachi 3700N scanning electron microscope coupled to the Bruker X Flash 5010 SDD X-ray energy dispersive
spectrometer (EDS), used for point analysis and elemental mapping, with the resolution of
129 eV for Kα of Mn, and QUANTAX micro analysis system. The analyses were made at 20
kV under variable pressure (40Pa).
The characterization of crystalline phases was made by using a micro-diffractometer D8
Discover of Bruker AXS with area detection system (GADDS), equipped with Cu-kα anode,
göbel mirror, HiStar detector and 1 mm diameter collimator. The angular range considered
varies between 8o and 70o and the acquisition time was 1800 s with a step of 0.02o. The
tension and the current intensity applied to the tube were 40 kV and 40 mA, respectively.
Phase identification was made through EVA software (version 2) of Bruker AXS using the
files of the international database PDF-ICDD.
Beneath the surface
The sculpture of St. John the Evangelist was carved in wood identified as oak wood (Quercus
sp.), through morphological characterization (Esteves 2014). During the polychromy study
it was noticeable that the visible polychromy covered a previous one, partially visible on
the lacunae areas, which was later confirmed by examining micro-samples cross-sections
(figures 3 and 4). Although the study focuses on the latter polychromy – the visible one – a
few observations can be made on these underlying layers.
Surveying the samples where this first polychromy is visible, it is possible to determine that
the multilayered structure is consistent with water-gilding, where ground layers of gesso
and red bole are set as base for the gold leaf.
EDS elemental mapping allowed for the identification of the gesso layers by the presence of
S and Ca, and the bole layer, by the detection of Al, Si and Fe matching an aluminosilicate
clay rich in iron oxides. The EDS point analysis on the gold leaf allowed the identification of
a ternary Au-Cu-Ag alloy with a gold content ranging from c. 22,5 kt to 23 kt.
It was also observed that the burnished leaf was covered with coloured layers, which could
indicate the use of the sgraffito technique. Samples from the tunic present a blue colour
(possibly an azurite based pigment given the high concentration of Cu) (figure 3) and
samples from the mantle have a red layer over the gold leaf (figure 4).
38
Visible
polychromy
Pre-existing
polychromy
Figure 3 – Sample cross section from the tunic
area where it is possible to observe the overlapped
polychromies with metal leaves, and a blue layer
on the pre-existing polychromy. Reflected light OM,
100x. Image acquired by Tiago Dias.
Figure 4 – Sample cross section from the
mantle with a red layer on the pre-existing
polychromy. Reflected light OM, 100x. Image
acquired by Tiago Dias.
A sculpture´s second skin
On the second and currently visible polychromy, different materials and techniques were
applied on the drapery to create an intricate estofado. Raised gesso motifs (pastiglia) were
made to add further volume and decorate the tunic and mantle, and the surfaces were
gilded and silvered. The mantle was gilded with gold leaf and painted, and elaborate sgraffito patterns were scraped, while the tunic received a green glaze that partially covered the
silvered surfaces. A yellow coloured glaze was also used over gilded areas, complementing
the delicate punchwork compositions. Finely detailed brush tip painting of floral motifs and
other finishing touches brightened up the whole polychrome decoration.
Following what is believed to be the execution sequence in which the techniques were carried
out, the most noteworthy observations made on each one are described next.
Preparatory layers
The ground is arranged in a multilayered structure, according to the traditional water-gilding
practice. The white ground layer is composed of calcium sulphate dihydrate (gypsum),
identified by X-ray diffraction (figure 5). In this case no underlying layer of anhydrite (gesso
grosso) was detected, although it is commonly referred to be used as the first ground layer
and then followed by gypsum. This gypsum should be of synthetic nature (gesso fino), a
higher quality of gesso produced by re-hydration of anhydrite, presenting small even particles
of lamellar shape (Cardoso 2013:173).
For a new polychromy to be made over a pre-existing one, there was no need to create a
thick ground layer, which can explain the single use of gypsum. Nevertheless, the resource
to this finer gesso may reflect the great care on the preparation of this polychromy. Although
the gypsum might have been applied in several consecutive layers, it is not possible to
distinguish between each of them, since the need to apply these preparatory layers while
39
warm could cause them to fuse together. The measured samples show that the layer thickness varies from 71 µm to 261 µm.
500
1000
900
800
400
700
300
Lin (Cps)
Lin (Cps)
600
500
400
200
300
200
100
100
0
8
10
20
30
40
50
60
0
70
8
2-Theta - Scale
Figure 5 – XRD diffractogram identifying gypsum.
XRD analysis by M. José Oliveira, LJF-DGPC.
10
20
30
40
50
60
70
2-Theta - Scale
78-13-12 cam dourada [001] - File: 78-13-12_Dourado_01 [001] .raw - Type: 2Th alone - Start: 8 .000 ° - End: 70 .500 ° - Step: 0 .020 ° - Step time: 1800 . s - Temp .: 25 °C (Room) - Time Started: 0 s - 2-Theta: 8 .000 ° Operations: X Offset 0 .083 | Background 1 .000,1 .000 | Range Op . Merge | Import [001]
00-033-0311 (*) - Gypsum, syn - CaSO4·2H2O - Y: 49 .25 % - d x by: 1 . - WL: 1 .54184 - Monoclinic - a 6 .28450 - b 15 .20790 - c 5 .67760 - alpha 90 .000 - beta 114 .090 - gamma 90 .000 - Base-centered - C2/c (15) - 4 01-086-2237 (A) - Quartz - SiO2 - Y: 9 .70 % - d x by: 1 . - WL: 1 .54184 - Hexagonal - a 4 .91300 - b 4 .91300 - c 5 .40400 - alpha 90 .000 - beta 90 .000 - gamma 120 .000 - Primitive - P3121 (152) - 3 - 112 .964 - I/Ic PDF
00-058-2001 (I) - Kaolinite-1A - Al2Si2O5(OH)4 - Y: 8 .26 % - d x by: 1 . - WL: 1 .54184 - Triclinic - a 5 .15500 - b 8 .95120 - c 7 .40830 - alpha 91 .698 - beta 104 .836 - gamma 89 .832 - Primitive - P1 (1) - 2 - 330 .299 - F30
00-001-1174 (D) - Gold - Au - Y: 33 .78 % - d x by: 1 . - WL: 1 .54184 - Cubic - a 4 .06400 - b 4 .06400 - c 4 .06400 - alpha 90 .000 - beta 90 .000 - gamma 90 .000 - Face-centered - Fm-3m (225) - 4 - 67 .1214 - F9= 12(0 .08
78-13-12 cam prep [001] - File: 78-13-12_Prep_01 [001] .raw - Type: 2Th alone - Start: 8 .000 ° - End: 70 .000 ° - Step: 0 .020 ° - Step time: 1800 . s - Temp .: 25 °C (Room) - Time Started: 0 s - 2-Theta: 8 .000 ° - Theta: 1
Operations: X Offset 0 .075 | Background 1 .000,1 .000 | Range Op . Merge | Import [001]
00-033-0311 (*) - Gypsum, syn - CaSO4·2H2O - Y: 70 .90 % - d x by: 1 . - WL: 1 .54184 - Monoclinic - a 6 .28450 - b 15 .20790 - c 5 .67760 - alpha 90 .000 - beta 114 .090 - gamma 90 .000 - Base-centered - C2/c (15) - 4 -
Figure 6 – XRD diffractogram identifying gypsum,
kaolinite and quartz. XRD analysis by M. José
Oliveira, LJF-DGPC.
Although all the bole layers seem to have a similar base composition of aluminosilicate clay,
confirmed by the XRD analysis through the identification of kaolinite and quartz (figure 6),
they differ according to the metallic leaf they are to support. While the bole in gilded areas
has a warmer orange colour, with the detection of Fe suggesting a high concentration of
iron oxides (figure 7), the white bole underlying the silver leaf shows a reduced amount of
Fe on elemental mapping (figure 8). The average thickness for the orange bole layer is c.
20 µm, while for the white one is c. 24 µm.
The intentionality of using different coloured boles, for different kinds of metal leaf, reveals
great attention to the final outcome, since the silvered areas would become lighter by the
use of a white substrate instead of a reddish one.
Figure 7 – 2D elemental mapping
(Al, Si, K, Fe) by EDS analysis of burnished
gilding over a red bole sample. Fe distribution
indicates the concentration of iron oxides. SEMEDS analysis by Luis Dias, HERCULES.
Figure 8 – 2D elemental mapping
(C, Al, Si, Fe) by EDS analysis of burnished
silvering over a white bole sample. The low Fe
distribution on the top bole layer reveals low
concentration of iron oxides. SEM-EDS analysis
by Luis Dias, HERCULES.
40
Raised gesso – Pastiglia
Several raised elements were built up with gypsum, with the pastiglia technique, and further
complemented with punchwork to represent passementerie or lace motifs (figure 9). These
elements consist mostly of “C” shapes on the mantle and leaf shapes on the tunic. They
must have been created freehandedly with several repeated brush applications of the warm
gesso preparation until the desired shapes and relief were achieved (Martínez 1997:175;
Le Gac 2004:80), or by means of a piping bag (García 2002:244). The mantle’s hem also
presents some bead shapes that could have been achieved by dripping the gesso. The boles
were applied after the execution of these gesso elements (figure 10).
Figure 9 - Details of the raised pastiglia
motifs on the hem of the mantle. Image
Figure 10 - Composite image of sample cross
section of the pastiglia work. Reflected light OM,
100x. Image acquired by Tiago Dias.
Gilding
The use of metal leaves followed the traditional water-gilding method for both gold and
silver, allowing the surfaces to be burnished to achieve a high sheen (figure 11). The attained
smoother surface also enabled and facilitated the execution of the estofado techniques,
providing a flat surface to paint, scrape and punch with less risk to drag out any metal
leaf. So the mantle, the greater part of the gilded surface where these techniques were
to be executed, presents burnished gold leaf. The sandals’ straps are the only areas left
unburnished, likely to achieve a differentiated matte finish (figure 12).
The gold leaf used is a ternary Au-Cu-Ag alloy, as indicated by EDS analysis. With a gold
content from 94,25 wt% to 97,41 wt%, it corresponds to a gold leaf ranging from 22,5 kt
to 23 kt (figure 13).
41
Figure 11 – Details of
burnished gilding, hem
of the mantle. Image
Figure 12 – Detail of
unburnished gilding, sandal´s
strap. DP c.60x. Image
Figure 13 – SEM-EDS spectrum of
the gold leaf indicating the ternary
alloy Au-Cu-Ag. SEM-EDS analysis by
Luis Dias, HERCULES.
Silvering
Although the artists at the time might have known that silver leaf is much less stable
than gold, tarnishing quickly if left unprotected, it was still in usage (Gómez Espinosa
et al. 2004:43; Serck-Dewaide et al 2004:136). Its high reflection index, about 95% of
incident light (Rodríguez 1999:746), would provide extremely shiny white surfaces, being
also favoured as a base for transparent to semi-opaque coloured glazes for the creation
of metallic colours, especially cooler hues, since its white shine would not interfere on the
final look of blues and greens as much as if gold leaf was used.
