Page 1

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE

Postprints 2015


ACKNOWLEDGEMENTS The Editorial coordinators would like to acknowledge the contribution of the members of the Scientific Committee who made the selection of the papers for the Meeting.

Special thanks to all reviewers and referees who supported the postprints by reviewing and evaluating all submitted manuscripts to the RECH3 on a voluntary basis.In this postprint there are only the articles that have been peer reviewed.

We are grateful to Museu Nacional Soares dos Reis and the team of ARVORE for making this Meeting possible. We would also like to acknowledge to the conservators Susana Mendes, Alexandra Marco, Leonel Costa, Catarina Pereira, Rita Veiga, Leonor Loureiro and Liliana Cardeira for the help given during the Meeting.


Organizing and Executive Commitee from:

Scientific Commitee from:

Support:

3rd International Meeting on Retouching of Cultural Heritage, RECH3 Held at Museu Nacional Soares dos Reis in the City of Porto (Portugal), in October 23rd – 24th, 2015 Organized by Escola Artística e Profissional Árvore Title | RECH3: POSTPRINTS Published by | Escola Artística e Profissional Árvore Editorial coordinators| Ana Bailão, Frederico Henriques, Ana Bidarra Local and date | Porto, July 2016 Graphic Design | Ineditar Cover page| Ana Bailão and Frederico Henriques Legal Deposit | 411744/16

Responsibility for statements made in these papers rests solely with the contributors. The views expressed by individual authors are not necessarily those of the Editors or ARVORE.


International Meeting on Retouching of Cultural Heritage, RECH3

postprints of the 3rd Meeting

ORGANIZING COMMITTEE Ana Bailão (Universidade Católica Portuguesa/ CITAR, Portugal) Ana Bidarra (Cinábrio, Conservação e Restauro; Universidade de Aveiro/ GeoBioTec Research Centre, Portugal) Francisco Silva (Escola Artística e Profissional Árvore, Portugal) Frederico Henriques (Universidade Católica Portuguesa/ CITAR; HERCULES Lab, Portugal) Rui Bordalo (Évora University/ HERCULES Lab, Portugal)

SCIENTIFIC COMMITTEE Ana Calvo (Universidad Complutense de Madrid, Spain) Antonino Cosentino (Cultural Heritage Science Open Source) José Manuel de la Roja (Universidad Complutense de Madrid, Spain) Leonor Loureiro (Polytechnic Institute of Tomar, Portugal) Leslie Carlyle (FCT, New University of Lisbon, Portugal) Mary Kempski (Hamilton Kerr Institute, University of Cambridge, UK) Silvia García Fernández-Villa (Complutense University, Madrid, Spain) Sandra Sústic (University of Zagreb, Croatia)

PEER REVIEWERS Alice Alves (Faculty of Fine Arts, University of Lisbon, Portugal) Ana Calvo (Universidad Complutense de Madrid, Spain) Antonino Cosentino (Cultural Heritage Science Open Source) José Manuel de la Roja (Universidad Complutense de Madrid, Spain) Laura Fuster-López (Faculty of Fine Arts, Polytechnic University of Valencia, Spain) Leonor Loureiro (Polytechnic Institute of Tomar, Portugal) Leonardo Severini (University of Urbino; University of Viterbo) Lorenzo Marchet (CESMAR 7) Mary Kempski (Hamilton Kerr Institute, University of Cambridge, UK) Marta Frade (Faculty of Fine Arts, University of Lisbon, Portugal) Ricardo Triaes (Polytechnic Institute of Tomar, Portugal) Silvia García Fernández-Villa (Complutense University, Madrid, Spain) Sandra Sústic (University of Zagreb, Croatia) Cristina Montagner (Centre of Physics, Campus de Gualtar, University of Minho, Portugal)


authors index

Alexandre Fernandes

Joana Júlio

Alexandre Gonçalves

Leonor Loureiro

Ana Bailão

Leslie Carlyle

Ana Bidarra

Liliana Cardeira

Ana Calvo

Liliana Silva

Ana Catarina Rosa

Lucija Močnik Ramovš

Antonino Cosentino

Luís Bravo Pereira

António Candeias

Luísa Carvalho

Barbka Gosar Hirci

Maria Cristina Coelho Duarte

Carol Pottasch

Marta Manso

Carolina Ferreira

Mary Kempski

Catarina Pereira

Mercês Lorena

Cátia Silva

Mohamed Abdeldayem Ahmed Soltan

Christou Vasiliki

Pedro Antunes

Débora dos Santos Lopes

Raquel Marques

Eduarda Vieira

Rūta Kasiulytė

Elsa Murta

Sandra Šustić

Fernando António Baptista Pereira

Sarah Maisey

Filipa Quatorze

Silvia García Fernández-Villa

Francisco Brites

Sofia Gomes

Frederico Henriques

Sónia Costa

Giuseppe Agulli

Susan Smelt

Glória Nascimento

Theochari Angeliki


INDEX I.

Plaster sculptures from the national museum of Soares dos Reis: cleaning methodologies to achieve colour re-integration 9

Alexandre Fernandes; Elsa Murta

II. The “value-function” attributed to cultural heritage as a criterion for reconstruction or reintegration: the paintings 17

Ana Bailão; Ana Calvo

III. Perspectives on the restoration of porcelain - selecting the retouching method

23

Ana Bidarra; Filipa Quatorze; Pedro Antunes

IV. Crowd funded research: low-cost multispectral imaging

33

V. Use of retouching colours based on resin binders – from theory into practice

43

Antonino Cosentino

Barbka Gosar Hirci; Lucija Močnik Ramovš

VI. Bringing the Rembrandt back to life: the retouching of Saul and David

53

Carol Pottasch; Susan Smelt

VII. Materials and techniques for retouching glass plate photographic 65 negatives in the beginning of the 20th century

Catarina Pereira

VIII. Hand building a low profile textured fill for a paint/ground loss

Francisco Brites, Leslie Carlyle; Raquel Marques

IX. Heritage documentation and 3D retouching of virtual objects

73 83

Frederico Henriques; António Candeias; Alexandre Gonçalves; Eduarda Vieira

X. Treatment of lacunae, gestalt psychology and cesare brandi. From theory to practice 93

Giuseppe Agulli; Liliana Silva

XI. Different hands, different paintings, one retouching - the conservation project of the Funchal’s cathedral altarpiece 103

Glória Nascimento; Sofia Gomes; Carolina Ferreira; Joana Júlio; Mercês Lorena; António Candeias

XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces 113

Leonor Loureiro; Cátia Silva; Ana Catarina Rosa


XIII. Adriano de Sousa Lopes, batalha entre gregos e troianos – the painting collection of fbaul 123

Liliana Cardeira; Fernando António Baptista Pereira; António Candeias; Sónia Costa; Luísa Carvalho; Marta Manso

XIV. Hyperspectral imaging applied to the study of paintings color

133

Luís Bravo Pereira

XV. Approaches to restoration at the Hamilton Kerr Institute and the use of egg tempera as a retouching medium 143

Mary Kempski

XVI. An investigation into the image reintegration of airbrush easel paintings

153

Mohamed Abdeldayem Ahmed Soltan

XVII. Further developments on the use of Beva® gesso-p infills and solutions for reintegration of a large loss 163

Raquel Marques; Leslie Carlyle

XVIII. Retouching methodology - when a painting is composed of seven compositions 173

Rūta Kasiulytė

XIX. Decoding old master paintings: examples from the Croatian Conservation Institute 179

Sandra Šustić

XX. Retouching and reconstruction of major compositional losses in paintings: the use of digital reconstructions based on related historical material 189

Sarah Maisey

XXI. Filling as retouching: the use of coloured fillers in the retouching of contemporary matte paintings 199

Silvia García Fernández-Villa

XXII. Study of technology and condition survey of pigments of marble elements on the academy of athens 209

Theochari Angeliki; Christou Vasiliki

XXIII. Pictorial restoration- the training of craftsmen at the oficina escola de manguinhos 217

Maria Cristina Coelho Duarte; Débora dos Santos Lopes


FOREWORD The retouching is a stage of the restoration intervention. It is a very specific process that is not intended to stabilize the condition of the object in a physical sense but merely to change the way we perceive it. It is also one of last the things to be done during the intervention, and obviously, is one of the most visible parts of conservator-restorers work. Depending from of the geographical location, the retouching process is a called many different names such as inpainting, integration, re-integration, reintegration, image reintegration or loss compensation. If the way of defining the task is so multiple, it is completely understandable that the criteria to follow and the methods and materials to use are numerous and almost infinite per se. The main focus of RECH is to promote the exchange of ideas, concepts, terminology, methods, techniques and materials applied to the retouching process among professionals, students and investigators of conservation of Portugal and other countries and cultures and in different areas of conservation: mural painting, easel painting, sculpture, graphic documentation, retirar architectural, plasterwork, photography and contemporary art, among others. Also, RECH Meetings provided an excellent opportunity for friendly discussion about all kinds of ideas related to the Retouching process/methods in Cultural Heritage. This postprints summarized some of the studies from Portugal, Spain, Italy, Slovenia, Lithuania, Netherlands, United Kingdom, Egypt, Croatia, Greece and Brazil. These investigations strengthen the relationship between the retouching process and the conservator. The first International Meeting on Retouching of Cultural Heritage (RECH), held in 2013, presented the experiences from private and academic conservators about this issue, especially from Portugal and Spain. However, the second and third editions, in 2014 and 2015, has attracted even more international attention. Hopefully this conference will continue to be a platform for improving and sharing our retouching practices between countries and also to increase better understanding about our criteria and our deontological actions. To finish, on behalf of the organizing committee, I would like to thank all the colleagues, professionals and friends who help in this event.

May 27th, 2016 Ana Bailão RECH3 conference chair


I

Plaster SCULPTURES FROM The National Museum of SOARES DOS REIS:

CLEANING METHODOLOGIES TO ACHIEVE COLOUR RE-INTEGRATION


I.

Plaster SCULPTURES FROM The National Museum of SOARES DOS REIS:

Alexandre Fernandes (1), Elsa Murta (2)

CLEANING METHODOLOGIES TO ACHIEVE COLOUR RE-INTEGRATION

(1) Fundação para a Ciência e a Tecnologia / Laboratório José de Figueiredo; Rua das Janelas Verdes, n.º 37 1249-018 Lisboa, Portugal; alexandrefsfernandes@gmail.com (2) Laboratório José de Figueiredo; Rua das Janelas Verdes, n.º 37, 1249-018 Lisboa, Portugal; elsa.murta@gmail.com

Abstract The sculpture collection of the National Museum of Soares dos Reis, in the city of Porto, includes a significant number of original sculpture pieces and copies belonging to the important Portuguese sculptor António Soares dos Reis. The author, from the second half of the 19th century, also lent the name to the Museum in 1911. A relevant part of this collection are the original plaster models for the definitive sculptures executed through moulding processes, which includes busts portraying several notable people, bas-reliefs or moulds made of marble, bronze or plaster. The use of gypsum, as part of the modelling work, would facilitate the artist’s modelling process. However, many problems related to its state of conservation began to emerge over time. A widely and varied specific set of pathologies can be identified. Some are due to the inherent fragility of this type of material, others related either to the achromatic layer or as a surface colouring technique to imitate clay or bronze. Assuming that each case has its own merit and the original appearance and colouring of this particular material will be the main purpose, can cleaning methodologies be regarded as a method of colour re-integration?

Keywords Colour re-integration; Plaster; Aesthetic; Patina.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

11


I. PLASTER SCULPTURES FROM THE NATIONAL MUSEUM OF SOARES DOS REIS

1. Introduction Plaster was used essentially as a “sacrificial” material for studies or models due to its singular properties, as it would allow a much easier surface work and manipulation for the artist, becoming very common throughout the late 17th, 18th and most especially the 19th century [1]. Therefore, some pathological issues concerning the state of conservation of some plaster sculptures are due to its predominance in value as a whole compared with the final artworks. Some of these superficial problems, such as abrasion or dirt accumulation, along with the presence of patina, raises some important issues concerning its aesthetical presentation. This study aims to reveal the most convenient and ethical methodology for the return of the structural integrity and aesthetic appreciation in such achromatic artworks. Thus, some of the plaster pieces belonging to the Museum’s sculpture collection that were subjected to a conservation and restoration treatment, will be further presented.

will allow to set hard as a solid material (calcium sulphate di-hydrate). This process produces heat and expansion. Its final appearance is white and dense. However, plaster is a hydrophilic material and can be very porous depending on the relation between solid and water in the original mixture. It can also contain impurities, such as iron or silicates that can alter the perception of colour as the material ages [2].

2.2. Material techniques

Plater had a significant use as a casting material in the statuary process of creation and reproduction by the well-known method of lost mould. Traditionally the surface was sealed with linseed oil and before the appearance of silicone, gelatine was applied onto the model. The plaster model made from a lost cast could be reworked, eliminating the joins that occur when the mould was cast in sections. The final model should contain metal or wood skeletons for structure stability and it would be the early point for the production of a series of plaster copies in various materials, such as marble or bronze, using the sand or lost wax casting processes [2].

2. Materials and methods 2.1. Material characteristics

Gypsum is usually referred to as plaster of Paris or by its Italian name, Gesso. It is prepared by heating di-hydrated calcium sulphate, naturally deposited in gypsum materials, at between 100° - 150°C to evaporate some of the crystallization water. Later, by adding water, it

12

2.3. Conservation issues

Most part of the collections where plaster sculptures like those are gathered can be reduced to three distinct groups. One group of plasters that have been left untreated or unprotected. A second group of sculptures that have received some kind of coating or surface protection and a third one that have


I. PLASTER SCULPTURES FROM THE NATIONAL MUSEUM OF SOARES DOS REIS

been painted (some plasters are painted in a muddled manner using different shades of brown to highlight the volume of the object and others painted to imitate the appearance of metal, such as bronze) [1]. Consequently, this kind of sculptures are susceptible to a wide range of internal and external factors that add some pathological issues that contribute to its preservation condition and thus its superficial alteration, such as: Dirt, dust and atmospheric pollution that can deposit at the surface of plaster works. The outside pollution is usually generated by combustion processes, acidic gaseous pollutants or natural sources, like salts. Depending on the degree of superficial protection, if plaster casts are more porous than others or left untreated, the dirt accumulation can penetrate easily over time into the material and be a welcoming host for fungal growth, which is evidenced on plaster as darkened areas with a pitting phenomenon. The slightest dirt accumulation can alter colour and soiling can alter the sculpture detail and shape perception; The catalyst for all deterioration processes to plaster surfaces seem to be high humidity levels. Humidity and condensation are the most important factor in the cementation of dust to surfaces where a dark grey-brown to a black kind of film can be noticed. Plaster with no surface protection can be more prone to surface erosion and abrasion than other with coatings. Over time, if erosion is a severe problem, details of the work at the surface can be lost, mostly on bas-reliefs. Some models containing points of measurement, or primary works, which still conserves marks due to the sculptor tools, can also vanish; Metal oxidation. Since plaster can

be porous and is a very hygroscopic material, within adverse environmental conditions with high levels of humidity, sculptures that have constructive and auxiliary materials like iron, corrosion can be formed at the surface of the metal, expanding its volume and thus cracking the plaster from the inside. This alteration also stains superficially the nearby plaster. This material is fragile in its essence and it was chosen by the artist for its modelling properties and as a “sacrificial� material. Therefore, it can effortlessly fracture over inappropriate handling, leading sometimes to missing parts of material, which can alter the aesthetic appreciation of the plaster artwork; Superficial alteration. Coatings vary in appearance from a yellowish, more or less transparent film to a clear one, giving the plaster the appearance of a saturated and polished surface. Over time, chemical alterations, among dirt and pollution deposits occur, modifying the coatings colour, giving the plaster casts a yellowish and darker appearance; Besides the residual matter left at the surface used as an interface for the moulding, some other interventions were took over time to modify the appearance of plaster sculptures, like the overpaint in painted plaster, past cleaning interventions with brushes or sponges, the application of a whitewash to hide imperfections and alterations or residual adhesives used in collages. In addition, human contact, through deposition of sweat and grease on the plaster surface, can stain, acquire a gloss and thus modify its achromatic appearance.