The tunic was water-silvered following the same processes used on the gilded areas. As
previously reported, on the areas where silver leaf was to be laid a white bole was applied,
thus reinforcing its final “whiteness”. All the silvered areas must have been burnished,
although the widespread tarnishing makes it difficult to assess.
The larger part of the tunic was covered with a green glaze, while only the pastiglia elements on the collar and hem and the small punched flower compositions were left unglazed,
creating what must have been a suggestive colour contrast (figure 14).
Figure 14 – Burnished silvering
on raised gesso motifs, hem of the tunic.
Image acquired by Tiago Dias.
Figure 15 – SEM-EDS spectrum of the silver
leaf, the presence of chlorine indicates the
formation of silver degradation products.
SEM-EDS analysis by Luis Dias, HERCULES.
42
Figure 16 – Detail of burnished silvering under
green glaze, the leaf tears show the white bole.
DP c.60x. Image acquired by Tiago Dias.
Figure 17 – Tarnished silvering on raised gesso
motifs, tunic´s collar, with visible wear caused by
abrasion, which reveals the preparatory layers.
The high reactivity of silver with atmospheric compounds, especially those containing sulphur
and chlorine, can lead to its irreversible degradation (Homem 2013). In this case EDS point
analysis detected the presence of Cl on the 24 kt silver leaf (figure 15). The unglazed areas
now appear completely dark and dull, and even the glazed portions of silver leaf seem to
have tarnished, given the dark stains that surround the cracking of the glaze (figure 16).
This degradation permanently changed the painter-gilder’s intent. And inadequate cleaning
that removed the tarnished silver seems to have been carried out on several of these areas,
partially exposing the white bole and gypsum preparatory layers (figure 17).
Sgraffito
The sgraffito technique was used only on the mantle, over the gold leaf. In order to produce
the motifs the burnished gilding was painted, leaving the mantle’s hem unpainted. The matte
appearance of colours might point to the use of the tempera technique, most often used
for sgraffito (Nunes 1615:69; Serck-Dewaide et al 2004:148). A red colour was applied on
the outer surface, where the presence of Hg in EDS analysis indicates the use of vermillion
(mercury sulphide, HgS); and a pink layer was applied on the inner side where the presence
of Pb alongside Hg points to a mixture of vermillion and lead white (basic lead carbonate,
2PbCO3·Pb (OH)2).
While on the outer side of the mantle, a floral motif was designed (figure 18), on the inner
side a fish-scale pattern was chosen (figure 19).
43
Figure 18 – Decorative sgraffito motif
on the outer side of the mantle, back.
Figure 19 – Fish-scale pattern on the inner
side of the mantle, back.
All these motifs seem to have been designed freehandedly, and must have been firstly
outlined with a fine sharp stylus of c. 0,1 mm, likely made out of wood or other soft material
not to damage the metal leaf (Martínez 1997:182; Serck-Dewaide et al 2004:144), although
references also refer to the use of silver stylus to scrape off the paint on the required areas
(Nunes 1615:69) (figures 20 and 21).
Figure 20 – Detail of sgraffito with visible
indentation of the outline of the motif. DP c.60x.
Figure 21 – Detail of the overlapping scrape
marks over the vegetal motif. DP c.60x.
Punchwork
Punched adornments were made over silvering and gilding and both the scraped and
raised gesso motifs were complemented with punchwork decoration, enhancing the threedimensional effect of the polychromy through the interplay of light and shadow (Nunes
1615:69; Martínez 1997:179, 182; Serck-Dewaide et al 2004:144). A close survey of the
punch marks allowed to determine the use of simple hemispherical tipped punches with
44
varied sizes (0.6, 0.8, 1, 1.2 and 1.4 mm Ø) (figure 22). The more complex patterns are
created by punch mark juxtaposition to create different shapes, and by slightly dragging the
punch instead of placing it perpendicular to the surface, thus creating oval shapes instead
of circular ones (figure 23).
Figure 22 – Detail of different sized punch
marks. DP c.60x. Image acquired by Tiago Dias.
Figure 23 – Punch marks on gold with
juxtaposition to create a kidney shape. DP
c.60x. Image acquired by Tiago Dias.
Glazing
Figure 24 - 2D elemental mapping by EDS analysis revealing Cu
distribution on the glaze. SEM-EDS analysis by Luis Dias, HERCULES.
Two different kinds of glazes could be found over the sculpture, likely to serve different
purposes. Over the silvering, on the tunic, a translucent green coloured glaze was applied
(figure 16). The double refraction of light on the coloured glaze and metallic surface results
in a high gloss, shimmering appearance that tries to simulate a glossy fabric like silk satin
(Richter 2013a:33; Gómez Espinosa et al. 2004:49; Serck-Dewaide et al 2004:147).
The presence of Cu revealed by EDS elemental mapping indicates that a copper-based
pigment was used (figure 24). Although no conclusive identification could yet be made, the
45
pigment likely used was verdigris, referenced to be commonly employed in the making of
copper green glazes for metallic surfaces (Richter 2013b:69). The absence of observable
copper particles on the glaze layer also points to this hypothesis, since verdigris is known
to dissolve in several mediums such as resins, oils and proteins (Eastaugh et al 2008:289).
The medium employed was not yet identified.
Figure 25 – Detail of a yellow glaze brush
stroke, hem of the mantle. DP c.60x.
Figure 26 - Detail of a floral composition on
the, hem of the mantle.
Another kind of glaze can be found on the mantle following the motifs on the hem (figure
25). Used much more sparingly, it is brush tip painted over the gilding to highlight some of
the shapes of raised gesso and punched compositions, contouring the punched flowers, for
example. Its nature is yet to be determined.
Brush tip painting
The polychromy is finished with fine details brush tip painted. In the fish-scale pattern on
the inside of the mantle, the painting uses a deep darker pink colour to simulate shadows
and a lighter pink colour for highlights, adding a sense of three-dimensionality to the pattern (figures 19 and 29).
On the mantle further embellishment was done on the hem with floral designs of purple
flowers with green foliage fitted between the pastiglia motifs (figures 27 and 28). It was
possible to observe some preparatory drawing for these flowers and leaves made by incision with a stylus over the gold leaf (figure 28). The overlapping of the brush strokes over
scrapped and punched gilding areas also allows to conclude that this was the last process
on the making of this polychromy (figure 29).
46
Figure 27 – Detail of a brush
tip painted flower. DP c.60x.
Figure 28 – Detail of a flower
where preparatory incisions
and brush strokes can be seen.
DP c.60x.
Figure 29 - Detail where
highlight brush strokes cover
scrapped and punched gilt
areas. DP c.60x. Image
Final remarks
This case-study allows to knowledge some of the processes involved in the creation of a
complex polychromy program that is an estofado. The different materials and techniques
used to create the garments of St. John the Evangelist are a paradigmatic example of
Portuguese seventeenth to eighteenth century polychromy.
Few remarks can be made on the pre-existing polychromy. It follows the water-gilding
technique regarding the preparatory layers build-up (gesso and bole) for the gold leaf to
be laid. Once the metal leaf was burnished, the tunic was painted blue and the mantle was
painted red. The presence of paint layers over gilding might indicate the use of techniques
such as sgrafitto (since the most common reason to paint over a gilded area was to make
decorative motifs or patterns, either painted or scraped). However, no definite assumption
can be made without a surface examination to determine the used techniques, prevented
by the re-polychromy that now covers the entire surface.
The visible (re)polychromy, that was the main focus of this case-study, lends itself to
close observation and documentation, revealing a repository of techniques available to the
painter-gilder for the creation of an estofado polychromy. The attention given to detail can be
observed since the preparatory layers, revealing a particular care with regard to the choice
of materials, such as gypsum (gesso fino) employed as only component of the ground, and
a deliberate choice of bole according to the type of metal leaf to be applied on each area.
The use of different metal leafs to represent different textiles is also noteworthy. The gold
leaf is laid as base for a brocade representation, and the silver leaf provides the sheen to
the green glaze to emulate a lustrous satin-like fabric.
Intentionality and planning are also found on the sequenced creation of the decorative
motifs; whether regarding the pastiglia motifs, the construction of which started at the
preparatory layer stage and was complemented through punchwork and brush tip painting,
47
or regarding the preparatory “drawing” with stylus of the motifs to be further scraped off
(sgrafitto) or bush-tip painted.
Although the materials and techniques identified are not uncommon to Portuguese polychromy of the period, the study of the estofado of this St. John de Evangelist’s sculpture
allows to document several of the different skills used to mutually complement each other,
creating a metalanguage that simultaneously embellishes and enriches the sculptor’s work.
References
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Optical Micrsocopy of Historiacal Pigments. Oxford: Elsevier. 2008
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Diocese de Beja. Lisboa: Estar Editora. 1997.
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da documentação dos séculos XVII e XVIII. In Policromia: A Escultura Policromada Religiosa
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2004, pp. 17-22.
GARCÍA, Fernando R. Bartolomé. Aportaciones a Un Glossario de Policromia. In Policromia:
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GÓMEZ-ESPINOSA, Teresa, REBOCHO-CRISTO,José António, MOURA, Carlos, MARTIN
PRADAS,Antonio, LEFFTZ,Michel, CAMPOY NARANJO, María. História E Evolução Da Policromia
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Comparativo Das Técnicas, Alterações E Conservação Em Portugal, Espanha E Bélgica.
Lisboa: Instituto Português de Conservação e Restauro, 2004, pp. 37-54.
HOMEM, Paula Menino. Corrosão Atmosférica da Prata: Monitorização e Perspetivas de
Conservação Preventiva. PhD thesis. Faculdade de Letras da Universidade do Porto, 2013.
LE GAC, Agnes. Les Techniques de Polychromie des «Broderies d’application» et des « bouclés par la trame » - Etude Préliminaire. In Policromia: A Escultura Policromada Religiosa
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2004, pp. 79-94.
MARTÍNEZ, Enriqueta González-Alonso. Tratado Del Dorado, Plateado Y Su Policromía:
Tecnología, Conservación Y Restauración. Ed. Universidad Politécnica Valencia. 1997.
NUNES, Filipe. Arte da Pintura. Symmetria, e Perspectiva. Lisboa: Pedro Crasbeek. 1615.
http://ciarte.no.sapo.pt/recursos/tratados/tratados2.html
RICHTER, Mark. Coloured Glazes on Metal Leaf: Definition and Terminology. In Lüsterfassugen Des Barok Un Rokoko - Coloured Glazes on Metal Leaf from the Baroque and Rococo,
edited by Erwin Emmerling, Michael Kühlenthal, and Mark Richter, München: Studien aus
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Architekturmuseum / Technische Universität München, Fakultät für Architektur, 2013a, pp.
33–37.
Art-Technological Source Research and Scientific Examination: A Comparative Study on
the Thecnique of Coloured Glazes Applied on Metal Leaf. In Lüsterfassugen Des Barok Un
Rokoko - Coloured Glazes on Metal Leaf from the Baroque and Rococo, edited by Erwin
Emmerling, Michael Kühlental, and Mark Richter. München: Studien aus dem Institut für
Baugeschichte; Kunstegeschichte, Kunst und Design; Restaurierung mit Architekturmuseum
/ Technische Universität München, Fakultät für Architektur, 2013b, pp. 39–83.
RODRÍGUEZ, Luis Ángel de la Fuente. Los Metales Plateados Como Policromía (las Corladuras): Análisis-Experimentación Y Restauración. PhD thesis. Universidad del País Vasco =
Euskal Herriko Unibertsitatea, 1999.
SERCK-DEWAIDE, Myriam et al. Les techniques utilisées dan lárt baroque religieux des XVIIe
et XVIIIe siècles au Portugal, en Espagne et en Belgique. In Policromia: A Escultura Policromada Religiosa Dos Séculos XVII E XVIII - Estudo Comparativo Das Técnicas, Alterações E
Conservação Em Portugal, Espanha E Bélgica. Lisboa: Instituto Português de Conservação
e Restauro, 2004, pp. 119-155.
Ackowledgments
The authors would like to acknowledge the support of the Portuguese Foundation for Science and Technology (FCT) through the grants financed by the Ministry of Education and
49
Science attributed to Tiago Dias (SFRH/BD/78214/2011) and Maria José Oliveira (SFRH/
BCGT/51652/2011). We also gratefully acknowledge the support given towards this project
by Museu Nacional de Arte Antiga that facilitated access and information on the studied
sculpture.
Tiago Dias is a conservator-restorer with a Bachelor’s degree in Conservation and Restoration, Furniture and Gilded and Polychromed Altarpieces (talha dourada) specialty, by the
Technology School of Tomar’s Polytechnic Institute (2005). Between 2009 and 2011 he
collaborated in several research and Conservation treatments at José Figueiredo Laboratory –
Directorate-General for Cultural Heritage, funded by a grant from the Portuguese Foundation
for Science and Technology (FCT). He is currently developing a Ph.D. degree in Art History,
Art, Heritage and Conservation, at the School of Arts and Humanities, University of Lisbon,
dedicated to the study on the use of silver leaf in Portuguese sculptures and altarpieces.
Contact:
tiago.dias.mail@gmail.com
Michèle Portela is currently developing her professional activity at José Figueiredo Laboratory – Directorate-General for Cultural Heritage. She holds a Bachelor’s degree in Conservation and Restoration, Mural Painting speciality, by José de Figueiredo Institute (1986), and
attended the Mural Painting Conservation Course by ICCROM in Rome (1992), sponsored by
Calouste Gulbenkian Foundation. She is currently developing a Master’s degree in Museology
and Museography by Faculty of Fine Arts, University of Lisbon.
Contact:
mportela@dgpc.pt
Maria José Oliveira graduated in Technological Physics from the Faculty of Science, University of Lisbon, and collaborates with José de Figueiredo Laboratory – Directorate-General
for Cultural Heritage since 2000, in the analytical laboratory. Her work focuses on the
characterization of inorganic materials of works of art, having specialized in the technique
of micro-X-ray diffraction.
Contact:
moliveira@dgpc.pt
Elsa Murta holds a Bachelor’s degree in Conservation and Restoration of polychrome sculptures by José de Figueiredo Institute (1986), and a Master’s degree in Decorative Arts (talha
dourada) by the Portuguese Catholic University (2011). She is currently developing a Ph.D.
degree in Art History, Art, Heritage and Conservation, at the School of Arts and Humanities, University of Lisbon, studying the influence of Flemish workshops in Portugal between
the 16th and the 17th centuries. Since 1984, she is a conservator-restorer of polychrome
wood sculpture at José Figueiredo Laboratory – Directorate-General for Cultural Heritage.
50
Regular participant in conferences in the field of conservation of polychrome sculpture and
architectural decoration, she as authored 21 written works, individually or in co-authorship
for peer-reviewed publications, books chapters and conference proceedings the field of
conservation and restoration of polychrome sculpture.
Contact:
emurta@dgpc.pt
Cristina Barrocas Dias holds a Ph.D. in Chemistry by the American University, USA and
in Analytical Chemistry by Lisbon University. She is Auxiliary Professor of the Chemistry
Department of Évora University, integrated member of Évora’s Chemistry Center and
Associate Director of HERCULES Laboratory – Cultural Heritage, Study and Safeguard – of
the same University. She coordinates and integrates several scientific investigation projects
regarding the study of historical textiles, archaeological materials, painting and illuminated
manuscripts. Her expertise area focuses on the application of chromatographic analytic
methods to the study of cultural heritage. She has authored several works for peer-reviewed
publications and book chapters.
Contact:
cmbd@uevora.pt
Vítor Serrão holds a Ph.D. by the Coimbra University (1992). He is a Full Professor at the
School of arts and Humanities, Lisbon University and coordinator of the investigation center
ARTis-IHA-FLUL. He presided the History Scientific Committee of the School of Arts and
Humanities, University of Lisbon (2005-07). Coordinating and integrating several research
projects in Art History and Heritage, he specialized on the study of Portuguese painting from
the Renaissance, Mannerism and Baroque, as well as in the fields of Art Theory and Heritage safeguard. He authors numerous books and exhibition catalogs that he has organized,
as well as over two hundred articles in conference’s proceedings, bulletins and specialized
publications, having assiduous collaboration with scientific magazines publishing texts related
to Art History of the 16th to 18th centuries.
Contact:
vit.ser@letras.ulisboa.pt
51
A COMPARATIVE MULTI-ANALYTICAL STUDY
OF THE POLYCHROMY AND GILDING IN TWO
BAROQUE ALTARPIECES OF EVORA, PORTUGAL
Celso Mangucci1 | Irina Crina Anca Sandu2 | Ana Manhita2 | Ana
Margarida Cardoso3 | Luís Dias2
1
PhD Candidate with grant from Fundação para a Ciência e Tecnologia at the University of
Evora, Portugal
2
Hercules Laboratory, Evora University, Portugal
3
PhD Candidate with grant from Fundação para a Ciência e Tecnologia at the University of
Evora, Portugal
Abstract
A dispute among the best five painters-gilders of Evora, for two of the most important
contracts regarding the gilding of the altarpieces, gave rise to an extensive and detailed
documentation on the technique, materials and prices used in 1729. The rivalry between
the master Filipe de Santiago, responsible for the gilding of the whole set of the Church of
Mercy (Igreja da Misericórdia de Évora), and the team led by Manuel da Maia, responsible for
gilding the main altar of the Convent Church of Scala Coeli’s (Igreja do Convento de Scala
Coeli, Cartuxa), forced the commissioners to redraft contracts with unusual rigor since both
did not accept the possibility to be examined by the opponent. Physical-chemical characterization of the gilding and polychrome layers of samples from both altarpieces, performed
within the GILT-Teller project (www.gilt-teller.uevora.pt), led to a comprehensive approach
of the pictorial culture of this period. As it is reported in contracts, the gilded woodcarving
was enriched with flesh-coloured tones, “estofado” and “regraxos”. These techniques were
both used in the Church of Mercy and in the Church of the Convent of Scala Coeli, of the
Carthusian monks of Evora. The documentation and the results of the phsyical-chemical
analyses presented in this paper confirm the existence of a common and poorly differentiated artistic culture between the main workshops of Evora.
Keywords
Portuguese gilded woodcarving, gilding and polychrome techniques, physical-chemical
characterization of polychromy, 18th century.
52
Celso Mangucci | Irina Crina Anca Sandu | Ana Manhita | Ana Margarida Cardoso | Luís Dias
ANÁLISE COMPARATIVA DO DOURAMENTO E POLICROMIA DE DOIS
RETÁBULOS DE ÉVORA, PORTUGAL
Resumo
Uma disputa entre cinco dos melhores pintores douradores de Évora deu origem à realização
de uma extensa documentação sobre a técnica, os materiais e os preços em vigor em Évora,
no ano de 1729. A rivalidade entre o mestre Filipe de Santiago, responsável pelo douramento
do conjunto de talha da Igreja da Misericórdia, e a equipa liderada por Manuel da Maia
que executou o douramento do retábulo da capela-mor da Igreja da Cartuxa, obrigou os
comitentes a redigirem os contratos com um rigor inusual, já que ambos os mestres não
aceitavam a possibilidade de serem examinados pelo oponente. A caracterização físicoquímica do douramento e das camadas de policromia de ambos os altares, realizada no
âmbito do projecto GILT-Teller (www.gilt-teller.uevora.pt), permite-nos uma aproximação à
cultura pictórica do período. Como é reportado nos contratos, o douramento da talha dourada
foi enriquecido com carnações, estofado e “regraxos”. Estas técnicas foram utilizadas de
maneira muito semelhante em ambos os conjunto da Igreja da Misericórdia e no Convento
de Scala Coeli dos monges cartuxos de Évora. Os resultados documentais e analíticos dessa
investigação confirmam a existência de uma cultura comum e pouco diferenciada entre as
principais oficinas de Évora.
Palavras‑chave
Talha dourada em Portugal, materiais e técnicas de douramento, caracterização físico-química
da policromia, século XVIII.
ANÁLISIS COMPARATIVO DEL DORADO Y POLICROMÍA DE DOS ALTARES
DE ÉVORA, PORTUGAL
Resumen
Una disputa entre cinco de los mejores pintores doradores de Évora condujo a la realización
de una amplia documentación sobre la técnica, los materiales y los precios vigentes en
Évora, en el año 1729. La rivalidad entre el maestro Filipe de Santiago, responsable pela
execución del dorado del retablo de la Iglesia de la Misericórdia de Évora, y el equipo dirigido
por Manuel da Maia que realizó el dorado del retablo de la capilla principal de la iglesia de
la Cartuja, obliga los comitentes a redactaren contratos con un rigor inusual, ya que ambos
los maestros no aceptaron la posibilidad de seren examinados por el oponente. La caracterización fisicoquímica del dorado y policromía de los dos altares, que se realizó en el ambito
del proyecto Gilt-Teller (www.gilt-teller.uevora.pt), permite acercarnos a la cultura pictórica
de la época. Como se informó en los contratos, el dorado se ha enriquecido con tonos de
53
carnacion, estofado y „regraxos“. Estas técnicas se utilizan de la misma manera tanto en la
Iglesia de la Misericordia y en la iglesia de Scala Coeli del convento de los monjes cartujos
de Évora. La documentación y los resultados de los análisis químicos presentados en este
documento confirman la existencia de una cultura artística común y poco diferenciada entre
los principales talleres de Évora.
Palabras clave
Retablo dorado en Portugal, materiales y técnicas de dorado, caracterización físico-química
de la policromia, siglo XVIII.