2.4. Presentation challenges

Among lithoid objects, plaster artefacts

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

13


I. PLASTER SCULPTURES FROM THE NATIONAL MUSEUM OF SOARES DOS REIS

certainly seem to be the most difficult to clean. In order to preserve it is necessary to discriminate between intentionally white surfaces, those that also present various colorations, like painting layers, intentional patinas for aging appearance and substances applied for the model detaching purposes. Patina itself also has an ambiguous definition. According to Ana Calvo, patina is a surface coating produced by the passage of time in the materials, with historic validity, through environmental influence. Moreover, a whole range of effects of the aging process of materials contributes to this phenomenon, generating a difficult consensus at establish the limits and definition of patina [3]. Nevertheless, aesthetic relies itself in the appearance of the work of art and its understanding cannot be dissociated from its presentation.

2.4.1. Case 1

The first case presented is the mortuary mould mask in plaster from the sculptor, made by Teixeira Lopes, with several issues regarding its presentation. This mould belongs to the group of plasters that have been left untreated or unprotected. The dust and dirt deposit and inventory number stamp residues where the most obvious, darkening the basic white colour of the plaster. A mechanical intervention using a very soft brush and a sponge rubber [4] were selected for a conservation treatment.

14

Figure 1. Soares dos Reis mortuary mask (before and after treatment)

2.4.2. Case 2

The second case is the study for the hands of the sculptor’s masterpiece O Desterrado. This artwork also belongs to a group of plasters that have been left untreated or unprotected. Dirt deposits are noticeable such as yellowed and blackened spots in the surface, due probably, to human contact. Apart from the same mechanical action to remove dirt, it was necessary to proceed with a chemical cleaning using volatile solvents (high evaporation level) to attenuate the presence of the major stains at the surface.

2.4.3. Case 3

Figure 2. Model for O Desterrado hands (before and after treatment).

The third case is a copy from last century of an original Soares dos Reis sculpture, and represents a crucified Christ in plaster and


I. PLASTER SCULPTURES FROM THE NATIONAL MUSEUM OF SOARES DOS REIS

painted to imitate bronze. This last case presented belongs to the group of plasters that have been painted to imitate bronze. Cracking and loss of material where obvious issues among dust deposit. Once this was a painted sculpture, and besides the structural lack of stability due to fractures, the plaster and colour loss was a great problematic in terms of the aesthetic presentation. After a superficial and mechanical dust deposits cleaning, the fragments and cracks were glued and areas of loss completed with a synthetic filler. Finally, colour integration in the areas of loss were applied.

Figure 3. Crucified Christ (before and after treatment).

How can the historical instance be respected (patina) as much as the artist’s intention? How can a conservator-restorer, even with concerted decisions with the museum or owner, manage to aim both the viewer and historians or curator’s expectations? According to Brandi, the passage of time should not be erased, as there are some aesthetical issues to ponder, such as the artist’s intention or how the work was supposed to be seen and the passage of time since the work was produced till today [5]. Paul Philippot also corroborates this by stating that trying to eliminate the problem of patina would mean to ignore the evolution of the material and the relationship between the original state and the present state of the material. Patina is also an aesthetic reality and integrant part of the work. However, the author adds that considering a work of total white such as plaster, if it becomes yellow or greyish and no longer expresses its aesthetical intention, it can be arguable whether to keep the work’s patina (representing its historical instance) or to remove it (representing its aesthetic instance) [6]. Bearing in mind the concept of minimal

3. RESULTS and Discussion After dealing with these cases, some unavoidable questions and different points of view arise: In such achromatic works due to the material characteristics, how far can one “insist” in order to give back both matter and the artwork aesthetic the dignity it deserves?

intervention, we as conservators-restorers, may have some issues at balancing these two distinct concepts, the artist’s creative intent and the conservator’s intent for longevity when defining a conservation and restoration plan. For that reason, the conservator-restorer has always to carry out his decisions on the artwork itself, as the technological study and critical definition of the object only constitutes the point of departure for a conservation treatment

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

15


I. PLASTER SCULPTURES FROM THE NATIONAL MUSEUM OF SOARES DOS REIS

[7]. In addition, according to Paul Philippot, the conservator’s decisions can determine the appearance of the work, who is, in effect, forced to concretize a critical judgement on the work itself.

[1] MARQUES, Sofia - The Plaster Cast Courts Project: an introduction. Conservation Journal, Issue 61 (2013); http://www.vam.ac.uk/content/journals/conservationjournal/spring-2013-issue-61/the-plaster-cast-courtsproject-an-introduction / [5 October 2015].

Moreover, the disturbances caused by the lack of material, also makes it difficult to perceive the image because, losses are an interruption of the continuity of the form. From an aesthetic viewpoint, Philippot sustains, the work of art is characterized by the unity of the form as a whole, and so reconstruction is justifiable as long as it aims only at making it easier to see the potential formal unity of the work.

[2] BADDE, Aurelia - Dusts on Busts - Dust on Plaster Surfaces: Focusing on the Portrait Busts in the Rococo Hall of the Duchess Anna Amalia Library in Weimar. p. 18; http://www.klassikstiftung.de/uploads/ tx_ lombkswdigitaldocs/Badde_Dusts_on_Busts.pdf / [8 October 2015].

Consequently, material re-integration can be nothing than other but an attempt to reconcile and a way to balance the historical with the aesthetic, a matter of reducing damage without slipping into falsification [8].Retouching is also a way to establish a flow to an artwork aesthetic perception [9].

[5] BRANDI, Cesare - Teoria do Restauro. Amadora: Edições Orion, 2006.

4. CONCLusions The questions raised may not have an objective answer as each artwork, with distinct pathological issues, has its own merit. One conservation and restoration approach may not be applicable to all plaster surfaces. The passage of time (patina), pathological (damages) and presentation issues in such specific material, demand different approaches in order to conciliate the artist’s intention, and the artwork’s historical factor.

16

REFERENCES

[3] CALVO, Ana - Conservación y restauración, Materiales, técnicas y procedimentos, De la A a la Z. Barcelona: Ediciones del Serbal, 1997, p. 167. [4] BARKLAY, Robert L. - Care of Objects Made of Plaster of Paris, CCI Notes 12/2, Canadian Conservation Institute, p. 2; http://canada.pch.gc.ca/eng/1439925170729 [22 February 2016].

[6] PHILIPPOT, Paul - The Idea of Patina and the Cleaning of Paintings, Readings in Conservation - Historical and Philosophical Issues in the Conservation of Cultural Heritage, The J. Paul Getty Trust, 1996, p. 373. [7] ALBANO, Albert - Art in Transition, Readings in Conservation - Historical and Philosophical Issues in the Conservation of Cultural Heritage, The J. Paul Getty Trust, 1996, p. 166, 169 [8] PHILIPPOT, Paul - Restoration from the Perspective of the Humanities, Readings in Conservation - Historical and Philosophical Issues in the Conservation of Cultural Heritage. The J. Paul Getty Trust, 1996, pp. 227, 228. [9] PHILIPPOT, Paul - The Problem of the Integration of Lacunae in the Restoration of Paintings, Readings in Conservation Historical and Philosophical Issues in the Conservation of Cultural Heritage, The J. Paul Getty Trust, 1996, p. 337.


II

The “value-function� attributed to cultural heritage as a criterion for reconstruction or reintegration: the paintings


II.

The “value-function” attributed to cultural heritage as a criterion for reconstruction or reintegration: the paintings

Ana Bailão (1), Ana Calvo (2) (1) Universidade Católica Portuguesa (UCP); Escola das Artes; Centro de Investigação em Ciência e Tecnologia das Artes (CITAR); Rua Diogo de Botelho, 1327, 4169-005 Porto; E-mail address: ana.bailao@gmail.com (2) Universidad Complutense de Madrid, Calle El Greco 2, Madrid; E-mail address: ancalvo@art.ucm.es

Abstract The intervention criteria applied to old objects and paintings in each historical period, in the treatment of reconstruction and reintegration of the form and the lost colours, has depended of the value-function attributed. The conservation and restoration processes applied in each period have relied on the values given to each type of goods. So it has been able to prevail the aesthetic, historical, documentary, or other values. To understand the history of interventions in the objects of the past it is necessary first understand the social and cultural bases that determine the criteria used at different times and in different cultures. Furthermore, the current criteria for reintegration are determined by the “values” that now we apply to different cultural objects, including paintings by their role or function at this time.

Keywords Chromatic reintegration; Painting; Value; Function.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

19


II. The “value-function” attributed to cultural heritage as a criterion for reconstruction or reintegration: the paintings

1. Introduction The present article synthetize the main values considered by important figures of conservation theory like Alois Riegl, Gustavo Giovannoni and Cesare Brandi and from contemporary conservation theory Salvador Muñoz Viñas. The authors will be presented by chronological order. Although not specifically referring to painting, Riegl and Giovannoni, the first two authors mentioned, could be the source of inspiration for the later authors. The aim of this study is to understand and evaluate the values that determine the criteria of the interventions used at different times and in different cultures.

2. ALOIS RIEGL Values assigned by Riegl, and in the context of monuments, allude to some of the important principles in the ethics of conservation and restoration, such as respect for the original and the historical and documentary value, that are relevant before the intervention decision and during the process of conservation and/or restoration. The distinct values coexist and Riegl recognize that these are often contradictory. Take the case of “antiquity value”, which is contrary to the “novelty value” and may come into confrontation with the “use value” and the “historical value”. The “utility value”, in turn, can contradict the “artistic value relative” and “historical value.” Alois Riegl establishes two categories: the “memorable” monuments, which have implied 20

the definition of values linked to the past, and the monuments of the “contemporary”, associated with the present values. Within the first category, distinguishes the monument with “antiquity value”, those with “historical value” or “intentional recall value.” Riegl considers that each of these types of monuments have different requirements and needs in case of intervention [1].

3. Gustavo Giovannoni As Riegl, the thought of Gustavo Giovannoni is also directed to the architecture, but the way it interprets the monuments helps to define intervention strategies for movable property. Giovannoni advocates an evolutionary conception of art and as a result, the preservation of the remains of the different periods that can be present in a work of art, trying to counteract the historical reality with aesthetic problems. He understands the monument as a document, in the continuity of the theories of Boito, which can be a “dead monument” as the case of archaeological monuments that have not a utilitarian function, or a “living monument”, which retains its original function or another, but that fits the present reality. Giovannoni included in his concept of “monument” not only the great buildings that have marked the history of architecture, but also more modest works when their historical and artistic value can be integrated into the context and studied as a whole. This comprehensive notion of Giovannoni has modified the way the concept of heritage was understood [2].


II. The “value-function” attributed to cultural heritage as a criterion for reconstruction or reintegration: the paintings

4. Cesare BRANDI

associated with ritual, symbolism and iconography, and the material function, related

Brandi, considering the specific problem of the reintegration of paintings refers to the potential unity of the work of art that is invalidated by the presence of losses or lacunas. Reintegration responds to the need to return to the work of art its aesthetic and expressive capacity,

to the creation of the work, the techné. In the first situation, where the losses interfere with the iconographic reading and the spirituality or the ritual of a community, it is considered the reconstitution of the work so that it can fulfil its function or role. Reintegration is performed when there is formal and chromatic and / or photographic or graphic documentation. In the second case, the decision depends on several actors and so can vary between nonintervention, minimal intervention or full reintegration (mimetic or differentiated) [5].

respecting the historic character of the losses, so the retouchings or inpaintings should be differentiated so that not incurred in a historical or artistic false [3].

5. Salvador Muñoz Viñas In the context of contemporary theory were adopted other values, such as the symbolic, religious, economic, personal, sentimental, tourism, functional, among others. The huge variety of objects make it impossible to use the term historical-artistic just for classified objects, being the “artistic” concept, many times, also inaccurate because it changes over time, and because it depends on the type of training of each person / observer. The value also depends on the personal interpretation of each viewer. Also for this reason exists the classification of “cultural heritage” for the objects [4]. In the context of the various values that a work of art can have, we consider that two of them related to each other, can help in reintegration decision-making: the heritage function and the symbolic character of the object at the time of the intervention. The function can be divided into two categories: spiritual contemplation,

6. CONCLusions Despite the decision-making for the retouching process, there can always be some controversy, since the notion of what should be reconstructed or not, varies from individual to individual according to their values, social context and subjectivity. For this reason, any decision about reintegrate or not, about the appropriate method, technique and materials, should be collective, either by a “group of experts” who analyse the work, or by a collective representing the many viewers of the object, to be possible to appreciate different “values”.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

21


II. The “value-function” attributed to cultural heritage as a criterion for reconstruction or reintegration: the paintings

REFERences [1] RIEGL, Alois – Le culte moderne des monuments: son essence et sa genèse. Paris: Éditions du Seuil, 1984. [2] GIOVANNONI, Gustavo – Il Restauro dei monumenti. Roma: Cremonese, 1946. [3] BRANDI, Cesare – Teoria do Restauro. Amadora: Edições Orion, 2006. [4] MUÑOZ VIÑAS, Salvador – Teoría contemporánea de la Restauración. Madrid: Editorial Sintesis, 2003. [5] BAILÃO, Ana Maria dos Santos – Critérios de intervenção e estratégias para a avaliação da qualidade da reintegração cromática em pintura. Porto: Universidade Católica Portuguesa, 2015. PhD thesis.

22


III

Perspectives on the restoration of porcelain - selecting the retouching method


III.