INTRODUCTION
Since the beginning of the sixteenth century, there is a certain social stratification among
the “óleo” (oil) painters and the “têmpera” (distemper) painters. Besides, this social differentiation turns out to be the result of the struggle’s process for the social recognition of
the painters, as evidenced by the lawsuit moved by Lisbon decorative painters (têmpera) in
order to achieve the same benefits granted to the “oil” painters (SERRÃO, 1982). Generally
speaking, this specialization occurs after a common training, taking place due to a professional strategy, and marks the painter’s career in artistic terms.
Another important factor of distinction between the painters is their belonging to the learned
circles of Lisbon, where new artistic ideas are accepted and discussed and where the best
professionals are appreciated and rewarded social and economically. Évora, in the late 15th
century and throughout the 16th century, benefiting from long court stays, was able to sustain
a vibrant and independent art scene. In the seventeenth century, with the establishment
of the court in Lisbon, it becomes even more evident the importance of the archbishops
patronage action, as sponsors throughout all the archbishoprics (SERRÃO, 2015).
After the long and difficult process of restoration of the Portuguese independence, the year
1729 is one of great optimism. The gold and precious stones from Brazil, in constant flux
since the last decades of the seventeenth century, allow the King João V compete with
other European monarchs and develop an artistic patronage in the magnific shape of a
great Maecenas. The double marriage between the monarchs of Spain and Portugal, or as it
will became known, “the exchange of the princesses”, is like a return to political normality,
reinforcing the peace agreements reached in Lisbon, in 1668.
This year (1729) of celebrations imposes many artistic interventions in the way of the
magnificent bridal peregrination that drove the Spanish princess from Caia to Lisbon. It is
due to several royal donations that ended the gilding work of the alterpiece of the Church of
Scala Coeli probably carried out three decades ago (LAMEIRA, 2005) (Figure 1) 1. It is also in
1
“El Rei D. J oão V, que Deus tenha em glória, deu por uma consulta cinco mil cruzados que se cobraram no
Almoxarifado de Évoramonte e no ano de 1729 deu outros cinco mil cruzados na ocasião das passagens das
Princesas para Portugal e Castela que todos se aplicaram às obras da igreja, dourados e pintura e como ainda
54
1729 that are finally completed the gilding works of the Church of Mercy of Évora, covering
with gold the master carver’s work of Francisco da Silva (MANGUCCI, 2008) accomplished
between the years 1710 and 1714 (Figure 2).
Figure 1 – General view of the main altarpiece
of the Church of Scala Coeli, atr. Francisco
Machado, c. 1700.
Figure 2 – General view of the main altarpiece
of the Church of Mercy, Évora.
Francisco da Silva, 1710-1714.
These two decorative campaigns, for most years the bulkiest held in the Archbishopric of
Évora, was a strong incentive for a fierce competition among Évora gilders-painters. On the
one hand, the team led by Manuel da Maia and, on the other, the painter Filipe de Santiago.
The distrust between the two sides, who denied the possibility of a final evaluation of the
work by a master of the city, forced the drafting of quite detailed contracts that give us a
complete information of the various techniques associated with the gilt.
The comparative study of these two campaigns, with the completion of physical and chemical analyses performed on samples taken from polychromy and gilding, contributed to the
knowledge of a variety of plastic resources used by gilders-painters, particularly in the
context of Évora’s artistic world in the eighteenth century. It also allows us to know the
social life of these regional painters who established client networks with the major religious
institutions in the city.
faltava o dourado dos retábulos, o Nosso Padre Prior fez súplica ao mesmo Senhor D. João V, que logo segundo
a sua costumada piedade e grandeza deu outros dois mil cruzados com que se acabou o douramento“ [Lameira,
2014].
55
HISTORICAL BACKGROUND
The study of gilded carved wood in Évora offers a good opportunity to understand the
development of the decorative arts in the regional context. Unlike the painting of tiles in
Lisbon, the execution of gilded woodcarving requires the establishment of regional workshops, and Évora was a radiating centre for the Alentejo, in the seventeenth and eighteenth
centuries. On the other hand, there is still a “dependence” from Lisbon, with the renewal of
generations and the start of new art ideas, made by the out coming of new masters from
the capital (MANGUCCI, 2010).
In Évora, there are examples of recognized painters who, attracted by a good economic
return, perform or supervised the gilt of altarpieces. This is the case of painter Francisco
Nunes Varela (1621-1699) responsible for the gilding of the chapel of Our Lady of the
Rosary’s altarpiece, in the church of the extinct Convent of St. Domingos, for the sum of
250 000 reis, in 1667 (BORGES, 2014).
In this particular case of Filipe de Santiago and Manuel da Maia, we are dealing with regional
artists with a weak individual recognition and their pictorial productions extend from a wide
range of contributions of small interventions of restoration, conducting pictorial campaigns
on fresco and oil paintings. We could say that they are considered painters in the most
technical mean of the word.
The painter Filipe de Santiago, over which we have more data, was the author of the fresco
painting of the church of Safara, in Moura (SERRÃO e CAETANO, 1999) in 1722. The painter has
established relationships with various Churches of Mercy in Alentejo, and in spite of constant
complaints, he accumulated enough money to send two daughters to the village’s convent.
Manuel da Maia was “brother” of the Mercy of Évora, having participated in the important
Lord’s burial processions, dressed like a prophet. He was responsible for carrying out several
interventions of sculptures and small restorations. In 1702, with other painters, he gilded
the altarpiece of the Dead Christ Chapel in the church of the brotherhood.
The agreement2 for the gilding work, which was signed on July 24, 1728, between the Mercy
and Manuel da Maia, Bernardo Luis, Francisco Ferreira and José Correia, lists a number of
technical recommendations related to the intended pictorial results, making it possible that
behind the writing of the contract there is a strong artistic culture, which was unusual:
“primeyramente se obri/garão a dourar toda a obra de madeyra que es/tiver no frontespicio
da igreja com o ouro/ mais corado que ouver e alguns vãos que tiver o en/talhado porque
paresse em que est a/centado os pintarão de jalde para que a pa/rede com a brancura da
cal não deslus/tre o dourado. As figuras, serafins, es/cultura e a mais obra que estofarem
sera/ tudo sobre ouro e não sobre prata ou tin/ta alguma, e as encarnações serão de poli/
mento, e não de pincel toda a obra se/ aparelhará com nove mãos de aparelho/ em sua
Arquivo Distrital de Évora. Santa Casa da Misericórdia de Évora, n.º 27. Livro de Lembranças que começou em
1728, fl. 19 v.º-20.
2
56
conta, que será de retalho de luva/ fino e os estofados das figuras e azas dos/ serafins
se estofarão com as cores mais/ finas e os regraxos desta obra de verdes/ estilhados, e
lacras muito finas e subidas que o ouro sera todo burnido, e aparessen/do a essa meza que
se lhe fação alguns/ foscos e serão feytos sobre ouro, o que ficara/ ao arbitrio da mesma
determinar se há de/ levar a dita obra os taes foscos ou se ha de ser/ do de burnido....”3
For its part, the agreement4 between Filipe de Santiago and the carthusian fathers, concluded
on March 31, 1729, was concerned primarily in defining the preparation of layers for the
gilding, this preparation composed of three layers: the first with coarse plaster, the second
with fine plaster and the last the bole in a total of eleven “hands” superimposed:
“elle dito Philipe de São Thiago será obrigado a trazer por sua conta/ na dita obra do dourado
do dito retabolo tribuna da dita cappela mayor da dita igreja da/Cartuxa seis pessoas efetivamente cada dia the final concluzão da dita obra; aparelhando/ a mesma com boa e san
consciencia para o que elle dito Philipe de São Thiago fará dar/ por sua conta onze mãos de
aparelho das quais serão três mãos de jesso grosso quatro mãos de/ jesso mate e quatro
mãos de bôllo; E outrossim que elles ditos Reverendos Relligiosos seram obrigados a pagar
e satisfazer a elle dito Philippe de São Thiago a importancia das encarnaçõis/ e estofados e
mais pinturas que forem necessarias e se fizerem no dito retabolo e tribuna da dita/ capella
maior da dita igreja; Como também seram obrigados elles ditos Reverendos Relligiosos/ a
pagar e satisfazer a elle dito Philipe de São Thiago dois mil e novesentos e quarenta reis
pello/ trabalho de suas mãos por cada hum milheiro de ouro, que lhe dourar”5.
In both cases, these first contracts had no effect and the masters were replaced. Therefore,
Filipe de Santiago carried out the gilding of the altarpiece of the Mercy of Évora, and Manuel
Maia the gilding of the convent of the Charterhouse.
Given the chronological proximity, the belonging to the same local cultural context, the
uniqueness of the cross-drafting of the contracts, and the availability of raw materials, we
might expect not to find any substantial differences between the decorative campaigns of
“..first of all, they will gilt all the woodcarved that is in the frontispiece of the church with the most coloured gold
and there are some gaps in the wood-carved that seems would be prepared with “jalde” because the whiteness
of the lime not tarnish the gold. The figures, seraphs, sculpture and more work that will be “estofado” is all over
gold and not silver or paint, and the flesh tones will be polishing, not by brush. The entire work will be prepared
with nine “hands“in your account, which will be polished with fine gloves and the upholstery of figures and
wings of the seraphs will be “estofado“ with the finest colours and „regraxos“. This work of green “estilhados”
and lacquers very thin and subtle and the gold will be all burnished, and if the direction of the Mercy will make
some dull, will be made over gold, which had been the arbitrariness of it determine whether to take the work
dull or if there is to be burnished...”
4
Arquivo Distrital de Évora. Cartórios Notariais, Livro 1261, fls. 7 e 8.
5
“Him, Filipe de São Thiago will be required to bring with,/ for the work of the gilt of the altarpiece of the church/
of Chartreuse, six people effectively every day until the end of the work; preparing/ the woodcarving with good
and sane conscience for what he, Filipe de São Thiago will give/ at your own, eleven “hands”, and it will be
three hands of thick plaster, four hands,/ “mate” plaster and four hands of Bole; and likewise said that they, the
fathers will be required to pay and satisfy him, Filipe de São Thiago, the importance of carnation/ and upholstery
and more paintings that are necessary, and if done on the altarpiece of that church; as well they will required
to/ pay and satisfy Filipe de São Thiago, with two thousand and nine hundred and forty “reis” for/ his work for
every thousand of sheet gold, that was gilt...”
3
57
the Charterhouse and the Mercy of Evora. Few samples were taken from the two altarpieces
to prove this statement.
Of particular interest is the term used to describe the “regracho” technique. As shown by
the Tratado of Filipe Nunes, the most widely spread book on painting (1615), the technique
must be used for a colour gradation over gilt (NUNES, 1982)6.
ANALYTICAL PROTOCOL
The analytical protocol on several samples taken from both altarpieces aimed to the characterization of the layers in the polychrome structure of the gilding and paint over the carved
wood decoration, for a comparative study of materials and techniques.
Sampling
The following samples were taken: 9 samples from the main altarpiece of the church of Mercy
and other 9 from the altarpiece in the convent of Cartuxa. The gilding areas are represented
in the samples: PT-AM-IMEv_1 to 3, 6 (restoration area) and 9 (throne area), PT-AM-CCxEv_1
to 4, 6 to 8 and 10. The polychromy samples have different colors: red (PT-AM-IMEv_3
and 4; PT-AM-CCxEv_4, 6 and 10); green (PT-AM-IMEv_5 and 7, PT-AM-CCxEv_1), blue
(PT-AM-CCxEv_7) and white-pink (PT-AM-IMEv_8 and PT-AM-CCxEv_5 - flesh tones). The
samples, after being labelled with the acronym established for each altarpiece, were stored
and are fully documented in the PC database of the Gilt-teller project [SANDU, 2013].
Figure 3 shows some examples of sampling areas and the taken samples.
Sample PT-AM-CCxEv_l, taken from the medallion from the support
of the first column of the left side (green polychromy).
“O que quiserdes regraxar fareis primeiro com branco & preto, mas os altos sejam bem brancos, & os pretos
bem pretos. Depois de enxuto e seco tomay o Verdete muito bem peneirado...”.
6
58
Sample PT-AM-CCxEv_l, taken from the mascara head of the support
of the first column of the left side (green polychromy).
Sample PT-AM-IMEv_ 4, taken from the red polychromy
of the flower from the pilaster on the left side of altarpiece.
Sample PT-AM-IMEv_6, taken from the restoration area on the column
from the left side of the altarpiece.
59
Sample PT-AM-IMEv_8, taken from the foot carnation (behind)
of the canatid angel, left side column.
Figure 3 – Selection of sampling areas and samples for both altarpieces.
Experimental conditions
The analytical protocol proposed within the Gilt-Teller project [SANDU, 2013] made use of
several techniques aimed to characterize the gilding layers and polychromy and to identify
the techniques applied by the gilderers/painters in the attempt to establish similarities and
differences in the materials and techniques of the two altarpieces. Thus optical microscopy
(OM, visible light and UV) was used on cross-sections of samples together with scanning
electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDS), and
Infrared Fourier Transformed micro-spectroscopy (microFTIR). Liquid chromatography
with diode array detector coupled with mass spectrometry (LC/DAD/MS) and pyrolysis
gas-chromatography coupled with mass spectrometry (Py-GC/MS) were also performed on
micro-fragments.
Cross-sections were obtained using an Epofix embedding resin with hardener, dry polished
with successively finer grades of Micro-mesh abrasive cloths (500, 800, 1200, 2400 and 4000
mesh). A felt was used for the final polishing. For the better optical microscopy observation
a drop of glycerol was applied and then a glass lid over the surface of the cross-section.
Optical microscopy images were taken from the surfaces and cross-sections at different
magnifications (from 100× to 500×) using an LEICA DM2500M binocular microscope, coupled
to a digital camera. Visual light observations (illumination position for dark field observation,
position 1) were performed in reflection geometry and for the fluorescence observation an
UV block filters was used (position 3).
Scanning electron microscopy was performed with a HITACHI S3700N interfaced with
a QUANTAX EDS microanalysis system, equipped with a BRUKER AXS 5010XFlash® Silicon
Drift Detector (129 eV Spectral Resolution at FWHM/Mn Kα). The operating conditions for
EDS analysis were as follows: 20 kV accelerating voltage and 10-12 mm working distance.
60
During the analysis backscattering images, point analysis and chemical mapping data were
obtained on cross-sections that were previously coated with graphite.
For the Infrared spectroscopic analysis on 3 samples a Bruker Tensor 27 model spectrometer was used, in the MIR region of infrared. The spectrometer was coupled to a Hyperion
3000 microscope controlled with a software OPUS 7.2, Copyright© Bruker Optik GmbH
2012, with a MCT detector (Mercury Cadmium Telluride ) which allows acquisition of spectra
on different points on a sample. The samples were analyzed in transmission mode using
a 15x objective and a compression diamond microcell EX’Press 1.6 mm, STJ-0169. The IR
spectra were taken within 4000-600 cm-1, with 64 scans and a spectral resolution of 4 cm-1.
Only 2 samples (PT-AM-IMEv_3 and PT-AM-CCxEv_10) were analyzed by LC/DAD/MS
and Py-GC/MS to identify the red lake and surface coating (varnish). Each sample was
separated in 2, observed under stereomicroscope (each weighing less than 200 μg), one
microfragment for each analysis.
The lake extraction was done according the methodology published by Wouters et al (WOUTERS, 2011).Each sample was placed in a centrifuge vials to which 200 µL of a solution
of methanol/acetone/water/hydrofluoric acid (30:30:40:1; v/v/v/v). The extraction took
place during 4 hours, at room temperature. Then the solvent for extraction was completely
removed by liofilization and the samples were diluted again in 50 μL of methanol/water
(1:1, v/v), centrifuged at 8000 rpm for 10 minutes, and then the supernatant was removed
and placed into the LC/DAD/MS system.
The samples of surface coatings were put into a stainless steel Eco-cup and derivatized with
10 μL of tetramethylammonium hydroxide (TMAH, 25% in methanol).
The analyses were carried out in a LCQ Fleet Thermo Finnigan mass spectrometer equipped
with an electro-spray ionization source and an ion-trap mass analyzer. The MS analysis
conditions were: capillary temperature of 300°C, source voltage of 5.0 kV, source current
of 100.0 µA and capillary voltage of -7.0 V in negative mode. The analytes were detected in
full MS mode (100-800 m/z) and two segments were used: 10.0 V of source fragmentation
from 0-12 minutes and 30.0 V of source fragmentation from 12-30 minutes.
The mass spectrometer was coupled to an HPLC system with autosampler (Surveyor Thermo
Finningan) and diode array detector (DAD). The analytic column was a reversed phase Zorbax
Eclipse XDB C18 (Narrow Bore, particle size 3.5 μm, 150 mm x 2.1 mm). Column temperature was set at 30 °C and tray temperature was set at 24 °C. Chromatographic separation
occurred at a mobile phase flow of 0.2 mL min-1, and 20 μl of sample were injected. The
mobile phase was composed by an aqueous solution of 0.1 % formic acid (v/v) (solvent
A), and acetonitrile (solvent B), using the following elution programme: 0-63 % of solvent
B from 0-14 minutes, 63-90% of solvent B from 14-25 minutes and 90% of solvent B from
25-30 minutes. The DAD detector was programmed to collect spectra between 200 and
800 nm. For the analysis by Py-GC/MS a system with a Frontier Lab PY-3030D double shot
61
pyrolizer was used. The interface was maintained at a temperature of 280 °C. The pyrolizer
was coupled to a Shimadzu GC2010 gas chromatographer, also coupled to a Shimadzu
GCMS-QP2010 Plus mass spectrometer. A capillary column Phenomenex Zebron-ZB-5HT
(15 m length, 0.25 mm internal diameter, 0.10 μm film thickness) was used for separation,
with helium as carrier gas, adjusted to a flow of 1.5 mL min-1. The splitless injector operated
at a temperature of 250 °C. GC temperature programme was the following: 40°C during
5 minutes, ramp until 300 °C at 5 °C min-1, and then an isothermal period of 3 minutes.
Source temperature was placed at 240 °C and the interface temperature was maintained
at 280 °C. The mass spectrometer was programmed to acquire data between 40 and 850
m/z. The samples, previously derivatized in a 50 μL Eco-cup capsule, were placed in the
double-shot pyrolizer using an Eco-stick. The capsule was placed in the pyrolysis interface,
followed by a 2-minute helium purge. Samples were pyrolyzed using a single-shot method
at 500°C during 12 seconds.
RESULTS AND DISCUSSION
The OM and SEM microscopic observation reveal a similar stratigraphic pattern and sequence
of layers. Over the wooden support (visible in samples 1, 6 and 8 from PT-AM-IMEv altarpiece
and in sample PT-AM-CcxEv_5) a thick white ground (250-300 µm for the first altarpiece
and 200-500 µm for the second one) was applied and then the red bole layers of 50-80 µm
for the PT-AM-IMEv and 40-60 µm for PT-AM-CcxEv. The grounds for both cases are made
of the traditional sequence of gesso grosso and gesso fino (gesso mate), as figure 4 shows.
Gold leaf was applied on the top of the bole and burnished and in few cases covered with
a varnish layer (samples 6 and 10 from Carthusian altarpiece). The polychromy presents
different colors according the sampling positions (figure 5). In many cases the paint was
applied over gilding. A thick dark layer (ca 100-120 µm) with bluish fluorescence under
OM-UV for samples PT-AM-IMEv_3, 6 and 9 can be observed (figure 5).
62
A
B
Figure 4 – Comparative imaging under OM and SEM for: A) Gesso grosso and gesso fino in two
samples from the two altarpieces; B) flesh tones stratigraphy in two samples.
63
Figure 5 – Samples 3 and 6 from the altarpiece in the church of Mercy,
observed under OM (vis and UV) and SEM.
Figure 6 shows the comparison in the sequence of layers and elemental mapping by SEMEDS between the samples taken from flesh tones. The presence of elements such as Pb,
Hg, Fe, Al, Si suggest the use of traditional pigments: lead white, vermillion and red ocher
with particles of clay minerals, which could come from lower (bole and gesso) or upper
(depositions from atmosphere) layers.
Figure 6 – SEM-EDS elemental mapping on cross-section of two samples from flesh.
64
From a compositional point of view the gesso grounds are made of calcium compounds
(mainly sulfates) as Ca, S, and O was detected by SEM-EDS, with inclusions of Fe, Si, Al
(clay minerals) and Sr. The detection of Sr indicate the presence of celestite, which was
also detected in gesso grounds from other Portuguese altarpieces (BARATA et al, 2012,
COROADO, 2013, e SANDU, 2014). The literature assesses the possibility that this type
of gesso could be imported because the Portuguese geological outcrops are small when
compared with other countries as Spain, France or Morroco (Costa, 1986) although the
contemporary treatises speak of the use of national gesso coming from Obidos (Leiria) and
Soure (Coimbra) (Monteiro & Cruz, 2010).
The red bole layers are made of ochers and aluminium silicates (Fe, Al, Si). The leaf, an
alloy of Au, Ag and Cu or only Au /Ag (sample PT-AM-CCxEv_8) has 23 karats and few
micrometers thickness for both altarpieces (figure d), this composition being in agreement
with other findings reported in the literature for Baroque altarpieces in Portugal [SANDU,
2013 e 2015]. Leafing with different materials than gold leaf was identified in the case of
PT-AM-IMEv, using silver leaf (silvering) in sample 6 and alloy of Cu and Zn for sample 9.