Perspectives on the restoration of porcelain - selecting the retouching method

Ana Bidarra (1, 2), Filipa Quatorze (3), Pedro Antunes (1)

(1) Cinábrio – Conservação e Restauro; bidarra.ana@gmail.com; cinabriocr@gmail.com

(2) GeoBioTec Research Centre – Aveiro University, Portugal

(3) Museu da Vista Alegre - Vista Alegre Atlantis – Ílhavo, Portugal; filipaquatorze@vistaalegre.com

Abstract The restoration of porcelain, particularly utilitarian and decorative, often follows techniques and methods that can easily conflict with the current theories of conservation. The objects in this case study were manufactured by Vista Alegre Porcelain Factory (Ílhavo, Portugal) and will integrate the permanent collection of the renewed factory museum. This artworks are a small part of the 2000 pieces that will be exhibited and that were also subjected to a previous conservation treatment. Among this 2000 works – ranging from the beginning of the 19th century until the 21st century - a first group of 15 objects were selected for restoration, due its poor condition, which made them unsuitable for display. This 15 objects although similar in materials – polychromed glazed porcelain – are very different in typology, size and preservation condition: some were glued, some had cement on the inside, lacunas, fillings, oxidation stains or were broken in several fragments. The main purpose of the conservation and restoration work was to promote a methodology that could be applied not only to the 15 selected objects, but to the other works that are still in need of restoration. The main goals were to stop or diminish the interferences that distracted the reading of the objects as a whole, to keep the restoration recognizable and to limit the intervention to a minimum. The combination of these criteria with the nature of the material – recent porcelain, with a uniform, flawless and extensive monochromatic glazed surface – pointed to a mimetic retouch. The nature of the material was also decisive in the selection of the materials and techniques airbrush retouching process.

Keywords Porcelain; Restoration; Mimetic retouching; Airbrush; Vista Alegre Museum.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

25


III. Perspectives on the restoration of porcelain - selecting the retouching method

1. Introduction 1.1. Vista Alegre Porcelain Fabric – Historical perspective

It was only in the 19th century, marked by the echoes of the French Revolution, the first industrialization efforts and a profound change of mentalities, tastes and habits of consumerism in the Portuguese society, that the necessary conditions were met for the implementation of the first porcelain production unit in Portugal [1]. In the year of 1824 José Ferreira Pinto Basto addressed a petition to the King D. João VI for the establishment of the Vista Alegre Porcelain Factory, in the city of Ílhavo, Portugal. Herein introducing the financial, technological and social requirements for the establishment of the factory, José Ferreira Pinto Basto set up the foundations of a family enterprise, calling all its children to participate with ‘equal interests’ in the establishment of a ‘large factory for the production of pottery, porcelain, glass work and chemical processes’. King João VI agreed, considering that the Factory “Would be of great use to the people for the vastness of its various branches; that its location is most advantageous for its excellent clay and fine sand, well suited to the glass and porcelain industries, and, lastly, that the supplicant is a man of great enterprise who will not be thwarted by difficulties nor be put off by expense”, as can be seen in the Royal Charter of July 1st 1824.

26

a daring tradesman with a pugnacious and persevering personality [2]. Having recognized the commercial and financial potential of this enterprise as well as its cultural relevance since the early stages, José Ferreira Pinto Basto managed to overcome the initial difficulties thanks to his business skills and vision. In reality, the history of Vista Alegre is inseparable from this personage, whose spirit deeply carved the trails trekked by the company throughout its 192 years of existence (Figure 1).

Figure 1. Vista Alegre Factory main entrance.

1.2. Preparing 2000 objects for exhibition

José Ferreira Pinto Basto’s spirit of persistence was a determining factor in the founding and success of this risky industrial undertaking. He was an important figure in 19th century’s

The Vista Alegre Historical Museum integrate the Porcelain Factory complex and was first open to the public in 1964. Objects from the industrial unit, as well as acquisitions and donations, have been added to the Museum’s collections over the years. Currently the Museum is being remodelled and all areas and contents updated. Due to this extensive renovation several objects have been selected to integrate the new Museum, including some kept in the Storage Department.

Portuguese society – an agricultural proprietor,

The first part of the work consisted on the


III. Perspectives on the restoration of porcelain - selecting the retouching method

conservation treatment of approximately 2000 objects. The vast majority of the intervention comprised the cleaning of the surface (Figure 2). The main challenge was to define the process for the different types of decoration: glazed or unglazed (biscuit), hand painting (by brush or pen) or transfer printing, decoration with precious metals, such as gold or platinum and even some previously restored objects. Some of the objects were poorly glued and the adhesive had yellowed or was applied in excess. In this cases the pieces were detached and properly bonded. Oxidised elements such as iron and brass internal spurs were treated – the oxidation was mechanical removed and a protective layer of Paraloid B72 in acetone was applied [3] [4] [5].

Figure 2. Conservation treatment: cleaning.

sculptures, but also a fruit-bowl and a nightlight. The heights vary form a few centimetres (4,5cm) to a 130cm vase. Although there were other pieces in need of restoration the selected objects carry a historical and symbolical significance that complement the museological narrative. Some of the most emblematic works are: the regional figurine “Alentejano” (part of a collection of thirteen sculptures created in 1959). The model was designed by the Portuguese sculptor, Cabral Antunes, and decorated by Jeanine Hetreau, interior designer that worked with Vista Alegre in the same period of time. The fruit-bowl “Gameiro”, designed by the sculptor Ruy Roque Gameiro, created in 1930. It embodies the modernist spirit with its unusual purple colours and its classical and geometrical shapes (Figure 3).

Figure 3. a) “Gameiro” fruit-bowl; b) Original drawing (study) (MVA_FOT_42_Estudo para fruteiro); c) Entry sheet (MVA_FP000_Fruteiro Gameiro_926_A).

1.3. Selecting the objects for restoration

Among the objects that were selected for the Museum, some were in need of a more profound intervention due to its poor condition. Fifteen objects were selected, that presented different alterations: fissures, fractures, lacunas and poor restoration works. This objects range from the late 19th to the 20th century and comprise different typologies particularly vases and

The sculpture “Amigo da Onça”, was a special order to the Vista Alegre Factory, based on a Brazilian comic strip, published since the 40’s, by the author Péricles de Andrade Maranhão. The night-light “Choupana” is a model that dates back to the 19th century, taking the shape of a country house, with the representation of a female figure in one of the sides. These

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

27


III. Perspectives on the restoration of porcelain - selecting the retouching method

pieces, also known as veilleuses, were used to light the rooms of the ill or sick. On the base we would have the recipient with an inflammable substance and on top a small tea-pot, thus providing light and keeping the tea or broth warm. The vase “Japoneza”, with decoration by Leitão de Barros, was created in 1928. It is a very classical shape but with a geometrical and floral decoration. The vase “Hannover”, decorated with stylized regional motifs by the artist Manuel Piló, in 1938 symbolizes the approach to modernist styles and also the stylization of regional motifs, typical of the 30’s and 40’s of the 20th century (Figure 4).

Figure 4. a) b) Piló original drawings (MVA_DES_1741E_A) (MVA_ DES_1741K_A); c) Entry sheet (MVA_FP000_JARRA HANOVER N2_P 1815_A).

2. Materials and methods 2.1. Introduction

In other areas of conservation, such as painting or sculpture, many of the materials employed in the conservation and restoration treatments have the same nature has the original. Fillings and reconstructions can be made using canvas or wood, the application of a ground layer is often made with a gesso or chalk base diluted in animal glue. Some of the methods applied are similar to those used in the manufacture. Although some attempts have been made to use the same materials and techniques in the restoration of porcelain, the results were far from good [3]. Currently there are various materials available. The choice is based mainly in the characteristics of the object and its function. In this particular case the main goal was to achieve a coherent result concerning the restoration treatment of 15 objects integrated in a vast collection of 2000 objects.

2.2. Bonding and filling

A vase by Manuel Cargaleiro (1927) - a ceramist and plastic artist -, designed exclusively for Vista Alegre in 1956. This vase combines a strong shape, with geometrical decoration and gold painting. And finally two vases of large dimensions, hand painted by Palmiro Peixe, replicas of the ones made in the 1940’s for the Bank of Angola.

28

The objects that were in poorer state of conservation and needed a more profound intervention were the vases by Cargaleiro, Piló and Palmiro Peixe. This presented different challenges particularly due to its condition: the Cargaleiro vase (35cm) was broken in 16 fragments and had one lacuna on the top and one of the Palmiro Peixe vases (a 130cm object) was broken in six fragments glued in the inside with cement. The Piló vase, although small (21cm) was broken in two fragments and the joint crossed the middle of one of the figurines; there were also some noticeable lacunas in the top and


III. Perspectives on the restoration of porcelain - selecting the retouching method

some small losses in the edge of the break. The vase by Piló was poorly glued and in it was necessary to detach the fragments. This was achieved by applying a cotton patch with acetone in the joint and to cover the vase with plastic for a few minutes. The fragments were then cleaned and glued with a Paraloid B72 in acetone (50% w/v). The Cargaleiro vase used the same bonding materials but due to the number of fragments it was a systematic work that consisted in attaching two fragments at a time with a few hours gap between each step. (Figure 5)

Figure 5. a) b) Vase before restoration; c) Vase after restoration. No filling or retouching was made in the interior of the vase; d) e) f) g) Vase before, during and after restoration.

The big vase by Palmiro Peixe needed a different approach. Although the interior bottom was covered with cement it didn’t adhered to the porcelain. The problem was how to reach the lower inside area of the vase. The solution was to attach a small chisel to a wood stick that carefully allowed to remove the cement and detach the fragments. After the cleaning of the fragments the pieces were joined by phases and temporarily reinforced with a plastic

sheet for 24 hours, preventing the fragments from dislocating. Due to the size and weight of the object it was necessary to use a stronger adhesive. An epoxy resin – EPO 121 - with a filler – fumed silica - was then applied in the joint areas. Although the epoxy is a very resistant and non-removal adhesive, its bonding degree was lowered by the introduction of a filler [3] [4] [5]. After bonding, the joints and the lacunas of the vases were filled. The fillings were limited to the exterior lacunas and break edges but only in selected areas in order to diminish the visual disruption caused by the breaking lines. The main goals were to interrupt the more noticeable joints limiting the intervention to a minimum, making the intervention recognizable and stopping the interferences that distracted the reading of the objects as a whole. In proportion the big Palmiro Peixe vase endorsed a less extensive area of fillings. The profusion of decoration, its colours and dimension camouflaged the joint lines. The three vases, although different in dimension and in the extent of the lacuna, were filled using an epoxy resin – Milliput – sanded down to size and then retouched.

2.3. Retouching

The retouching was limited to the filled areas and the same minimum intervention principle was applied. The combination of these criteria with the nature of the material – recent porcelain, with a uniform, flawless and extensive monochromatic glazed surface – pointed to a mimetic retouch. This characteristics were also decisive in the selection of the materials and techniques - airbrush retouching process.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

29


III. Perspectives on the restoration of porcelain - selecting the retouching method

the losses of the background, particularly the interference caused by the joint lines. The application of the Gestalt psychology and its Perceptual Organization Laws in the interpretation and treatment of losses, provides a solid theoretical background [8]. Although its application is mainly related to discernible retouching, it is possible to take it in account in this particular case where a combined approach was considered: mimetic retouching with discernible areas of intervention. The selection of the retouching method was the most debated aspect. The final hypothesis varied between the use of a coloured filling Figure 6. a) b) c) d) Vase before restoration; e) Retouching with airbrush; f) Vase after restoration. No filling or retouching was made in the figures.

3. RESULTS and Discussion 3.1. Selecting the retouching method

The symbolic value of an object must be taken into consideration when deciding how to restore, since one of several interpretations is privileged in detriment of another [6]. In this case it was decided not to fill or retouch the figures in the vases, only the large and plain areas, considered more visual disrupting than the images - following the principles applied by Cesare Brandi and the dichotomy figurebackground in a reverse concept [7]. In this case, although the figures – geometrical, floral or figurative – represent the core of the objects, the viewer’s eye were immediately attracted to

30

material [9] [10] and the use of airbrush. The key feature for the decision was the fact that majority of the work have a plain and smooth background, ideal for airbrush retouching - merging the filling material with the surrounding area. The airbrush technique was complemented with paintbrush retouching when necessary. The use of airbrush allows a subtle application of colour, particularly in the case of larger, plain, smooth and glazed areas. In some cases details were also retouched with paintbrush over the airbrushed areas.

3.2. Applying the selected retouching method

Mimetic airbrush retouch was particularly successful for the Piló and Cargaleiro vases. Both presented extensive lines of fracture covering the surface and occasionally crossing the decorative motives. In both cases it was decided not to fill the decorative motifs which represent the smallest polychromed areas (Figures 5g and 6d). Although the decoration is stylized and minimalist which should attract


III. Perspectives on the restoration of porcelain - selecting the retouching method

the viewer’s eye, it was the plain background that posed as a distracting factor.

4. CONCLusions

Opposite to this two vases the big Palmiro Peixe vase, was paintbrush retouched. The profusion of decorative motives concealed the lacuna and the joints. Selected areas were filled particularly those who presented gaps in the bonded fragments. Since the decoration is hand-painted the different colour effects were easier to replicate using a brush.

The main goal of this intervention was to address the process in a critical way. The challenge was to find a solution that could integrate an ethical approach, the museological narrative and the viewer’s needs. Even though the visitors should be taken in consideration this

The vases were not filled or retouched in the inside, making it easy to identify the restored areas. The other restored objects, such as the sculptures, followed the same principles applied to the vases, but in a smaller extension. The inside of the sculptures was also not restored in order to allow a clear identification. As mentioned by Heinz Althofer, it’s the work of art that determines the conservation treatment [11], however the theoretical principles that support a conservation and restoration intervention are also bounded to other factors. Historical, artistic or economical aspects are always present in the decision making process. The public is also an important part of the equation - although not a decisive factor it should not be underestimated. Ultimately the objects are there for the public to appreciate and to learn from them.

aspect should not be imposed over the other aspects of the intervention. In addition, the fact that the Museum integrate a heterogeneous scope of production dates – from the 19th to the 21st century -, with classical and contemporary works, with different typologies and authorships, current and limited editions, posed as a challenge in the definition of the methodological approach to the work. The option of not filling or retouching the inside of the vases, allows not only a clear distinction between the restored and unrestored areas but also promotes a didactic approach to the object. The visitor can see the object as a whole, but in a closer and more attentive observation can clearly identify the restoration following the bonding joints. The decorative motives of the vases, although not restored, don’t pose as a distracting factor. The lines that cross the decoration are minimum. The use of mimetic airbrush retouching presented itself as the most effective approach for most of the objects and was often combined with paintbrush retouch. The material, surface and decorative characteristics along with the type of damage, conditioned the retouching technique and method.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

31


III. Perspectives on the restoration of porcelain - selecting the retouching method

REFERences [1] HENRIQUES, Paulo – “Ciclos de Modernidade” in Cerâmica Portuguesa do Século XVI ao século XX. Lisboa: Fac-Simile, 2004, pp. 160-161. [2] MACEDO, Borges de, ‘Introdução Histórica a um Inventario Artístico’ in Vista Alegre Porcelanas. Lisboa: Inapa, 1989, p. 29. [3] OAKLEY, Victoria; JAIN, Kamal K. Essentials in the care and conservation of historical ceramics objects. London: Archetype Publications, 2002. [4] WILLIAMS, Nigel. Porcelain Repair and Restoration. London: British Museum, 2002. [5] BUYS, Susana, OAKLEY, Victoria. The conservation and Restoration of ceramics. London, Butterworth, Heinemann, 1993. [6] MUÑOZ VIÑAS, Salvador. Teoría contemporánea de la Restauración. Madrid: Editorial Síntesis, 2003, pp.115-117. [7] BRANDI, Cesare. Teoria do Restauro. Amadora: Edições Orion, 2006, pp.13-27, 85-90. [8] BAILÃO, Ana - O gestaltismo aplicado à reintegração cromática de pintura de cavalete. ECR – Estudos de Conservação e Restauro. Nº1 (2009), pp. 128-139. [9] Royal Collection Trust: Restoring Porcelain, Part 4. Available at: https://www.youtube.com/watch?v=CUllVUC 3HKk [15 February 2016]. [10] Royal Collection Trust: Restoring Porcelain, Part 5. Available at: https://www.youtube.com/watch?v=je5-OCJGY5M [15 February 2016]. [11] ALTHOFER, Heinz. La questione del ritocco nel restauro pittorico. Padova: Il Prato, 2002, p.45.