As stated above, the work contract specifies the total number of layers for the gilded areas
(11 hands between gesso and bole layers) but from the OM and SEM images is very difficult
to assess this, although a distinction between layers is possible when speaking o gesso
grosso (coarser grains) and gesso fino. Nevertheless the total thickness of layers (variable
according the sample, between 200 and 600 µm) and different colors indicates the overlapping of different layers and materials according the traditional recipes.
The main pigments identified by SEM-EDS and microFTIR are: lead white with inclusions
of gesso and silicates (Ca, S, Si) in sample PT-AM-IMEv_4 and with red grains of vermillion
(Hg) in sample PT-AM-IMEv_8 (flesh tones) and sample PT-AM-CcxEv_5; green pigment
(probably a copper resinate) in sample 1 (green) and 7 (blue) from Cartuxa altarpiece,
similar to the one from sample 7 in the church of Mercy; vermillion (HgS) in red samples
(PT-AM-CcxEv_4 and 6).
LC/DAD/MS technique allowed to identify the red color organic layer from the surface
as cochineal lake of possible Mexican provenance in both cases (figure 8). Beeswax was
identified as coating (figure 9) in sample 6 and 10 from the Cartuxa altarpiece, having the
same composition as sample 3 from the church of Mercy altarpiece. The presence of copper
carboxylates and of a fatty material (oil?) was detected in the microFTIR spectra of green
samples (figure 10) in both altarpieces. The carboxylates are the product of the interaction
between a metal ion (in this case Cu2+ of the green pigment) and an acid from an organic
compound (probably the oil or even the wax from protective coatings).
65
Figure 7 – Gold leaf composition detected by SEM-EDS
analysis for two samples from the two altarpieces.
Figure 8 – LC/DAD chromatographic profile of sample PT-AM-CCxEv_10
and data obtained from LC/DAD/MS for both red color samples.
66
Figure 9 – Data from Py-GC/MS for sample PT-AM-CCxEv_10.
Figure 10 – Characterization of sample 1 from the altarpiece
in Cartuxa convent by OM, SEM-EDS and microFTIR.
CONCLUSION
Following the results obtained from the analytical protocol, the stratigraphic structure and
the constituent materials in the gilded and polychrome layers of the two altarpieces seem
quite similar.
67
The gesso grounds have the same composition, including the presence of Sr (as marker for
celestite), and technique (gesso fino over layers of coarser gesso grosso).
The bole is made with iron oxides and aluminium silicates (clay minerals) and has a reddish
colour. We were not able to identify the yellow bole (“jalde”) proposed in the first contract
of the Church of Mercy, but the thickness and compositional pattern of the gesso-bolelayers
are confirming the recommendations from the work contracts (11 hands in total).
The leaf is an alloy of Au, Ag and Cu of 23 karats (good quality/purity) with few exceptions
in the case of the altarpiece from the church of Mercy where interventions were made using
silver leaf and Cu/Zn leaf.
The polychromy is made of pink, red, green and blue hues. Main colouring materials identified
are: lead white for white and pink areas, vermillion, cochineal lake and copper resinate (?).
The organic materials identified are: oil as binder for the painted areas “regraxos” (identified
for green and red samples), and wax as protective layer7.
The polychromy of the altarpieces seems to be made in an oil paint technique with organic
protective (wax), while the gilding is a water-based technique using leaf of 23 karats and
in some cases (for the altarpiece of the church of Mercy) silver or Cu/Zn leaf.
In this case study, the similar results for composition and application techniques of the ground,
gilding and painting layers confirm that the belonging to a relatively small community, and the
participation in a broad partnership for the execution of large works contributed to the dissemination of relatively homogeneous techniques and artistic practices, allowing the commissioners,
with relative ease, to replace the gilders without changing the expected final results.
The dispute between the two masters, Manuel da Maia e Filipe de Santiago, forced both
commissioners, the brothers of Mercy and the Carthusian fathers, to write the contracts
with very careful details, describing all the process of gilding and the techniques of painting
over gold.
References
BARATA Carolina, CRUZ António João, ROCHA Fernando, Sobre os materiais utilizados
na talha da época barroca do noroeste de Portugal – primeiros resultados, in -Actas do I
Encontro Luso-Brasileiro de Conservação e Restauro, Porto, CITAR, pp.40-50, 2012. [Em
Linha] disponível em: http://citar.artes.porto.ucp.pt/sites/default/files/files/artes/CITAR/
Edicoes/actas-I-encontro-luso-brasileiro-conservacao-restauro-2011.pdf
BORGES Artur, “As andanças de um retábulo eborense”, Catálogo da exposição Documentos
para a história da Talha dourada e azulejo em Évora, coordenada por Celso Mangucci.
Both sets underwent conservation and restoration works in recent decades. In 2005, Tacula company, led by
architect João Sarrazola Martins, presented an oral communication at the Eugénio de Almeida Forum about the
intervention of conservation and restoration carried out on the gilded altarpieces of the church of the convent
of Scala Coeli Évora.
7
68
Évora: Arquivo Distrital de Évora, 2014. [Em Linha] disponível em: http://adevr.dglab.gov.
pt/wp-content/uploads/sites/4/2014/11/link.pdf
COROADO João, ANTUNES Vanessa, SERRAO Victor, OLIVEIRA Maria José, DIAS Luís,
CANDEIAS António, MIRÂO José, SERUYA Ana Isabel, Presença de Celestite em retábulos
Portugueses, V. Serrão, V. Antunes e A.I. Seruya (eds.), As preparações na Pintura Portuguesa, seculos XV and XVI, Faculdade de Letras da Universidade de Lisboa, 28-29 Junho
2013, Museu Nacional de Arte Antiga, pp. 75-83, 2013
COSTA J.R.G, O Gesso em Portugal, Estudos, Notas e Trabalhos do Serviço de Fomento
Mineiro, vol. 28, pp. 93-117, 1986
LAMEIRA Francisco, “O retábulo da capela-mor da Igreja do Mosteiro da Cartuxa de Évora
(projecto de José Benito de Churriguera?)”, Catálogo da exposição Documentos para a
história da Talha dourada e azulejo em Évora, coordenada por Celso Mangucci. Évora: Arquivo
Distrital de Évora, 2014.[Em Linha] Disponível em http://adevr.dglab.gov.pt/wp-content/
uploads/sites/4/2014/11/link.pdf
LAMEIRA Francisco, O Retábulo em Portugal, das origens ao declínio, Promontoria Monográfica
Historia da Arte, n.º1, Departamento de Historia, Arqueologia e Património a Universidade
de Algarve, Faro, 2005
MANGUCCI Celso, A talha mais moderna. O percurso de Manuel e Sebastião Abreu do Ó
em Évora in Cenáculo Boletim on-line do Museu de Évora, nº 4, Outubro de 2010.[Em
Linha]. Disponível em: http://museudevora.imc-ip.pt/Data/Documents/Cenaculo%204/
B4AbreudoO2010.pdf
MANGUCCI Celso, “Francisco da Silva, António de Oliveira Bernardes e Francisco Lopes
Mendes na Igreja da Misericórdia em Évora in Cenáculo Boletim on-line do Museu de Évora,
nº 3, Setembro de 2008.[Em Linha] Disponível em:http://museudevora.imc-ip.pt/Data/
Documents/Cenaculo3/B3SilvaBernardesMendes2008final.pdf
MONTEIRO Patrícia, CRUZ António João, Breve tratado de Iluminação composto por um
religioso da Ordem de Cristo. In L.U. Afonso (ed.), The materials of the image. As Matérias
da Imagem. Lisboa: Cátedra de Estudos Safarditas “Alberto Beniveste” da Universidade de
Lisboa, pp.237-286, 2010
NUNES Filipe, Arte da Pintura Symmetria, e perspectiva com estudo introdutório de Leontina
Ventura. Porto: Editorial Paisagem, 1982
SERRÃO Vítor, O Maneirismo e o Estatuto Social dos Pintores Portugueses. Lisboa: IN/CM, 1982
SERRÃO Vítor, Arte, Religião e Imagens em Évora no tempo do Arcebispo D. Teotónio de
Bragança, 1578-1602. Vila Viçosa: Fundação Casa de Bragança
SERRÃO Victor, CAETANO Joaquim, A Pintura em Moura nos Séculos XVI, XVII e XVIII.
Moura: Câmara Municipal de Moura, 1999
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SANDU Irina Crina Anca, MURTA Elsa, FERREIRA Silvia, PEREIRA Manuel, CANDEIAS António,
MIRÃO José, MIGUEL Catarina Pereira, PABA Francesca, More than gold – an interdisciplinary, complementary study of gilding materials and techniques in Baroque altarpieces from
Portugal, in ECR-Estudos de Conservação e Restauro, no 6, CITAR, Porto, 2014, pp.13-3.
[Em Linha] http://revistas.rcaap.pt/ecr/article/view/7522
SANDU Irina Crina Anca, PABA Francesca, MURTA Elsa, COSTA PEREIRA Manuel, RIBEIRO
Conceição, Travelling Beneath the Gold Surface – Part I: study and characterization of
laboratory reconstructions of Portuguese seventeenth and eighteenth centuries ground and
bole layers, e-conservation journal, issue 2, 2014, 43-63
SANDU Irina Crina Anca, GILT-Teller: An interdisciplinary multiscale study of gilding techniques and materials in Portugal, 1500-1800, in Actas das VIII Jornadas de Arte e Ciência
- Conservação e Restauro de Artes Decorativas de Aplicação Arquitectónica,29 Setembro
de 2012, CITAR, Porto, 2013, pp.127-142. [Em Linha] Disponível em: https://artes.porto.
ucp.pt/sites/default/files/files/artes/CITAR/VIII-Jornadas-Arte-Cieencia_compressed.pdf
SANDU Irina Crina Anca, MURTA Elsa, NEVES Eva Raquel, PEREIRA Manuel, SANDU Andrei
Victor, KUCKOVA Stepanka, MAURICIO Antonio, A comparative, multi-scale and interdisciplinary study of gilding techniques and materials in two Portuguese Baroque “talha dourada”
complexes, in ECR-Estudos de Conservação e Restauro, no 4, CITAR, Porto, 2013, pp.
47-71, doi: 10.7559/ecr.4.3080. [Em Linha] Disponível em: http://revistas.rcaap.pt/ecr/
article/view/3080
WOUTERS Jan, GRZYWACZ Cecily, CLARO Ana, Studies in Conservation, 56, pp. 231-249, 2011
Websites:
www.gilt-teller.uevora.pt
Aknowledgements
This work has been supported by Fundação para a Ciência e a Tecnologia through the grant
PTDC/EAT-EAT/116700/2010. Authors are also grateful for the support of IMAGOS – Innovative Methodologies in Archaeology, Archaeometry and Geophysics – Optimizing Strategies
nX APOLLO - Archaeological and Physical On-site Laboratory – Lifting Outputs, n. ALENT07-0224-FEDER-001760, funded by INALENTEJO programme through FEDER Project.