32


IV

Crowd funded Research: Low-cost Multispectral Imaging


IV.

Crowd funded Research: Low-cost Multispectral Imaging

Antonino Cosentino (1) (1) CHSOS, Cultural Heritage Science Open Source; Aci Sant’Antonio, Italy; chsopensource.org antoninocose@gmail.com

Abstract This paper introduces the low-cost multispectral imaging (MSI) system for Art and Archaeology recently developed by Cultural Heritage Science Open Source (CHSOS) thanks to the first crowdfunding campaign in Conservation Science. CHSOS develops and disseminates affordable methodologies for art examination in order to reach a large audience of cultural institutions and art conservation professionals interested in introducing scientific diagnostics into their workflow. CHSOS disseminates these solutions with its popular blog, open access publications and training programs. The system is composed of a digital camera with the infrared cut-off filter removed and extended sensitivity to about 360-1100 nm. A set of 18 bandpass filters (representing the spectral features of the most common historical pigments in the 400-925 nm range) provides the spectral images to build up the reflectance imaging cube. The system was tested successfully on Pigments Checker, a collection of historical pigments, and on a mock-up painting for pigments’ preliminary identification and their mapping.

Keywords Multispectral Imaging; Pigments; Pigments identification; Pigments mapping; Pigments Checker.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

35


iv. Perspectives on the restoration of porcelain - selecting the retouching method

1. Introduction Cultural heritage scientists use a large number of imaging and spectroscopy techniques to examine works of art and archaeology. Often, sampling is not permitted and noninvasive and non-destructive spectroscopic methods are preferred, Imaging methods are largely preferred since they do not require any sampling. Technical photography [1], infrared reflectography [2], reflectance transformation imaging (RTI) [3], and Multispectral Imaging (MSI) [4, 5] are among the most used imaging techniques. MSI is used to map and identify pigments [6], to localize inpaints [7] and to enhance the reading of faded documents. While reflectance spectroscopy [8] provides spectra of pigments for a single point, MSI allows to reconstruct spectra from each image’s pixel and consequently to remotely identify and mapping pigments. An MSI documentation of a painting consists in the acquisition of a series of spectral images, which are necessary to create a reflectance image cube: pixels of each image are represented in the X and Y axes while the wavelength of each spectral image is reported in the Z axis. From this cube is then possible to reconstruct the reflectance spectrum for each image’s pixel. MSI equipment is commonly composed of a monochromatic camera: a CCD camera [911] for the UV-VIS-NIR range or a much more expensive InGaAs camera for the SWIR (900– 2500 nm) range [12, 13]. Some studies also employed a commercial colour digital camera [14, 15]. In general, the reflectance spectral 36

features in the UV-VIS-NIR range are due to the electronic transitions responsible in part for the colour of the pigments, while those in the SWIR range are linked to the vibrational overtones. A wavelength selection system is added to the camera so that it can capture images of an object in a series of spectral bands. This paper presents a new low-cost system using a digital camera, 18 bandpass filters and in-scene calibration card. The system is designed to have sufficient accuracy to be used in art diagnostic studies, to be affordable (it uses free software) and versatile so that it can be modified or upgraded for MSI documentation of different kind of Art and Archaeology. This system was recently developed by CHSOS (Cultural Heritage Science Open Source) thanks to the first crowdfunding campaign in Conservation Science: “Multispectral Imaging (MSI) for Art and Archaeology”, Figure 1. The project was funded by 43 donors from 16 Countries. Micro funding came directly from professionals in the art conservation sector to develop an affordable MSI system.


iv. Perspectives on the restoration of porcelain - selecting the retouching method

Scientific examination and documentation of art is notoriously expensive. The most important and recognizable works of art from prestigious museums are often subjected to extensive scientific studies, unfeasible forthe vast majority of cultural heritage objects, existing in local communities simply because they lack comparable financial resources.

Figure 1. Multispectral Imaging for Art and Archaeology was a successful crowdfunding campaign launched on Indiegogo.

CHSOS develops and disseminates each year an affordable version of a scientific tool for art examination and documentation, Figure 2. CHSOS promoted Technical Photography in 2013 [1], an affordable Infrared Reflectography system in 2014 [2] and the low-cost Multispectral Imaging system discussed in this paper in 2015.

Typically larger museums have budgets sufficient for scientific departments equipped with cutting-edge technologies.In contrast, small to medium sized cultural institutions have relatively limited access to the same science and technology. CHSOS wants to bridge this technological divide, developing and disseminating affordable and sustainable methodologies for art examination.This search for low-cost methods is becoming a rapidly expanding research topic with a growing number of researchers exploring affordable technical solutions for their workflow in art examination.

2. Materials and methods 2.1. MSI system components

Figure 2. CHSOS Mission. Disseminate innovative, affordable and sustainable Technologies for Art examination.

The system is composed of a digital camera (Nikon D800) modified to be sensitive to approximately 360-1100 nm range by removing the inside IR-blocking filter, Figure 3. It was chosen to use a digital camera, rather than a monochromatic camera so that the same camera could also be used for other imaging methods, such as technical photography, RTI and photogrammetry, making the overall imaging equipment compact, and versatile.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

37


iv. Perspectives on the restoration of porcelain - selecting the retouching method

The system uses a set of (1 inch dimeter) 18 bandpass filters (bandwidth 10 nm) covering the 400-925 nm range, (center wavelength, nm): 405, 430, 450, 467, 480, 500, 532, 560, 580, 610, 640, 671, 700, 730, 760, 840, 860, 920. The filters’ center wavelengths represent the spectral features (absorption or inflection points) of the most common historical pigments, table 1. The filters are held on the photographic lens with a 3D printed filters adapter, Figure 3.

Figure 3. MSI system components. A) Full spectrum modified DSLR camera. B) 18 bandpass filters set. C) Filters adapter. D. In-scene calibration card.

Table 1. 18 filters’ center wavelengths and corresponding pigments’ spectral features. Center Wavelength (nm)

Spectral features

405

Titanium white absorption; chrome green maximum

430

Smalt, malachite maxima

450

Prussian blue maximum, massicot inflection

467

Phthalo blue maximum (465), lead tin yellow I (465) inflection

480

Cadmium yellow inflection

500

Verdigris, phthalo green maxima; yellow lake R. (490) inflection

532

Cobalt blue inflection; cobalt green maximum; orpiment, lead tin yellow II (525), naples yellow (515), gamboge (535) and saffron inflections

560

Realgar inflection

580

Red lead (575) inflection

610

Cobalt yellow absorption (615); ochre (600) maxima, vermilion, cadmium red, alizarin, madder lake inflection

640

Ochre (645) minimum; carmine lake (630) inflection

671

Lithopone absorption (670)

700

Cobalt violet maximum

730

Lithopone absorption (725)

760

Maya blue, viridian (770) inflections; ochre (770) maximum

840

Indigo inflection (830)

860

Ochre minimum

920

Phthalo blue, ochre (915) minima

The system works with a an in-scene calibration card to cover the 400-925 nm spectral range with 6 swatches, pure white, 4 grays and pure black (reflectance values (%): 100, 80, 60, 40, 20, 0,5). The system is designed to work with any visible and infrared illumination source, such as halogen lamps. (the examples shown in this paper were produced using halogen lamps (2 x 400 W).

38


iv. Perspectives on the restoration of porcelain - selecting the retouching method

2.2. Software editing

The Nikon D800 features a Full Frame FX format CMOS sensor whose photosensors are covered with color filters to select only red (R) green (G) or blue (B) light. Photos are shot in raw format and are then split into their 4 color (BGRG) components using ImageJ. 18 images are selected among the split RGB images in order to build up the reflectance cube with HyperCube (US Army Geospatial Center) imaging spectroscopy software. They are selected among the B channel in the range 400-480, G for 500-560 and R for 580-920. Registration and flat field correction are both performed within ImageJ. The reflectance calibration of the spectral images is performed using the in-scene calibration card and applying a multi-point 3rd degree polynomial calibration curve with ImageJ.

3. RESULTS and Discussion 3.1. Reflectance spectra reconstruction

Pigments Checker is a collection of 54 swatches of historical pigments applied using gum arabic as a binder on cellulose and cotton watercolor paper, acids and lignin free, Figure 4.

Figure 4. Reflectance Pigments Checker.

spectra

reconstruction

on

The system has been tested on Pigments checker to evaluate its accuracy in reconstructing reflectance spectra. 18 spectral images have been acquired and edited to build the reflectance spectral cube. Figure 4 shows the reconstructed spectra of yellow ochre and chrome green and compares them with reference reflectance spectra of the two pigments also acquired on the same Pigments Checker [8]. The main features of the pigments are represented. Yellow ochre has two absorption bands at about 645 nm and 860 nm while chrome green has absorption bands at 460 nm and 600 nm.

3.2. Mapping pigments

The system was also tested on a mock-up oil painting on canvas “Madonna and Child�, representing a subject in the renaissance style. The painting was created using renaissance age pigments (mineral ultramarine, azurite, yellow ochre, red ochre, lead white, verdigris, III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

39


iv. Perspectives on the restoration of porcelain - selecting the retouching method

vine black and malachite) as well as modern pigments (viridian, titanium white and cadmium red), Figure 5. The system was tested successfully on this painting to evaluate its capacity to map pigments (segmentation).

REFERences [1] COSENTINO,

Antonino – Identification of pigments by multispectral imaging a flowchart method. Heritage Science, 2:8, (2014).

[2] COSENTINO, Antonino –Panoramic infrared Reflectography. Technical Recommendations. Intl Journal of Conservation Science, 5(1), (2014), pp. 51–60. [3

COSENTINO, Antonino – Macro Photography for Reflectance Transformation Imaging: A Practical Guide to the Highlights Method. e-conservation Journal, 1, (2013), pp. 70-85.

[4] COSENTINO, Antonino – Multispectral imaging system using 12 interference filters for mapping pigments. Conservar Património 21, (2015), pp. 25-38. [5] COSENTINO, Antonino – Multispectral Imaging of Pigments with a digital camera and 12 interferential filters. e-Preservation Science, 12, (2015), 1-7. [6] KUBIK, Maria – Hyperspectral imaging: a new technique for the non-invasive study of artworks. In Creagh, D C and Bradley, D, eds – Physical Techniques in the Study of Art, Archaeology and Cultural Heritage, Vol. 2. Elsevier, 2007, pp. 199–259.

Figure 5. Mapping pigments.

4. CONCLusions CHSOS assembled a low-cost, simple and versatile Multispectral Imaging system composed only of standard “off-the-shelf” commercially available components: bandpass filters and a digital camera. It can be used to perform MSI documentation for works of art and archaeology for preliminary pigments identification and their mapping.

[7] COSENTINO, Antonino – Panoramic, Macro and Micro Multispectral Imaging: An Affordable System for Mapping Pigments on Artworks. Journal of Conservation and Museum Studies, 13(1): 6, (2015), pp. 1–17. [8] COSENTINO, Antonino – FORS spectral database of historical pigments in different binders. e-conservationJournal 2, (2014), pp. 57–68. [9] LIANG, Haida – Advances in multispectral and hyperspectral imaging for archaeology and art conservation. Appl Phys A, 106, (2012), pp. 309–323. [10] PELAGOTTI, Anna; DEL MASTIO, Andrea; DE ROSA, Alessia; PIVA, Alessandro – Multispectral Imaging of Paintings.A way to material identification. IEEE Signal Processing Magazine 27, (2008), pp 27-36. [11] TOQUE, Jay Arre; SAKATOKU, Yuji; IDE-EKTESSABI, Ari – Pigment identification by analytical imaging using multispectral imaging. 16th IEEE International Conference on Image Processing (ICIP), (2009), pp. 2861–2864. [12] RICCIARDI, Paola; DELANEY, John; GLINSMAN, Lisha; THOURY, Mathieu; FACINI, Michelle; RENE DE LA RIE, E – Use of visible and infrared reflectance and luminescence imaging spectroscopy to study illuminated manuscripts: pigment identification and visualization of underdrawings. O3A: Optics for Arts, Architecture, and Archaeology II, Proc. of SPIE Pezzati, L and Salimbeni, R eds. (2009), 7391. [13] DOOLEY, Kathryn;LOMAX, Suzanne; ZEIBEL, Jason; MILIANI, Costanza; RICCIARDI, Paola; HOENIGSWALD, Ann; LOEW, Loew, Murray; DELANEY, John – Mapping of egg yolk and animal skin glue paint binders in Early Renaissance paintings using near infrared reflectance imaging spectroscopy. Analyst, 138: (2013), pp. 4838–4848.

40


iv. Perspectives on the restoration of porcelain - selecting the retouching method [14] BLAZEK, Jan; SOUKUP, Jindrich; ZITOVA, Barbara; FLUSSER, Jan; TICHY, Thomas; HRADILOVA, Janka –Low-cost mobile system for multispectral cultural heritage data acquisition. Digital Heritage International Congress, IEEE, (2013), pp 73-79. [15] ZHAO, Yonghui; BERNS, Roy; TAPLIN, Lawrence; CODDINGTON, James – An Investigation of Multispectral Imaging for the Mapping of Pigments in Paintings. Proc. SPIE 6810, Computer Image Analysis in the Study of Art, (2008).

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

41


42


V

USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE


V.

USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

Barbka Gosar Hirci (1), Lucija Močnik Ramovš (2) (1) Affiliation 2; Institute for the Protection of Cultural Heritage, Restoration Centre, Poljanska 40, 1000 Ljubljana - SI; E-mail address: barbka.hirci@rescen.si (2) Affiliation 1; University of Ljubljana, Academy of Fine Arts and Design, Erjavčeva 23, 1000 Ljubljana-SI; E-mail address: barbka.hirci@rescen.si; lucija.mocnikramovs@aluo.uni-lj.si

Abstract Nowadays, conservators/restorers rarely use natural resins such as damar or mastics and oil binders for retouching oil paintings. When selecting retouching paints, the principle of using stable materials is of utmost importance and, for this reason, traditional retouching materials are replaced with more stable materials. In our contribution we will compare the practical uses of retouching paints based on two basically different, yet stable, resins: a natural resin, i.e., Canada balsam, and a synthetic resin, i.e., Laropal® A 81. The paints based on the Canada balsam have to be prepared by the restorers themselves, while the paints based on the Laropal® A 81 synthetic resin have been available on the market for a good 10 years under the brand name Gamblin Conservation Colours. The literature and the manufacturers’ instructions provide us with a lot of recommendations for their use, which need to be tested and upgraded in practice. This paper discusses a comparison between the properties of these binders, the methods of paints preparation and the methodologies of their use. It addresses, in detail, the issues of selecting the appropriate solvent mixture, the maintenance of the appropriate gloss of the coatings, the dilemmas when applying the isolating and finishing varnishes, and the actual applicability of the paints. The frequent use of a certain material often leads the conservator-restorer to a solution that may be in opposition to the manufacturers’ instructions. How do we solve such a problem?

Keywords Gamblin Conservation Colours; Canada balsam; Retouching; Underpainting; Solvent; Varnish.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

45


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

1. Introduction When discussing the retouching of damage to oil paintings, the binder is one of the basic elements. Technologies vary in the amount of drying oils, pigments, colour layers and various additives. All of these influence the saturation level of a paint layer, giving it a dull, matt or glossy appearance. The majority of “traditional” oil paintings very often also include the final varnish. The material used for retouching has to be compatible with the original and with any previous conservation/ restoration interventions. Here we have to pay attention to the texture, transparency and gloss of the original paint layer. When deciding on the appropriate binder and pigments, we need to consider a few basic criteria: the compatibility with the original, the reversibility, the ease of the procedure, the safety during use and the stability. [1] The stability of the material, in particular, is of key importance when choosing the appropriate resin, as yellowing is one of the main reasons why synthetic binders have replaced traditional, natural ones (oil paints). The binder has to be soluble in solvents of low and medium polarity, thus providing more flexibility for the restorer. Here, the possibility of wetting the paints and their workability need to be considered. The evaporation time of the solvent influences the application of the paint and its drying time: from the point of taking the paint from the palette to applying it on the picture. The solvent also allows us to modify the glossiness. Using rapidly evaporating solvents of high polarity, we can make sharper brush strokes, create a matt appearance for the applied paint, and as the paint dries up

46

quicker, the application must also be made faster. If using slowly evaporating solvents with a low polarity, the brush strokes are softer, the paint takes a longer time to dry, so influencing the levelling, and consequently resulting in a higher glossiness. The characteristic of the film determined by the glass-transition temperature (Tg) is important when selecting the binder for retouching. The paint has to dry up in an appropriate time and the surface has to feel dry and non-sticky when touched [2], especially in the cases when we do not apply the final varnish on the surface of a retouched picture, or when we perform the final retouching on the varnish. Resins have different Tg values, determining the softness of the film. If the temperature of the environment is higher than the Tg of the resin, the film is more susceptible to dust and other particles, and therefore less appropriate for the final application. [3] The refractive index of the resin is also very important when we need to make a correction to a retouch after having applied the final (glossy) varnish. Industrially prepared paints called Gamblin Conservation Colours (henceforth referred as GCCs) made on the basis of the synthetic resin Laropal® A 81 and the paint based on the natural resin Canada balsam (henceforth referred to as CB) that restorers can make by themselves, fulfil the above requirements. Their properties will be discussed in the sections below.


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

2. MATERIALS AND METHODS 2.1. Properties of resins Canada balsam and Laropal® A 81

CB is an oleoresin (a mixture of oleoresin acid and essential oils), obtained from the Canadian fir tree called Abies Balsamea. It contains about 25% of the essential oil, and it is soluble mostly in polar solvents [4]. The use of CB as a binder for retouching paints is not widespread. Its introduction and use in the preparation of retouching paints are due to its viscosity and a reduced rate of yellowing. The methodology for preparing paints and the experiences with its application were presented to us by Stefano Scarpelli, an Italian restorer. [5] We have been using it for retouching oil paintings since 2006. When essential oils evaporate from CB, it turns into a transparent, slightly yellow substance. The optical properties of CB are almost identical to those of glass (from 1.518 to 1.529). After having been stored for more than a hundred years, the slides coated with CB were completely intact. For this reason, it was used in optics for attaching samples onto microscope slides and for gluing together pieces of glass. [6] Our preliminary measurements show that Tg ranges between 54 and 56°C; however, additional experiments are required to confirm these results. [7] Due to its viscosity, which allows dispersing of the pigment, and its exceptional optical properties that do not change with aging, it was found to be a suitable binder for retouching paints. Industrially prepared GCC are based on a photochemically stable urea-aldehyde resin – Laropal A® 81 made by BASF – dissolved in a mixture of petroleum distillate. Laropal® A

81 belongs to the group of resins with a low molecular weight, whose optical properties are similar to those of natural resins. It dissolves in hydrocarbons with at least a 25% share of aromatic content and remains soluble in solvents with a low polarity. The refractive index of this resin is 1.50, while its Tg is about 57°C. [8]

2.2. Preparation and use of Gamblin Conservation Colours

As these paints contain a solvent it should be emphasised that there is no best way of storing the paints, which is also clearly indicated by the manufacturer. [9] Prior to their use, we need to stir the paints well so that the binder is evenly distributed, then we can start taking the paint out of the jar. This procedure is not very easy. The other possibility is to take the paint from the bottom of the jar, which means that the substance we take out is less saturated. For greater efficiency and easier work, it is recommended to wait until the colour on the palette dries (the solvent evaporates). Paints can be used to retouch a picture with matt or glossy techniques. In line with the tests made in different museums, the manufacturer recommends the use of different solvents or solvent mixtures, with which to dissolve colours, e.g., Ligroin, Shellsol TS-28 and isopropanol in the ratio 1:1:1, isopropanol and aliphatic hydrocarbon with a 15% aromatic content in the ratio 1:4, pure isopropanol or pure 1-methoxy-2-propanol. The selection of the solvent greatly affects the spreadability and the method of wetting

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

47


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

different paints or pigments. The solvent mixtures of isopropanol and mineral spirit (Shellsol D-40 or Shellsol A) that we used allowed a slightly longer treatment of paint on the palette, but also made it difficult to achieve a uniform dissolution, i.e., the uniform spreadability of paint. [10] When we only used mineral spirit (Shellsol A), the drying time was as long as expected and the lines made with the brush were soft. The amount of the colour at the top of a brush has to be checked to prevent the colour from swelling at the end of a stroke. Ethyl lactate that we used is comparable with petroleum-based solvents. It has a low surface tension and a slightly lower boiling point (154°C), allowing a uniform spreadability of the paint and its treatment on the palette (figure 1). [11]

homogeneous mixture (figure 2). We can add a few drops of acetone to improve the quality of the mixing. The ratio of the binder and the pigment affects the transparency of the paints. A problem arises when there is too much binder. In such a case the paint does not attach well, the colour tone is very weak and the applied layer does not dry. Based on our experiences, a porcelain palette with a lid, which is also a handy surface for mixing paints, is very useful. We apply thin, translucent layers of the prepared paints. The final retouching has to be done with the fewest possible layers, making sure that the retouch does not become too saturated. If the colour tones do become too saturated, the retouched images appear to be heavy and become increasingly prone to yellowing over the years. Individual translucent layers should be completely dry before we continue our work. This drying usually takes one day. We dissolve the paints to be applied with butyl alcohol or ethyl lactate. If the retouching does not match the gloss of the painting, a few drops of the varnish, with which we varnished the picture for the first time, should be added to the medium.

Figure 1. Testing different solvents with GCC.

2.3. Preparation and use of retouching paints on the basis of Canada balsam

We make the paints on the basis of CB by ourselves using high-quality pigments that need to be well ground. An approximate ratio of 1/3 pigment and 2/3 binder is used. The proportion varies depending on the absorbency of the pigments. We mix the pigment and the binder with a spatula until we achieve a thick, 48

Figure 2. Preparation of retouching paints on the basis of Canada balsam

2.4. Construction of a retouch

In most cases, we perform the retouching in


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

two basic phases. The first phase includes the monochromatic application of the primary layer of retouching, covering the previously filled-in areas. For the primary layer of retouching, we normally use high-quality gouache colours. They allow us to imitate not only the colour but also the structure of the paint layer. The primary layer of retouching is done in brighter and slightly colder colour tones. The suitability of the selected tones is controlled with a cotton swab, soaked in a white spirit. In most cases, we finish the primary level with the interim varnishing of the picture. This methodology is the basis for the subsequent retouching, for which we use the paints based on resin binders (figure 3).

Figure 3. Construction of a retouch with CB (monochromatic application of gouache colours, varnish and retouch), Pietro Liberi, St Nicolas, detail, 17th century, oil and tempera on canvas, 392 × 215 cm.

method for their application is spraying with a spray gun. To establish the compatibility of the final varnish with the paints based on GCCs we performed simple tests. The reason was the fact that on certain oil paintings the retouches made by GCC “disappeared” when we used the final varnish based on Laropal A 81 and Shellsol A. Three laminated canvases with dimensions of 30 × 40 cm, coated with a black gouache colour were used. On two canvases (Samples 1 and 2) we applied two layers of the Laropal A81 (20 g of resin in 100 ml of Shellsol A). On the third canvas (Sample 3) we applied two layers of the Regalrez 1094 varnish (20 g of resin in 100 ml of Shellsola D 40). After 12 days, we applied GCCs on the varnished surfaces, using the tratteggio technique. To dilute the paints we used pure ethyl lactate and the Galdehyde Resin medium mixed with ethyl lactate in the ratio 1:1. [12] We applied similar colour variations on all the samples. We used two different media for diluting the paints because we wished to check the stability of the translucent layers with a higher proportion of the resin. We applied the final layer of varnish about 30 days after the previous varnishing. We used the same varnishes as for the isolating varnishing, applying them in different ways (with a brush or a sprayer).

2.5. Use of final varnishes

The composition of the final varnish and the method of its application depend on the type of the isolating varnish and the solubility of the retouching paints. The varnishes prepared from a100-percent aromatic solvent and including at least a 15-percent share of aromatics cannot be applied manually as we would, in this way, dissolve the retouch. A more appropriate

3. RESULTS and Discussion 3.1. Compatibility with the varnishes

We applied the final varnish Regalrez 1094 on Sample 1. On one side of the sample, we applied the varnish with a brush, and on the

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

49


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

other side, we applied it with a sprayer from a distance of about 20 cm. The varnish did not dilute the retouch on any of the sides; even when using the brush, we did not remove the retouch (figure 4). On Sample 2, we applied the final varnish Laropal A 81 using a sprayer from a distance of about 20 cm. After application, we noticed changes made to the retouch: the paint layers were partly deleted; the paint lines began to smear, especially in the places where we used the solvent and the Galdehyde Resin medium (1:1) for the paint application (figure 5). On Sample 3, with an isolating layer of varnish Regalrez 1094, we applied the following with a sprayer at a distance of about 30 cm: varnish Laropal A 81 on the left-hand side and varnish Regalrez 1094 on the right-hand side. After the application of the final layer of Laropal A 81, we noticed a difference between the retouch for which we used pure solvent and the retouch that we realised with the medium. (figure 6). On the latter, we could see the smearing of the colours. On the right-hand side the sample, there were no noticeable changes in the retouched areas. The tests showed that a retouch may be removed in the cases when, for the final varnishing, we use varnishes based on highly aromatic solvents, even if we apply them by spraying. As the application of the final layer based on the Regalrez 1094 resin does not cause the dissolution of the paints, and the solvents Shellsol D 40 and Shellsol A have about the same boiling point, the reasons for the smudging of the paints after the application of the final layer (Laropal A 81) may be a high fraction of aromatics in the Shellsol A (97%) and the distance between the painting and the

50

position, from which we apply the varnish.

Figure 4. Sample 1: after application of the finishing varnish made of Regalrez 1094 (on the left side with a brush, on the right side with a sprayer).

Figure 5. Sample 2: after application of the finishing varnish Laropal A 81 with a sprayer (left is the retouch that we realised with the medium).

Figure 6. Sample 3: after application of the finishing varnish Laropal A 81 with a sprayer (left is the retouch for which we used pure solvent, right is the retouch that we realised with the medium).

3.2. Comparison of the binders with respect to practical use

The paints based on CB require careful preparation. The grinding of the pigments


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

is of key importance. It is difficult to monitor and control the additions of binders. The quality of the prepared paints can only be tested after they dry on the palette. If we fail to appropriately prepare paint or if we run out of it, we have to start the process again. GCCs are industrially ground. The amounts of the binder and pigments are precisely determined. If we run out of paint on the palette, we can just take more of it from the little jar. To apply the paints based on CB, we mostly use polar solvents. When using butanol, the paints dissolve quickly and the application takes a longer time. The disadvantage of butanol is that it is extremely unpleasant to use. We can replace it with some other solvent, e.g., ethyl lactate, but then the paints dissolve more slowly. GCCs can be used with a wide range of solvent mixtures. We select them on the basis of the gloss of the original surface. When applying the CB-based paints, individual colour layers have to be dry before we can proceed with our work. These paints are very translucent and never provide complete opacity. If we work too fast, the previous layer is likely to dissolve, making our work difficult and impossible to be carried out at the required quality level. In the case when we wish to saturate the surface as required by the original, we have to apply the paints in several layers that have to dry completely each time. On the other hand, the retouching with GCCs is simple. Even though we use the same solvent, the previous colour layers do not dissolve. We can use GCCs as translucent colours or fully opaque colours. We can create a full opacity with one tone, which is very difficult to do with the CB-based paints.

In the case of the CB-based paints, we create gloss during or after the retouching by locally varnishing the retouched area. The disadvantage of the method of adding varnish to the paints during the retouching is that the colours become even more translucent than before this addition. In the case of GCCs we can modify the gloss with the solvent for diluting, which is a great advantage. Here we need slightly more time for analysing and testing, but the efforts pay off in the end. The other possibility is to modify the gloss with a resin medium that we can prepare by ourselves or buy as a ready-made version (Galdehyde Resin medium).

4. CONCLusions A comparison of different binders with respect to their practical use is only possible after the extended use of these binders. Knowing about the properties of binders that determine the stability of paint is of key importance when selecting the material for retouching. In our work we need to take note that new, more stable materials are entering the market, replacing the current ones. When comparing the two binders, we can find crucial differences already between their preparation procedures and also in application.The preparation of the CB paints requires a lot of time, especially the preparation of certain pigments, which can be the reason for their less frequent use. For the dilution of the GCCs, we also use ethyl lactate. Due to the above-mentioned properties, this solvent proved to be very suitable; moreover, it is also biodegradable

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

51


V. USE OF RETOUCHING COLOURS BASED ON RESIN BINDERS – FROM THEORY INTO PRACTICE

and non-toxic. As we use a resin binder, we need to consider the type and method of applying the final varnishes. When applying the varnishes based on the Laropal A 81 resin and the solvents with a high fraction of aromatics, we found that the stability of the GCCs was problematic. We noticed occurrences of paint dissolution. By performing the tests, we wanted to check the influence of this type of varnish on the lower layers. The tests showed that a varnish with an aromatic fraction (97%) applied by spraying can lead to the dissolution of a retouch made with GCCs. We must point out that, in future, to obtain clear results, it will be necessary to further test the solvents with various aromatic fractions, considering the minimum amount of aromatics necessary for the Laropal A81 resin to dissolve, as well as the distance from which we apply the varnish, etc.