Authors CV
Celso Mangucci is an expert in tiles and gilded wood carved history in Portugal, with special
focus on the seventeenth and eighteenth centuries. He has published several papers, was
curator of exhibitions and is the author of three monographs on this subject. He is currently
70
benefiting from a FCT scholarship (SFRH/BD/101946/2014) to complete the PhD at the
University of Évora.
Contact:
cmangucci@gmail.com
Irina Crina Anca Sandu is a Researcher - Conservation Scientist with 18 years of experience (12 of post-doctoral activity, PhD in chemistry) in the field of investigation, diagnosis
and authentication of cultural heritage. She is author or co-author of 12 monographs, 2
book-chapters, more than 100 papers in peer-reviewed journals and conference proceedings
(corresponding author for 20 peer-reviewed papers in ISI indexed journals with H factor 15
and more than 520 citations).
Since the period of her university studies she has been involved in research projects and
international collaborations dealing with movable and immovable heritage. She is the coordinator (PI) of the project Gilt-Teller: um estudo interdisciplinar multi-escala das técnicas
e dos materiais de douramento em Portugal, 1500-1800” (PTDC/EAT-EAT/116700/2010)
funded by FCT in Portugal.
Contact:
irinasandu@uevora.pt
Ana Manhita holds a degree and a PhD in Chemistry. She is a Post-Doc Researcher at
HERCULES Laboratory, and is specialized in advanced chromatographic techniques, with
special focus on the analysis of organic materials in cultural heritage objects.
Contact:
anaccm@uevora.pt
Ana Margarida Cardoso has a master’s degree in Materials Engineering.
She held an internship at the Institute of Museums and Conservation in the Laboratory
José de Figueiredo (LJF) under the Internship Program in Public Administration. Since then
has collaborated on several projects funded by FCT in Portugal, at the LJF and HERCULES
Laboratory, with special focus on materials characterization through vibrational spectroscopy.
She is with a research scholarship in art history (University of Évora, Portugal), PhD HERITAS - Heritage Studies (HERITAS/PD-FCT/BIC/2014).
Contact:
anamacardoso@yahoo.com
Luis Dias is an expert in Scanning Electron Microscopy technique, and works with heritage
materials since 2011. He has a master degree in Environmental Chemical Analisys and is
co-author of 3 book chapters and 12 papers.
Contact: luisdias@uevora.pt
71
THE BEHAVIOUR OF SCHLAGMETAL APPLIED
ON DIFFERENT TYPES OF GILDING SIZES
Ana-Maria Budu1 | Ioana Hutanu1 | Viorica Vasilache2 | Ion Sandu2
1
Al. I. Cuza University, Faculty of Geography and Geology, Iasi, Romania
2
Al. I. Cuza” University/ARHEOINVEST Interdisciplinary Platform/Iasi, Romania
O COMPORTAMENTO DO SHLAGMETAL APLICADO A DIFERENTES TIPOS DE
MORDENTES
Resumo
O schlagmetal (ouro holandês), obtido a partir de uma liga de cobre e zinco é uma alternativa barata à folha de ouro, mas sua cor muda devido a oxidações que aparecem como
resultado de manipulações incorrectas ou de exposição a fatores ambientais (temperatura,
umidade). Este artigo apresenta a influência da película de proteção à base de goma-laca
e de dois aglutinantes (à base de óleo e água) no schlagmetal. aplicado sobre um suporte
de madeira com preparação de gesso. Para avaliar o comportamento da folha de metal nas
estruturas apresentadas no presente estudo, as amostras foram expostas a envelhecimento
artificial e as alterações registadas foram analisadas por microscopia óptica (MO), SEM-EDX
e colorimetria em sistema CIE L*a*b*.
Palavras‑chave
Schlagmetal, mordente, envelhecimento artificial, OM, SEM-EDX, Colorimetria em sistema
CIE L*a*b*.
EL COMPORTAMIENTO DEL SCHLAGMETAL APLICADO A DISTINTOS TIPOS
DE MORDIENTES.
Resumen
El schlagmetal (Oro holandés) , obtenido a partir de una aleación de cobre y zinc es una
alternativa barata a la hoja de oro , pero su color cambia debido a la oxidación que aparece
a consecuencia de una manipulación incorrecta o de la exposición a factores ambientales
(temperatura, humedad). En este artículo se estudia la influencia de la película de protección
a base de goma laca y de dos aglutinantes (a base de agua y aceite) en el schlagmetal,
aplicada sobre un soporte de madera con preparación de yeso.
Para evaluar el comportamiento de la hoja metálica en las estructuras que se presentan
en este estudio, se expusieron las muestras a un envejecimiento artificial y los cambios
72
THE BEHAVIOUR OF SCHLAGMETAL APPLIED ON DIFFERENT TYPES OF GILDING SIZES
Ana-Maria Budu | Ioana Hutanu | Viorica Vasilache | Ion Sandu
registrados se analizaron por microscopía óptica (MO), SEM-EDX, por y colorimetría en
sistema CIE L*a*b*.
Palabras clave
Schlagmetal, mordiente, envejecimiento artificial, MO, MEV-EDX, colorimetría en sistema
CIE L*a*b*.
Abstract
The schlagmetal (Dutch Gold), obtained from an alloy of copper and zinc is a cheap alternative
for gold leaf, but its colour changes due to oxidations which appear as a result of incorrect
manipulations or of exposure to environmental factors (temperature, humidity). This paper
presents the influence of shellac based protection film and of two mixtion binders (water
and oil based size) on the schlagmetal applied on a gessoed wooden support. To evaluate
the behaviour of the metal sheet in the structures presented in this study, the samples were
exposed to artificial ageing, and the occurred changes were analyzed by optical microscopy
(OM), SEM-EDX and colorimetry in CIE L*a*b* system.
Keywords
Schlagmetal, gilding size, artificial aging, OM, SEM-EDX, colorimetry CIE L*a*b*.
Introduction
Schlagmetal or Dutch Gold has reduced considerably the price of gilding technique. This 19th
century innovation is based on a copper and zinc alloy that has similar properties to gold
leaf. Schlagmetal is an advantage for artists because is easier to manipulate, as is thicker
than the gold leaf. Nowadays is frequently used to decorate new art objects and redecorate
old ones: altars, sculptures, furniture ornaments, cassettes, frames, and easel and mural
paintings (Jenkins, 2007; Sandu et al, 2011:1171-1181).
Among the gilding techniques, the gilding with oil based sizes was taken and adapted to
schlagmetal (Bigelow and Hutchins, 1991; Guerra, 2008:317-324; Oddy, 1981:75-79; Sandu
et al, 2010:47-63; Sandu et al, 2011:1171-1181).Thus, one of the modern materials used
in schlagmetal gilding was „mixtion” (mordant gilding size), a viscous lake that contains
linseed oil, litharge (PbO) and turpentine, and can be used on different supports like stone,
metal, textiles or wood (Sardela, 2008:86).
There is a large range of gilding sizes on the market nowadays, based on linseed oil, natural
resins or polymers (Andreotti et al, 2014:300-307; Budu et al, 2015:1212-1216; Hutanu
et al, 2015:895-900; de la Torre-Lopez et al, 2014:1052-1058; Rydlova and Kopecka,
2012:250-257; Sandu et al, 2011:1171-1181).
73
Because the gilding process leads to the formation of a stratified, sandwich-like structure,
in which gilding metal sheet must be compatible with contact components its behavior
in time was studied using artificial ageing. For this purpose, the involved structures are
exposed to harsh environmental conditions, which lead to the alteration or micro-structural
destruction of the components. Their evolution can be determined by certain chemometric
characteristics (Sandu et al, 2000:532-542; Sandu et al, 2001:485-490).
Depending on the materials’ nature (organic or inorganic), the artificial ageing uses high
temperature (60°-110°C) and high relative humidity (85-99% RH) conditions or UV exposure
for short periods of time, equivalent to natural ageing during long time spans (Sandu et al,
2000:532-542; Sandu et al, 2001:485-490).
Excepting UV irradiation, which is very aggressive, with irreversible and un-controlled
effects, the other procedures are moderated, and their effects can be easily stopped. At
high temperatures there are dehydration processes which lead to structural modifications,
redox, acid-base, and complexation reactions, depending on the nature of the component
materials. Similarly, the atmospheres with high hygroscopic humidity affect especially the
hydrophilic organic materials. Thus, at humidity higher than 85%, the films or the thin layers
are transformed from un-membrane or semi-membrane systems in swollen membranes
which allow air oxygen diffusion. The oxygen interacts at interface level, leading to chemical
reactions and degradation of component materials (Sandu et al, 2000:532-542; Sandu et
al, 2001:485-490).
This paper presents the influence of shellac based protection film and of two “mixtion”
binders on the schlagmetal applied on a gessoed wooden support, using artificial ageing
with two different conditions: high temperature (65°C) and hygroscopic humidity (90%).
Materials and techniques
The samples were made of Balsa wood (20.5 mm x 20.5 mm x 5mm), following a traditional
recipe of mordant gilding. Thus, a few layers of ground made of CaCO3 and hide glue 10%
were brushed on the surface of the wood samples. After drying the ground was polished
with sand paper and isolated with shellac 20%. Drops of gilding sizes were spread by brush
on samples’ surface, and let to dry, respecting the time recommended by the manufacturer.
The metal sheet was applied and isolated with shellac 20%. 2 types of “mixtion”, with different compositions, produced by Masserini S.r.l and Maimeri were used. They were noted
as follows: water based “mixtion” – M-H2O, and the linseed oil based “mixtion”, with a 12
hours drying time, was noted M-12h. 2 samples were used for each type of “mixtion”. The
gilding sizes and shellac were applied by brush in a thin layer, respecting the drying time.
The 4 samples were exposed to artificial ageing. Two of them were placed in a thermoregulation oven AIR Concept (FIRLABO) type at 65°C, for 192 hours (the equivalent of 6 months
ageing at 20°C), while the other two were exposed to extreme humidity (90% RH) also for
192 hours, using an air-tight humidifier. The evolution of ageing effects were determined
by means of CIE L*a*b* colorimetry, every 48 hours.
74
M-H2O samples
M-12h samples
Figure 1 – The samples, coated with shellac, before the artificial ageing
at a temperature of 65° C (a) and 90% RH (b).