REFERences [1] HORIE, Velson – Materials for Conservation. Organic consolidants, adhesives and coatings. Boston [etc.]: Butterworth-Heinemann: Elsevier, 2010, pp. 4. [2] HORIE, Velson – Materials for Conservation. Organic consolidants, adhesives and coatings. Boston [etc.]: Butterworth-Heinemann: Elsevier, 2010, pp. 248. [3] SCHILLING, Michael. R – The glass transition of materials used in conservation. Studies in conservation. Vol. 34, n.º 3 (1989), pp. 110-116, 111. [4] Canada Balsam. Details (PDF). Available at: http://www. kremer-pigmente.com/media/files_public/62110e.pdf [1 September 2015]. [5] MOČNIK RAMOVŠ, Lucija; GOSAR HIRCI, Barbara – Retouching: How and with What? International Workshop on Retouching Oil Paintings and Wooden Polychrome Sculpture. Journal for the protection of Monuments. Vol. 44, (2008), pp. 202-207. [6] ALLINGTON, L., SHERLOCK, E. – Choosing a Microscope Slide Sealant: A Review Of Aging Characteristics And The Development Of A New Test, Using Low Oxygen Environments. NatSCA News, Issue 12, 4 14. Available at: http://www.natsca.org/sites/default/files/ publications/NatSCA%20News%20Issue%2012-2.pdf [14 February 2015]. [7] The experiment was carried out in a 20-ml Al crucible, the DCS was recorded in module DSC1/778/700, the heating rate was 5°C/min. [8] DE LA RIE, E. René; QUILLEN, Lomax, Suzanne; PALMER, Michael; DEMING GLINSMAN, Lisha; MAINES, Christopher A ­– An investigation of the photochemical stability of ureaaldehyde resin retouching paints: removability tests and colour spectroscopy. In Conference Paper, Tradition and innovation: advances in conservation: contributions to the Melbourne Congress, 10-14 October, 2000, pp. 51 - 59. [9

LEONARD, Marc; WHITTEN, Jill, GAMBLIN, Robert; DE LA RIE, E. René ­– Development of a new material for retouching. In Conference Paper, Tradition and innovation: advances in conservation: contributions to the Melbourne Congress, 10-14 October, 2000, pp. 111-113.

[10] Shellsol A. Shellsol D-40.Material Safety Data Sheet (PDF). Available at: http://www.kremer-pigmente.com/ [14 February 2015] [11] Ethyl lactate. Properties. Available at: http:// www.sigmaaldrich.com/catalog /product / sial/69799?lang=en&region=SI [14 February 2015]. [12] Galdehyde Resin Solution. GAMBLIN Conservation colours (PDF), Material Safety Data Sheet (PDF). Available at: http:// www.kremer-pigmente.com/en/ready-made-colours/ galdehyde-resin-solution-8010015.html [14 February 2015].

52


VI

BRINGING THE REMBRANDT BACK TO LIFE: THE RETOUCHING OF SAUL AND DAVID


VI.

BRINGING THE REMBRANDT BACK TO LIFE:

THE RETOUCHING OF SAUL AND DAVID

Carol Pottasch (1), Susan Smelt (1) (1) (Senior) paintings conservator; Mauritshuis; Plein 29, 2511 CS The Hague; E-mail address: c.pottasch@mauritshuis.nl; s.smelt@maurtishuis.nl.

Abstract Rembrandt’s painting Saul and David, c. 1651-54 and c. 1655-58, has had a turbulent restoration history. Previous interventions have left the painting with a missing top right corner, damaged paint layers that were difficult to interpret, and an unusual vertical join. Possibly in the 19th century, the painting was cut into two separate pieces. These parts were put together again at a later date, and a fragment of another painting, c. 50 x 55 cm, was inserted in the top right corner. A conservation treatment was carried out at the Mauritshuis in 2014-15. A committee of international experts was formed to give advice on the restoration of this complex painting. During the treatment, it was decided that the overpaint should be removed from the non-original pieces of canvas. Then all of the inserts and the white fills were toned with a colour that matched the original ground. This provided a neutral-coloured surface suitable for the subsequent stages of retouching. The main aim of the retouching was to bring it to a stage where an informed visitor inspecting the painting at close proximity could see that some parts of the painting are not original; however, other visitors standing further away would still be able to appreciate and admire it as a painting and a work by Rembrandt. In this paper, the philosophy and the practice of the retouching of the Saul and David by Rembrandt will be described. How were the differences between experimental painting technique and damage assessed? Which retouching materials were used and why? How were the retouching materials applied? This paper will give an insight in the complex process of retouching.

Keywords Rembrandt: Complex retouching: Large insert: Painting technique or damage: Lascaux Water Resoluble Medium: Gamblin Conservation Colors: Retouching philosophy.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

55


VI. BRINGING THE REMBRANDT BACK TO LIFE

1. INTRODUCTION The painting Saul and David, c. 1651-54 and c. 1655-58, by Rembrandt van Rijn (16061669) recently underwent a conservation treatment at the Mauritshuis in The Hague, the Netherlands. Not only has the painting itself been restored, but its glory, honour and dramatic effect on the beholder have also been reinstated. The painting has not only had a turbulent restoration history, but also the attribution to Rembrandt, coinciding with the appreciation for the painting, changed in the course of its history. This paper will focus on a specific part of the challenging treatment of the painting, namely the retouching.

Figure 1. Rembrandt van Rijn, Saul and David, c. 1651-54 and c. 1655-58, oil on canvas, 130 x 164.5 cm, Mauritshuis, inv. no. 621. Before conservation treatment in 2007.

In order to understand the decisions made during the recent treatment, the restoration history of the painting and the complex nature of the painting will briefly be discussed. During the research and treatment, the conservators were supported by an international advisory committee [1]. The committee – consisting

56

of renowned Rembrandt specialists, curators and conservators – was formed because of the complexity and importance of the painting. The materials used during retouching and the way they were applied will be addressed in this paper. Rembrandt’s painting technique needed to be studied to understand the nature of specific damaged areas. This paper will show how all of these challenges were addressed during the complex restoration.

1.1. The restoration history of Saul and David by Rembrandt

The painting was acquired in 1898 by the Mauritshuis director Abraham Bredius (18551946). He bequeathed it to the Mauritshuis after his death. After its acquisition, it was sent to Alois Hauser (1857-1919), a famous restorer in Berlin, for treatment. In the Dutch newspapers of that time, it was stated that he performed an aesthetic treatment: he removed the varnish, applied a new varnish and added some retouchings. This was the last treatment before Petria Noble, at that time Head of Paintings Conservation at the Mauritshuis, started the scientific examination of the painting in 2007. To understand the true condition of the painting prior to the conservation treatment, important questions regarding the original dimensions and the state of preservation (especially the curtain) had to be addressed. Also the attribution of the painting was studied [2]. In 2013, Petria Noble started the treatment. Carol Pottasch and Susan Smelt continued the treatment in 2014 when Petria left to become the head of the paintings conservation studio at the Rijksmuseum. Before its arrival in the Mauritshuis in 1898, the


VI. BRINGING THE REMBRANDT BACK TO LIFE

painting had undergone several restoration treatments, which had affected its format. It had already been noticed in the early 20th century – and again by A.B. de Vries et. al., who also made X-radiographs – that the canvas was composed of many pieces [3]. Probably in the 18th or early 19th century in France, the painting was cut in two. When the figures of Saul and David were later rejoined, a large square above David (which had been lost) was replaced by a ‘new’ piece of canvas. This canvas was clearly cut from an old painting, turned upside-down: it had been part of a 17th century copy after Anthony van Dyck’s Portrait of Isabella Clara Eugenia, Infanta of Spain, shown dressed in the habit of the Poor Clares [4]. The three pieces were assembled using a very unusual notched or crenelated join that is, as far as we know, unique in the history of restoration. Narrow strips were added to the upper, lower and right edges in order to enlarge the picture, and are held in place by the lining canvas. Two small strips under David appear to be original to the painting, but have been displaced. Some other small strips of canvas originate from the aforementioned portrait, (including her fingers, which were placed beneath Saul), and two other pieces of canvas are of unknown origin. After removal of the overpaint, fifteen separate pieces of canvas were revealed. An original horizontal seam runs through both figures of Saul and David, indicating that the two parts of the painting were properly aligned when the pieces were assembled.

Figure 2. Saul and David, after varnish removal and removal of the overpaint on the insert, the added strips of canvas and on the crenulated joins. Photo made by Margareta Svensson.

2. THE CURRENT TREATMENT Before the present treatment, the old varnish layers had discoloured severely, hiding the original colours and texture of the paint. Also, the insert in the top right corner was clearly disfiguring because it bulged forward, and its surface was smoother and shinier than the original. The texture of the overpaint next to the shoulder of David was very prominent and disfiguring. It was decided to remove the overpaint from the insert and all of the added strips of canvas, as well as the overpaint on the crenelated joins. The conservators, curators and director of the Mauritshuis decided to preserve the current format of the painting – along with all of its non-original pieces of canvas – as a testament to its history. The general aim of the treatment was that the later additions to the painting would not be completely “hidden”, but would be visible at close range to an informed visitor.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

57


VI. BRINGING THE REMBRANDT BACK TO LIFE

At the same time, the final result should be aesthetically appealing to the general public.

2.1. The format of the painting

Canvas analysis was undertaken in collaboration with Don Johnson and Rick Johnson at Cornell University to shed light on the original format of the painting. It was discovered that an original unpainted tacking edge was present near the right edge [2]. During a previous treatment, the unpainted tacking margin had been folded out and an extra strip of canvas had been added around the perimeter. David’s proper left shoulder and arm were painted on top of this non-original piece of canvas, proving that they were much later additions, not painted by Rembrandt. After the removal of the disfiguring overpaint on David’s shoulder, it was deemed unethical to completely reconstruct it again. It was therefore decided to build in an addition into the rebate of the frame, which would cover the non-original strips of canvas at the bottom, top and right edge of the painting. The rebate on the right edge of the frame was also enlarged to shift the painting to the right in the frame. This made it possible to cover most of the nonoriginal right edge. In order to not distract the visitor, a compromise was made: David’s red costume (never painted by Rembrandt) was extended at the retouching stage with little red stripes. From a distance, the stripes blend in and don’t distract the visitor, but upon closer inspection, it can be determined that this part is not original [5].

58

2.2. Neutral tone

After the removal of varnish and overpaint, the grey-brown colour of the original ground was visible, in several large areas of the painting because of damage or abrasion of the top paint layers. It was decided to cover all of the inserts – as well as the white fills along the joins – with the same colour as the ground layer, in order to have a neutral coloured surface before starting retouching. In order to cover all the inserts and fillings ranging in colour from white to black, an opaque paint was required. Other characteristics that were important were: the paint should be thin so it would leave the canvas structure visible, the layer should be even without colour differences, the paint should be removable in the future, and dry pigments should be used to tailor the colour. All of these characteristics could be (more or less) achieved with dry pigments in “2035 Lascaux Water Resoluble Medium” [6]. Unfortunately, nothing had been published about the acrylic polymer in this medium. Research by student Anna Don showed that even after extreme aging tests, the appearance of the medium was unchanged, and it was still easily removable; however, the medium was not “water resoluble”, as the label on the pot indicated [7]. Although in-depth studies were not available, it was deemed acceptable to use the acrylic medium, as it was only applied in areas of later additions and fillings, and on top of the isolating varnish layer.


VI. BRINGING THE REMBRANDT BACK TO LIFE

Figure 3. Saul and David, with the neutral tone applied on all the non-original parts of canvas. Photo made by Margareta Svensson.

Lascaux Water Resoluble Medium, was easy to work with. In the large insert in the upper right corner, the conservators used soft, broad synthetic brushes, of an inexpensive quality to produce a very even opaque layer that showed the underlying structure of the canvas and its paint layers. On top of the fillings – along the crenelated join and minute fillings in paint losses – tiny brushes were used. In this way, it was possible to construct a layer in one homogenous grey-brown colour, and with a surface texture similar to the rest of the painting.

2.3. The integration of the additions and abraded background

The very damaged original background had a distinct pattern of abrasion and required a significant amount of retouching. It was necessary to imitate the abraded surface of the original background when retouching the insert. This effect was achieved by making stamps using small pieces of canvas, coated with Windsor and Newton Acrylic gel (which

imitated the abraded texture of the paint). After drying, the stamp was dipped into a paint, which consisted of Lascaux Water Resoluble Medium mixed with a dark pigment mixture (consisting of black, burnt umber and red lake in varying proportions). The painted stamp was then applied by hand on top of the warm grey base tone: the small squares were stamped lightly onto the surface with minimal overlapping, and attempting to create a random pattern of dark brown marks. The stamping on the insert resulted in a pattern of abrasion similar to the original paint on the other side of the joins, both left and bottom. In the following stages, this enabled the conservators to build up the retouchings on the inserts in the same way as the abraded original background. For the retouching, the conservators used “Gamblin Conservation Colors” to fill in losses with small dots [8]. To match the colour of the background, the pigments Dragon’s Blood, Naples Yellow and a variety of blacks were indispensable. By taking little islands of original paint as a starting point for colour matching, the various nuances became apparent and even indicated folds in the curtain. The result was that the large insert and the join became completely integrated into the background when viewed from a distance.

3. DIFFERENTATING BETWEEN PAINTING TECHNIQUE AND LATER DAMAGES

The paintings that Rembrandt made in his later years are known for their experimental painting techniques. During the restoration, it was sometimes challenging to differentiate

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

59


VI. BRINGING THE REMBRANDT BACK TO LIFE

between his painting technique and later damage.

A closer look at the sleeve shows that solvent seems to be the cause of the loss of paint in that area. Here a very damaged black paint layer is visible. Rembrandt applied the black paint 3.1. The “damages” in the sleeve and robe of Saul directly on the ground, and also on top of white Overall, the two figures of Saul and David are and buff-coloured viscous smears and daubs of well preserved; however, one area was quite paint. The black layer was then locally covered disturbing: an area of abrasion down to the with brown brush strokes that were finished ground visible in Saul’s sleeve and the adjacent with additional white and yellow daubs of robe. Prior to the recent treatment, these areas which now only a few remain. In other words, had not been retouched, but the dark varnish between the damaged upper paint layers, had made the area less distracting. The fact that an underlying stage of painting can be seen, these areas are right next to each other at first where light brushstrokes indicate both the disguises the fact that the damage in the sleeve form and the highlights. These are evidence of and the damage in the robe have completely Rembrandt’s original painting technique; as we know from other late paintings by Rembrandt, different causes. he often applied daubs of paint to indicate the highlights, which he covered with semitransparent upper paint layers in subsequent painting phases. This technique of daubing is also nicely explained by Ernst van de Wetering when discussing Rembrandt’s Jewish Bride (painted in 1665, some 10 years after Saul and David). He describes this technique as “lying upon a seemingly chaotically brushed-on and smudged foundation are drippings of paint which, despite the apparently haphazard way they have landed in their positions, enhance the effect that these are costly fabrics interwoven with metal thread.” Van de Wetering explains further that these daubs are partly visible due to abrasion [9]. The black paint was retouched by the conservators to draw less attention to this damaged area. In contrast, in the robe the sharp edges of the Figure 4. a and b – Saul and David, Abrasion on Saul’s yellow and green paint seem to indicate that sleeve and shirt. Before and after retouching. Photo scraping was the cause of damage. It has been made by Margareta Svensson. suggested that Rembrandt himself might have done this. Where this top layer is missing, both 60


VI. BRINGING THE REMBRANDT BACK TO LIFE

dark and light smears of paint and thicker daubs of white paint from the undermodelling can be seen on top of the ground. The direction of these brushstrokes was not followed in the final painting. It is known that in other paintings Rembrandt scraped away paint with a palette knife to make changes or as an artistic means, for instance in his Self-portrait (Rembrandt, 1669, signed and dated, oil on canvas, 65.4 x 60.2 cm. Mauritshuis, The Hague [840]) or in The Apostle Paul (Rembrandt (and workshop?), c. 1657, oil on canvas, 131.5 x 104.4 cm, National Gallery of Art, Washington [1942.9.59]). The edges of paint in the damaged robe of Saul seem quite sharp, as if the paint was dry and thus hard and brittle when scraped. This suggests that the scraping is in fact damage that occurred later in the painting’s history, revealing the ground and some undermodelling and highlights. The conservators chose to complement the yellow and green brush strokes.

3.2. The pale highlights in Saul’s hand and under his eye

Before and during the recent treatment, many conservators and art historians had difficulty interpreting the pale highlights in Saul’s hand and under his eye. They appeared incongruous with the rest of Rembrandt’s painting. Research with the stereomicroscope indicated it was in fact original paint, but looking at these light touches of paint with UV radiation a slightly pinkish fluorescence showed that the mixed-in red lake had faded completely. A small crosssection of one of these brushstrokes confirmed the presence of a red lake.

Figure 5. a and b – Saul and David, Fading in highlight under Saul’s eye. Before and after retouching. Photo made by Margareta Svensson.

Long discussions with colleagues followed about what to do with this knowledge. Would it be unethical to try to bring back a tinge of red to let the highlights blend in and work as they were meant to? Applying only a few small dots seemed to make such a difference that the conservators proceeded by applying dots of a translucent glaze over these faded highlights in order to integrate them.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

61


VI. BRINGING THE REMBRANDT BACK TO LIFE

inspection, the unusual restoration history of the painting – with its crenelated join and many strips around the edges – is visible to someone looking for the evidence. At the same time, the slight unevenness actually is invisible to a beholder who simply wants to enjoy the painting.

Figure 6. Saul and David, after treatment. Photo made by Margareta Svensson.

4. CONCLUSIONS During the retouching of Saul and David, the decision was made to match the large, later insert in the upper right corner to the original parts of the painting. Retouching was not simply a matter of “filling in” losses in the paint. In this case the insert was so large and significant that several steps were required to adapt the surface texture to match the abraded areas in the background. To integrate the insert, a uniform colour similar to the ground layer, as well as a pattern similar to the abraded background, were necessary. For this large area of a uniform colour, Lascaux Water Resoluble Medium was a good solution, as it was easy to use and easy to apply. In other areas, the painting technique needed to be understood in order to fully comprehend the nature of the damage or paint loss. In paintings by Rembrandt, an area that at first appears to be abrasion or damage can in fact be due to the original technique. Upon close

62


VI. BRINGING THE REMBRANDT BACK TO LIFE

REFERENCES [1] The members of the advisory committee were: Martin BIJL (Private easel paintings conservator, The Netherlands), Blaise DUCOS (Curator of 17th- and 18thcentury Dutch and Flemish paintings, Musée du Louvre, Paris, France), Frits DUPARC (Former director of the Mauritshuis, The Hague, The Netherlands), Michiel FRANKEN (Curator technical documentation Rembrandt and Rembrandt school RKD (Netherlands Institute for History), The Hague, The Netherlands), Melanie GIFFORD (Research Conservator for Painting Technology in the Scientific Research Department of the National Gallery of Art, Washington, US), Emilie GORDENKER (Director Mauritshuis, The Hague, The Netherlands), Karin GROEN † (Research scientist, member of the Rembrandt Research Project), Volker MANUTH (Professor of Art History, Radboud University of Nijmegen, The Netherlands) and Ernst VAN DE WETERING (Former chairman of the Rembrandt Research Project). [2] The results of the technical research of Petria NOBLE can be found in the following articles: NOBLE, P.; VAN LOON, A.; JOHNSON, JR., C.R.; JOHNSON, D.H. - Technical investigation of Rembrandt and/or studio, Saul and David, c. 1660, from the collection of the Mauritshuis. In ICOMCC Lisbon, 2011, pp. 1-10 and NOBLE, Petria; VAN LOON, Annelies; ALFELD, Koen; DIK, Joris – Rembrandt and/or Studio, Saul and David, c. 1655: visualizing the curtain using cross-section analysis and X-ray fluorescence imaging. In Technè, no 35, 2012, pp. 36-45. [3] DE VRIES, A.B., TÓTH-UBBENS, M, FROENTJES, W. Rembrandt in the Mauritshuis, Alphen aan de Rijn: Sijthoff & Noordhoff International Publishers BV, 1978. [4] The painting of the insert was identified from the x-ray by Gregor WEBER, Head of the department Fine and Decorative Arts at the Rijksmuseum Amsterdam. [5] Marya ALBRECHT applied these retouchings. [6] For more information about Lascaux Water Resoluble Medium see http://lascaux.ch/pdf/en/produkte/ malhilfen/malmittel/52311.02_emulsion_.pdf [7] DON, Anna, - An Investigation into the Effect of Light and Thermal Artificial Ageing on the Water Solubility of Lascaux Water Resoluble Medium 2035 - Thesis for the Conservation BA(Hons) at City & Guilds of London Art School, 2014-2015 [unpublished]. Forthcoming publication: Spring issue of 2016 of the Picture Restorer. [8] For more information about Gamblin Conservation Colors see http://www.conservationcolors.com/colors.html [9] VAN DE WETERING, Ernst – Rembrandt. The Painter At Work – Amsterdam: Amsterdam University Press, 2009, p. 158.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

63


64


VII

Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century


VII.

Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century

Catarina Pereira (1) (1) School of Arts, CITAR Portuguese Catholic University (Porto); R. de Diogo Botelho 1327, 4169-005 Porto, Portugal; catarinacortes@gmail.com

Abstract Retouching glass plate negatives was a practice that emerged about the same time as the glass plate negative itself. How was photography being retouched in the early 20th century? Today there are generally available known digital tools. A hundred years ago, the retouching was done by hand, by the photographer, or by specific professionals that don’t distance themselves, in technical demand, of the arts of drawing and painting. But the retouching was invisible in the final object, because the changes were done on the negative. Its contemporary books, in the form of manuals, are a window to the past telling us about the techniques and materials used. Existing archive collections of photographic glass plate negatives are testimony to the expertise of photographers and the practical use of those books. The present work will show examples of tools and materials used for retouching of photographic glass plate negatives, taking as an example a portrait collection at the Photographic Archive of Lisbon. Also some considerations are done about the conservation of retouched glass plate negatives in archive collections.

Keywords Photography; Glass plate negative; Historical retouching; 20th century.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

67


VII. Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century

1. Introduction In the early 20th century, photography is already established in society and within the reach of many. Photography studios exist in cities and travelling photographers take photography to the rest of the population. Like today, at that time, photography was divided into key sectors, among them, photojournalism, portrait, artistic photography.Like today, not short from controversial, in particular in the sector of portraits, photography was commonly manipulated, better said retouched, for several reasons: correction of photographic flaws, to improve or modify the composition, contrasts etc., or as an artistic expression. And the retoucher wasn’t far off from the painter or colourist, in fact, the old miniaturists, out of work with the dawn of photography, became retouchers [1]. Photography books from the final of the 19th century, beginning of the 20th century, would include chapters on retouching and several authors dedicate entire books to the subject [26]. They were written as practical manuals and would teach about materials, tools, recipes, techniques and effects. A complete manual would often include more or less detailed considerations and diagrams about human anatomy. But, the appreciation of the photographic specimen, positive and negative, as a cultural object, is a recent line of thought in conservation and restoration. Until very recently, to save a picture simply meant to replace it, by means of a new copy. The material object itself was not valued, most of the photographic specimens had no intrinsic value. Currently, these 68

negatives are historical documents whose value exceeds the photographed subject, the object itself also has historical, technical and artistic value that must be preserved. Like every other branch in conservation and restoration, the knowledge should start in understanding the materials and the techniques used. Photographic negatives in archives collections, easily reach the number of hundreds, and restoration treatment is viewed similarly to that of other archive documents. The standard treatment in Portuguese archives is to digitalize the negative and preserve it as it is. Here, some considerations are made about the historical technique of retouching, and issues in conservation of retouched glass plate negatives.

2. THE NEGATIVE COLLECTION AT THE PHOTOGRAPHIC ARCHIVE OF LISBON

The photographic archive of Lisbon is the depository of photographic heritage of the city of Lisbon, since 1950 to the date. The archive is responsible for the preservation of the collections and making them accessible for researchers and the general public, allowing consultation on site, and on digital records, available on-line; and by organizing exhibitions and other public events [7, 8]. But there is one collection, housed at the archive, which is not directly related to the city of Lisbon, the NEG collection (short for negative). This collection is composed of different objects, but mainly gelatin silver bromide glass plate negatives, from different


VII. Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century

formats and dates, going back to the beginning of the 20th century [7]. This collection has 5136 objects 3% of which are retouched and/or have masks. These negatives are retouched with the use of different techniques that were the focus of a previous work [9]. The study of this collection allowed the confrontation of the used techniques and, at some level, the types of materials used for retouching, and the information reviewed in historical technical sources [9]. It was possible to identify in the collection each technique mentioned in manuals and other books [2-6] with reference to retouching.

Figure 1. Detail showing the use of graphite pencil and grattage/etching to obtain a more symmetrical moustache. (from the negative: AFCML NEG000335)

Grain – Optical interference to create a smoother aspect, on the left image, face wrinkles were attenuated with random patterns done with graphite.

3. HISTORICAL SOURCES ON HOW TO RETOUCH

Reading a selection of these works [2-6] was meant as the initial step for the study of negative retouching. The objective was the identification of the possibly used materials and the techniques. This is a crucial step for a better understanding of collections with negative retouching and its conservation state and hence its proper future conservation. Next is the general description of the main retouching techniques.

Mattolein – Resin varnish (for example gum arabic or mixtures of different materials); The varnish prepares the gelatin surface for retouching.

Repairs – of gelatin speckles and other defects, with graphite or colorants such as neu-coccin.

Grattage – or etching is the scraping of the gelatinous surface with knife, needle or abrasive powder: Figure 1 shows that a mixed technique was used: graphite pencil erased the disheveled hairs; and gratagge/etching was used to draw hairs to obtain a more symmetrical moustache. When the subject areas are too bright or to dark, the highlights and contrasts were also adjusted by means of graphite and etching simultaneously.

Makeup – liquid colorant or powder is used to adjust brightness and contrast: for example to attenuate over-shadowed areas, or to give more contrast for example when the subject tone is close to the background.

Masks – Usually done in order to isolate specific features or for compositional purposes. The masks were done with different materials

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

69


VII. Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century

provided that they were opaque. Common used 4. SOME CONSERVATION ISSUES materials were: paper, paint, bitumen, among others. The materials used for retouching negatives are part of the object and should not be removed in any conservation treatment. Also, the retouching is the testimony of the photographer’s intention, even though it would be invisible on the final object, the positive prints.

Figure 2. Image with transmitted light (a) and positive image obtained with digital tools (b). Showing isolation of one of the persons depicted, reconstruction of the right arm and new background (from the negative: AFCML NEG004383).

Figure 2 shows an example of the use of all of the described techniques. The objective was to isolate the woman from an original portrait of three subjects. The man stand in behind is erased by making a new background with red colorant applied with the tip of the fingers, as evidenced by the finger prints visible in the red areas of the gelatin surface (figure 2a). The child on the woman’s lap was first erased by etching; and then the shoulder and arm were drawn with graphite. The final portrait would be obtained with a mask isolating only the woman’s torso as exemplified on the figure2b.

70

Figure 3. Detail of the same negative of figure 1, showing the final result. Positive image obtained with digital tools. (from the negative: AFCML NEG000335)

Nowadays it has become common procedure to archives digitally convert the negative collections and make them available, in the positive form (figure 3), to the general public. This practice has been put into question, as this positive image is not the true record of the existing object. When the negative presents retouching, this question is particularly


VII. Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century

important as the retouching was done in a way that was meant to be invisible in the positive object. Furthermore, the retouching material might have deteriorated with time, and no longer fulfills its purpose; which means, the digitally converted positive won’t show the intended image. In situations, as the one shown on figure 4, where there is some deterioration of the materials used to retouching, the question is even more relevant. Does, in fact, the positive image, show a true or most relevant record? In a conservation intervention should the conservator retouch the negative and try to reproduce the photographer’s intentions?

5. FINAL REMARKS The retouching of negatives, and photography, in general are relatively recent areas of study in conservation and restoration. Old books and manuals are important sources of information on techniques and materials used for retouching. Future studies on available historical information, materials and techniques used and the conservation state of collections, are still needed for better understanding of conservation issues and the development of more specific conservation procedures.

ACKNOWLEDGMENTS To the Photographic Archive of the City of Lisbon (AFCML), Inês Viegas (AFCML director); Luís Pavão; Ana Luísa Alvim and Claudia Damas.

Figure 4. Detail showing deterioration of the historical retouching and corresponding positive image obtained with digital tools (from the negative: AFCML NEG000648).

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

71


VII. Materials and techniques for retouching glass plate photographic negatives in the beginning of the 20th century

REFERences [1] HANNAVY, John. (Ed.) - Encyclopedia of Nineteenth-Century Photography. New York: Routledge, 2007. [2] ZAMBONI, Carl. - Anleitung zur Positiv und NegativRetouche: Herausgegeben und durch praktische Beispiele erläutert. Halle a. S.: Wilhelm Knapp, 1888. [3] HUBERT, J. - The art of retouching: with chapters on portraiture and flash-light photography. 7ª Ed. London: Hazell, Watson, & Viney, Limited, 1895. [4] KLARY, C. - L’art de retoucher les négatifs photographiques. 4ª Ed. Paris: Gauthier-Villars et Fils, Imprimeurs-Libraires, 1897. [5] GÉRARD, L. - Comment on retouche un cliché photographique. Paris: Ètienne Chiron Èditeur, 1925. [6] MARIN, C. - Il Ritocco - Positivo e negativo: quimico, manual, meccanico. Trieste: Edizioni Tecniche Fotografiche, 1956. [7] VILAS BOAS, A. - Aquisição e organização de colecções de fotografia, uma experiência no Arquivo Fotográfico da Câmara Municipal de Lisboa. Encontros - Conservação de Fotografia. Lisboa: Arquivo Fotográfico Municipal, 1997. [8] DIAS, Luísa Costa. - A experiência da abertura à consulta do público de Arquivo Fotográfico Municipal, após remodelação. Encontros - Conservação de fotografia. Lisboa: Arquivo Fotográfico Municipal, 1997. [9] PEREIRA, C. - O retoque do negativo fotográfico: estudo de uma colecção do Arquivo Fotográfico da Câmara Municipal de Lisboa. ECR , Vol. 2, (2010), pp.38-57. [10] NORRIS, D. H.; Gutierrez, J.J. (ed.) - Issues in the Conservation of Photographs. LA: Getty Publications, 2010. [11] PAVÃO, L. - Conservação de colecções de fotografía. Lisboa: Dinalivro, 1997.