The samples morphology was analyzed using a reflection microscope CARL ZEISS AXIO
IMAGER A1m, having attached a photocamera AXIOCAM. Also, for the analysis of elemental
composition we used a scanning electron microscope, model VEGA II LSH, produced by
TESCAN Czech Republic, coupled with a spectrometer QUANTAX QX2, made by BRULER/
PROENTEC Germany. Schlagmetal’s colour changes were analyzed every 48 hours with
a spectrophotometer Lovibond RT 300. The color change was calculated for each color
coordinate (L*, a* and b*) as related to its initial value on the same sample and the same
point. Finally, the total color change (DE*) was calculated in each point (Atodiresei et al,
2013:165-169; Cristache et al, 2015:348-352; Daher et al, 2014:1207-1214; Le Gac et
al, 2013:242-257; Saviuc-Paval et al, 2012:170-178 and 2013:564-571; Sandu et al,
1999:902-908; 2007:879-886 and 2010:752-760; Schanda, 2007) using the equation
where DL* is the luminosity change in the respective point at different time intervals, by
artificial aging, comparative to initial value:
75
Da* is the change of the red (+a*) – green (-a*) coordinate in the respective point and at
different time intervals by artificial aging, compared to initial value
and Db* is the change of the yellow (+b*) – blue (-b*) coordinate in the respective point
and at different time intervals, by artificial aging, compared to initial value
s.aged – aged samples ; initial – initial samples.
Results and discussions
Initially the elemental compositions of the 2 types of “mixtion” were determined by means
of scanning electron microscopy, coupled with X-Ray spectrometry, SEM-EDX (table 1).
Table 1. The elemental composition of the “mixtions” used
Element
(norm.wt%)
Mixtion
M-H2O
M-12h
S
C
O
0.664887
-
27.81474
29.57225
71.52037
70.42775
The sulfur present in M- H2O composition was used to enhance “mixtion” adhesive properties
(Voitovich, 2010:133-136). The high quantity of carbon and oxygen is a result of organic
composition of the gilding sizes and of graphite conductive adhesive, used in microscopy.
The alcoholic solution of shellac 20% used to coat the ground layer and schlagmetal was made
of ethanol and refined natural resin, which contains 95% resin, 0.5% dyestuff (laccaic acid
and eritrolaccin), 4% wax and 1.8% volatile compounds. The resin contains sesquiterpenic
acids pertaining to cedrene, mostly jalaric and laccijalaric acids, and hidroxy fatty acids,
mainly threoaleuritic acid (Derry, 2012; Wang et al, 1999:1316-1322).
The 4 samples from figure 1 were studied by means of OM and SEM-EDX. Therefore in
figures 2 and 3 are presented the microphotographs made using the two techniques.
76
Figure 2 – Microphotographs of schlagmetal samples, with shellac and M-H2O (OM-100x): a –
before (1) and after (2) artificial ageing at 65°C,
b – before (1) and after (2) artificial ageing at 90% RH
Figure 3 – Microphotographs of schlagmetal samples, with shellac and M-12h (OM-100x): a –
before (1) and after (2) artificial ageing at 65°C,
b – before (1) and after (2) artificial ageing at 90% RH
The analysis by means of optical microscopy did not reveal notable changes of the schlagmetal’s surface between the shellac and “mixtion” films. The wrinkles and folds that can
be observed on some samples’ surface are a result of metal sheet spreading and irregular
drying of “mixtion” layer.
In table 2 is presented the elemental composition of schlagmetal.
Table 2 – Elemental composition of schlagmetal
Element
[norm. wt.-%]
[norm. at.-%]
Error in %
Copper
31.2674
9.647535
1.002499
Zinc
5.280557
1.583365
0.218092
Carbon
27.05418
44.16396
4.138933
Oxygen
36.39786
44.60514
8.5215
The schlagmetal composition contains, beside brass’ metals (Cu, Zn) a significant quantity
of carbon and oxygen from the graphite conductive adhesive, used in microscopy.
In figures 4 and 5 the SEM microphotographs are presented for the 4 samples, before (1)
and after (2) artificial ageing.
77
Figure 4 – Microphotographs of schlagmetal samples, with shellac and M-H2O (bse 100x): a –
before (1) and after (2) artificial ageing at 65°C, b – before (1) and after (2) artificial ageing in
humid atmosphere (90% RH)
Figure 5 – Microphotographs of schlagmetal samples, with shellac and M-12h (bse 100x): a –
before (1) and after (2) artificial ageing at 65°C, b – before (1) and after (2) artificial ageing in
humid atmosphere (90% RH)
The L*, a*, b* values (Table 3) obtained by colorimetric analysis of the artificially aged
samples at 65°C, were used to evaluate the colour differences ΔE* at different ageing stages,
according to the above formulae (Fig. 6).
Table 3. L*, a*, b* values of schlagmetal samples after temperature exposure
time
t=0
CIEL*a*b*
L*
M-H2O
86.61
M-12h
86.85
a*
+9.77
+9.30
t= 48h
b*
L*
+35.50
87.03
+34.68
87.59
a*
+9.80
+9.47
t=96h
b*
L*
+36.67
87.44
+35.61
88.40
a*
+9.84
+9.60
t= 144h
b*
L*
+37.40
87.83
+36.97
89.66
a*
+9.93
+9.80
b*
L*
+37.83
87.79
+37.78
88.67
a*
+10.01
+9.72
b*
+38.17
+37.59
t=192h
78
4.5
4
3.5
3
*
?
?
2.5
2
1.5
1
0.5
0
t ='0
t = 48h
t = 96h
t = 144h
t = 192h
? ? *M-H2O
0
1.24
2.07
2.63
2.92
? ? *M-12h
0
1.2
2.78
4.21
3.45
Figure 6 – The graphic for ΔE* colour differences of the two samples at different time spans
during thermal aging
Analyzing the samples exposed to high temperature, we observed an increment of ΔE*
values until t = 144h, the greatest variations occurring in the case of M-12h sample. After
144 hours the value of chromatic changes decrease only in the case of the M-12h sample,
while for the M-H2O sample slightly increases with a small slope. The biggest difference
between ΔE* values at t = 144h appear in the case of M-12h, 4.21 units, while the M-H2O
sample has a variation of 2.63 units, for the same time span.
From figure 6 we can observe that both colorimetric curves change their inclination after
144 hours of constant heating, which indicates a modification in the discolouration ageing
mechanism, due to dehydration and compaction of shellac, followed by an interaction with
the surface cations from the schlagmetal, which makes it darker.
After the measurements in CIEL*a*b* system of the samples exposed to humidity (table
4) and ΔE* calculations it was noticed that the samples presented an increase of the values
from t=0 to t=48h, which was greater in the case of M-H2O (4.29 units compared to 0.78
units in the case of M-12h), followed by a decrease of ΔE* values from t = 48h to t = 96h,
the highest variation appearing in the case of the M-H2O sample. Between t = 96h and t =
144h the ΔE* values increase, while at 192 hours, the slight change of ageing mechanism
lead to a significantly growth for the M-H2O sample and constant values for M-12h.
Table 4. L*, a*, b* values of schlagmetal samples after humidity exposure
time
t=0h
t=48h
CIEL*a*b*
L*
M-H2O
84.92
M-12h
89.15
a*
+9.60
+8.44
b*
L*
+35.67
88.86
+34.74
89.82
a*
+9.98
+8.55
b*
+37.33
+35.13
79
time
t=96h
CIEL*a*b*
L*
M-H2O
86.46
M-12h
89.37
a*
+9.84
+8.48
t= 144h
b*
L*
+36.51
86.54
+34.93
89.56
a*
+9.83
+8.48
t= 192
b*
L*
36.76
87.68
+35.08
89.56
a*
+9.96
+8.52
b*
+36.93
+35.08
5
4.5
4
3.5
*
?
?
3
2.5
2
1.5
1
0.5
0
t ='0
t = 48h
t = 96h
t = 144h
t = 192h
? ? *M-H2O
0
4.29
1.77
1.96
3.05
? ? *M-12h
0
0.78
0.29
0.53
0.54
Figure 7 – The graphic for ΔE* colour differences of the two samples
at different time spans during aging at high humidity
Conclusions
The samples with schlagmetal applied on water and oil based “mixtions” have suffered
colour changes under the influence of temperature and humidity, the ΔE* variations being
higher in the first case. The smallest variations determined by the temperature occurred in
the case of M-H2O sample, while the highest appeared in the M-12h sample. The situation
changes for the samples exposed to humidity, the M-12h sample being the one with the
smallest chromatic deviations, while the M-H2O presents the highest differences. This data
may help the artist/restorer to choose the right mixtion for gilding, also taking into account
the microclimatic conditions for object’s display.
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Acknowledgements
This work was supported by the strategic grant POSDRU/159/1.5/S/133652, co-financed
by the European Social Fund within the Sectorial Operational Program Human Resources
Development 2007 – 2013.
Authors’ short curriculum vitae
Ana –Maria Budu has a Bachelor Degree in Conservation and Restoration of Panel Paintings
(2006) from the Faculty of Orthodox Theology, “Alexandru I. Cuza” University from Iasi, a
master degree in Cultural Heritage Restoration (2008) by the same institution and is a PhD
Student in Environmental Science. Since 2006 she is working as a panel painting restorer.
Contact:
budu_anamaria@yahoo.com
Ioana Hutanu has a Bachelor Degree in Ecclesiastic Art, Department of Icon Restoration,
University “Alexandru Ioan Cuza”, Iasi, Romania and a MA in Cultural Heritage, Department
83
of Icon Restoration, University “Alexandru Ioan Cuza”, Iasi, Romania. She is a PhD Student
in Environmental Science (topic: Modern methods of consolidation and rehabilitation of
old paintings), at the Doctoral School of “Chemistry, Life Sciences and Earth”, University
“Alexandru Ioan Cuza”, Iaşi, Romania, coordinated by Prof. Univ. Dr. Ion Sandu.
Contact:
ioana24hutanu@yahoo.com
Viorica Vasilache is researcher at the Department of Interdisciplinary Research - the
Fields of Science,” Alexandru Ioan Cuza” University in Iasi, and a PhD in Chemistry. She is
specialized in scientific investigation of cultural heritage objects. She has published over 100
scientific papers including 30 in journals indexed in the Web of Science, with impact factor.
Contact:
viorica_18v@yahoo.com
Ion Sandu is Professor, Scientific Researcher and Laboratory Director at the Alexandru Ioan
Cuza University of Iaşi, Romania. His areas of expertise are scientific investigation, preservation and restoration of cultural heritage, environmental science and engineering, materials
science and engineering, forensic science, inventics. Supervizor PhD Thesis and Scientific
Research Project. Author: 63 books, 819 scientific papers (234 ISI) and 147 patents. Director
109 national research project and 6 UE project. Member in International Juries (ARCHIMEDES
- Moscow, NEW-TIMES - Sevastopol, INFOINVENT - Kishinew, INOVA – Zagreb, TESLAFEST
– Novi Sad). President of Romanian Inventors Forum. Editor in Chief: International Journal
of Conservation Science, Member of Scientific Boards: 16 Journals, Cited in other scientific
papers and patents: 760. Doctor Honoris Causa (Galati 2013, Sofia 2006, New York 1998),
Member of International Profesional Society: 16. Prises, Awards (150), Medals (507) and
Special Diplomas (145) for invents activity.
Contacto:
ion.sandu@uaic.ro
84

Estudos de Conservação e Restauro - SARC

Transcription

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