72


VIII

Hand building a low profile textured fill for a paint/ground loss


VIII.

Hand building a low profile textured fill for a paint/ground loss

Francisco Brites (1), Leslie Carlyle (1), Raquel Marques (1) (1) Departamento Conservação e Restauro, Faculdade de Ciências e Tecnologia, Universidade Nova

de Lisboa; 2829-516 Caparica, Portugal; E-mail address: f.brites@campus.fct.unl.pt; leslie.carlyle@btinternet.com; raquel.marques.rm@gmail.com

Abstract In order to prepare for reintegration, the topography of an infill from paint/ground lacunae needs to

match the texture of the surrounding paint. This paper describes the execution of a shallow textured infill on an early 20th century portrait in oil executed on a “mesh”’ (open weave) canvas with a particularly thick size layer. The fill and subsequent reintegration is for an area of loss (approx. 4.0cm x 2.3cm) associated with a tear (which was mended thread to thread with Paraloid® B-72). On this painting, both the ground and paint layers are very thin (~200µm) when compared with a range of cross-sections from other paintings (~300µm), and the overall surface texture is not pronounced. Initial attempts to cast a silicone mould of the surface texture were frustrated because the painting remains on its original stretcher, and achieving conformation of a barrier film against silicone staining by using the low-pressure suction table was not possible. Because of the complex surface requiring infilling (replacement of the thick size layer, followed by a textured fill), two different fill materials were used, Beva®371b with kaolin, and a top layer of Mowiol® 4-88. The final infill was plasticized with an infusion of Beva® 371b in white spirits (60:40). The approach to constructing the infill and the technique of hand building the texture to match the very low profile of the original paint texture is described. A better understanding of the characteristics and behaviour of the materials present in the painting was important in the choice of the selected materials.

Keywords Oil painting; Textured fill; Mowiol®4-88; Beva®371b and kaolin.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

75


VIII. Hand building a low profile textured fill for a paint/ground loss

1. Introduction This official portrait in oil of Januário Correia de Almeida, from 1901 had a significant paint loss associated with a tear on the upper right side, apparently caused by a blow to the back of the canvas. The image was also not acceptable for display due to a thick layer of dust and dirt (Fig.1(A)).

the tear area, see Fig.1 (b) and (c)). Normally a painting with such a thick size layer should have on-going problems with paint flaking and overall dimensional stability, related to RH response, since animal glue undergoes severe dimensional changes which the paint composite cannot follow and which affects the planar stability of the painting [1]. However in this case the painting’s overall tension was remarkably even, with almost no planar distortion and very minimal flaking. Isolated samples of the size layer indicated very little response to water. A better understanding of the size layer was important in the design and application of the treatment, in particular of the tear and missing paint1. Therefore the painting’s size layer was

Figure 5. (a) Overall before treatment of Januário Correia de Almeida, belonging to Colecção Caixa Geral de Depósitos, Lisbon Portugal; (b) Macro image of the tear area showing the size layer in the fabric; (c) Support with the Baxter Thread Counting Method: the thin threads and low thread count of the painting’s canvas are evident in this image photographed with a 1cm border of graph paper; a method introduced by Anne Baxter (Private Restorer, Montpellier, France), that avoids the need for in-situ thread-counters.

The aim of this project was to create a textured fill for the loss which would match the paint’s shallow texture and retain some flexibility. The aim was also that the fill would not introduce significant changes in the behaviour of the canvas surrounding the loss. The painting presents an unusually thick size layer on an open weave canvas (best seen over 76

studied in terms of its RH and water response (less than 4% change, compared with a layer of freshly prepared and dried size using rabbit skin glue which exhibited dimensional increases of up to 24% in high RH). To investigate size layer treatments, including those designed to render the size unresponsive to moisture and water, reconstructions from calves’ feet gelatine, using recipes from the latter part of the 19th century were made and compared with the painting’s size which was apparently prepared with a treated food-grade gelatine. This work is reported elsewhere [2]. 1

The size layer was analysed by Micro Fourier Transform Infrared Spectroscopy (µ-FTIR) and confirmed the presence of a protein based material with the characteristic bands of the Amide A, I, II and III. The Amide A was observed at 3300cm1 (N-H stretching), Amide I was present at 1653cm-1 (C=O stretching), Amide II at 1547cm-1 (C-N-H bending) and Amide III was seen at 1339cm-1 (C-H bending) [3]. Infrared spectra were obtained using a Nicolet Nexus spectrophotometer coupled to a Continumm microscope (15x objective) with a MCT-A detector cooled by liquid nitrogen. Spectra were collected in transmission mode, between 4000 -650cm-1 and 128 scans, using a Thermo diamond anvil compression cell.


VIII. Hand building a low profile textured fill for a paint/ground loss

2. Treatment Prior to the infilling 2.1. Surface Cleaning and Consolidation

The painting presented a very thick layer of dust and dirt, which was hindering the overall reading of the painting since most of the colours were very dull. The surface was dusted with a soft natural hair Japanese brush, then surface cleaning was performed in two stages. Given the low moisture response of the size it was possible to use aqueous materials, details are presented in [2].

the affected area (Fig.2). The plasticine was adjusted to conform to the thread distortions. Once aligned the threads were joined by dropping a 40% solution of Paraloid® B-723 in xylene to the spot where the thread ends slightly overlapped. B-72 exhibited good tensile strength and flexibility, enough to maintain the threads in place at this stage of the treatment. Since the painting, on its original stretcher, showed little evidence of RH response overall, it appeared that the repaired threads would not be under significant further tension4.

Consolidation of the paint/ground layers associated with areas of loss was carried out with warmed BEVA®371b2 (1:1 solution in white spirits), followed by light pressure and heat applied through silicone coated Melinex® with a heated spatula.

2.2. Tear repair

To ensure good alignment and easy manoeuvrability of the fibres, a piece of blotting paper (4cm long by 1,5cm wide), previously moistened with distilled water, was suspended over an area covering approximately 14 threads at once (similar to that used in the overall flattening, Fig.3). The moisture relaxed the fibres allowing them to be realigned. To achieve realignment of the distorted threads a small raised lump of plasticine covered with thin Melinex® (25 microns) was placed on a

Figure 6. Illustrations

showing how threads were realigned across from each other using plasticine covered with Melinex® (A) and joined with Paraloid® B-72 (B).

2.3. Local Flattening

After realignment, the threads overall were still out of plane, therefore the area was flattened with local moisture treatments followed by weights. A bridge of moistened blotting paper, not touching the paint surface, but suspended over

support board underneath the painting, below 2

BEVA® 371b adhesive replaces the original cyclohexanone resin Laropal K80 in BEVA® 371 with the urea aldehyde resin Laropal A81. The other ingredients, reported to be common in both formulations, aretwo EVA copolymers (Elvax 150 (45%), A-C 400 Copolymer (15%)); a phthalate ester plasticizer, Cellolyn 21 (4%); and a paraffin wax (9%) [4].

3

Paraloid® B-72 is a copolymer of ethyl methacrylate and methyl acrylate (EMA/MA, 70/30 proportion) [5].

4

Contributing to the dimensional stability of this painting were the thin canvas threads with wide interstices locked in place with the moisture resistant treated gelatine. Thanks to Jilleen Nadolny for pointing to the low ratio of cellulose in the support.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

77


VIII. Hand building a low profile textured fill for a paint/ground loss

the exposed fabric, was positioned to create a high RH micro climate (Fig.3). This action was carried out in series of individual sections progressing across the tear to minimise fabric distortion and achieve complete flattening.

Figure 7. Illustration of the bridge of moistened blotter held at each edge by small glass weights (blue boxes), creating a microclimate of raised RH without touching the paint.

2.4. Creating the textured infill

After the tear repair and flattening, in areas of the fabric where the size layer was missing in the canvas interstices, fabric distortions returned. Furthermore the missing size layer between threads meant that infill material could pass through to the back of the painting. Therefore the first step was to insert a size layer replacement in the interstices.

filler, in this case, kaolin6. The mixture is then pressed between sheets of silicone coated Melinex® using an iron to form a film. A film approximately the same thickness as the size layer was achieved, then cut into small squares which were then inserted into the areas where the original size layer was missing. A small metal dental tool was heated and pressed over silicone coated Melinex® on top of the filler, softening it to the point that it bridged the gap between the threads by sticking only to the outside edges of the threads (Fig.4). Threads were not saturated as the BEVA®371b fill was not melted, therefore their behaviour is likely to be similar to the surrounding original size-fabric.

Figure 8. Illustration of infill inserts (BEVA+Kaolin) replacing the previously lost size layer.

2.4.1. SRAL Method using BEVA®371b and kaolin

Developed at the Stichting Restauratie Atelier Limburg (SRAL5), BEVA®371b with the addition of kaolin forms a flexible infill material ideal for the size replacement. The SRAL method involves evaporating the solvents from BEVA®371b in a fume hood overnight. It is then heated and mixed with a

5

78

In 2013, Kate Seymour, Head of Education at SRAL, provided a workshop at DCR-UNL to instruct on the use of this method. It was originally developed by SRAL’s senior painting conservator, Jos van Och.

2.4.2. The final infill: selection and criteria

The area of paint/ground loss was very shallow and the surrounding paint surface was textured by the underlying canvas and low profile brushwork. The technique of casting the surface texture using silicone molding material was not possible since a barrier film was required to 6

10gr BEVA® 371b + 7.5gr Kaolin. The proportion depends on the properties desired for the filling material.


VIII. Hand building a low profile textured fill for a paint/ground loss

prevent silicone staining in the paint/ground. Previous experience [6] indicated that a significant vacuum was needed to achieve full conformity of the film to the paint surface. Since the painting remained in its original stretcher it would be difficult to pull a vacuum without endangering the rest of the painting. Therefore the alternative, of hand-building a textured infill, was considered a better option. For hand-building the infill, a range of materials was considered (see Table 1). Those, which were flexible, presented disadvantages in working (BEVA®371b and kaolin, and Beva® Gesso-P) whereas those which worked well, could form brittle films in the very thin layer required (e.g. rabbit skin glue plus chalk). Mowiol® 4-88, a polyvinyl alcohol, was chosen, prepared in a 20% solution with distilled water (10g Mowiol to 50ml water). To that was added Kremer Champagne chalk (a natural chalk) to form the desired consistency.

Material

Advantages

Disadvantages

Beva®371b + Kaolin

-Softens over a broad range of temperatures; -Flexible

-Could not achieve textured surface because no silicone mould was possible

-Ready for use; -Flexible; Beva® Gesso-P -Low response to RH.

-Translucent until it dries; -Requires use of toxic solvents

Mowiol® 4-88 (PVAL) + Kremer Champagne Chalk

-Water soluble; -Easy to prepare and work with; -Can be worked in a very fluid state;Easy to remove

-Reported to be brittle; -Reported dimensional response to RH fluctuations [5].

Rabbit Skin Glue + Kremer Champagne Chalk

-Easy handling properties; -Good adhesion and appropriate cohesion.

-Susceptible to changes in extreme Temperature and RH; -Needs to be applied warm.

2.5. Application and texturing of Mowiol® 4-88

According to Horie, polyvinyl alcohol (PVAL) is very stable to oxygen and light ageing since chain scissions occur very slowly, but he notes that it might become insoluble in acid or alkaline conditions [5]. Future insolubility of this binder was not considered a significant issue as it will not cover original paint and can be removed mechanically. Mowiol® 4-88 is very easy to apply at room temperature in fluid brushstrokes and has a long working time which allows alterations during application. After drying it remains water soluble for easy adjustments. The infill was initially applied in a thin film and allowed to dry. This step was repeated until the desired thickness was achieved.Applying water-based infill materials in a series of thin layers which are dried in-between coatings ensures that the material does not crack during application. When the infill had reached the required thickness, it was smoothed with a cork covered with fine net fabric in order to obtain a uniform surface. To achieve a textured surface matching the surrounding paint, the fill was applied quite fluid on top of the previously dried and smoothed infill. A series of dots and lines to mimic the canvas texture were first created then reference points from the surrounding paint, such as fine lines from brushstrokes were extended into the fill area (Fig. 5).

Table 1. Infill options.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

79


VIII. Hand building a low profile textured fill for a paint/ground loss

hand, the lack of complete penetration was positive, since it was important not to saturate the canvas threads with Beva®371b in the tear area thereby changing their behaviour. However it was also thought to be a problem for introducing flexibility to the fill.

Figure 9. Different images of Mowiol® 4-88 + chalk application and texturing. (a) Shows reproduction of the canvas texture, by doing vertical and then horizontal lines; (b) Shows how the texturing was carried out from the outside into the center; (c) final appearance after smoothing down the texture by light application of a moistened cotton swab; (d) final appearance after proper inpainting.

3. beva®371b isolating layer Since Mowiol® 4-88 can be subject to mechanical cracking, an isolating layer that would also increase its flexibility as well as reduce its tendency to absorb water vapours was sought. Empirical testing was carried out to systematically evaluate the effect of brushing Beva®371b onto a film of Mowiol® 4-88 + chalk to demonstrate if it enhanced flexibility. Samples of the filler were applied in controlled thickness onto thick Melinex® (100 microns) and dried. They were coated with Beva®371b in two dilutions, 1:1 in white spirits and 60:40 and in one, two or three applications. Samples with and without the Beva®371b were tested for flexibility by bending over a curved surface. Inspections of the edge of the filler and the back, as seen through the Melinex® indicated that the Beva®371b did not penetrate throughout the full thickness of the samples. On the one 80

Tests with Beva®371b applied to thin films of the fill showed that on extreme bending (done over the surface of a narrow 10ml graduated cylinder) the fill material easily cracked. However, in bend tests over the outside surface of a large beaker (200ml) the 60:40 dilution did inhibit cracking compared with the same thickness of fill material not treated with Beva®371b and bent over the same beaker. A further advantage of applying Beva®371b is that it is likely to reduce the Mowiol® 4-88 response to humidity (Horie reports that it is hygroscopic, absorbing water vapours above 75% RH [5]). However RH response must also consider that the infill will be sandwiched between layers of inpainting using a synthetic resin binder (Laropal A81) and the relatively non-hygroscopic layer of size below.

4. CONCLusions This work revealed the importance of understanding the characteristics and behaviour of the materials present (the low RH/water response of the size layer in the painting), and of anticipating each step in the treatment (the alignment of canvas threads prior to flattening). The greatest challenge was to choose appropriate infill materials, and to create a replacement size for infilling the canvas


VIII. Hand building a low profile textured fill for a paint/ground loss

interstices prior to applying the top infill. Finally the need to recreate a convincing surface texture in the paint loss involved choosing a fill material that would perform as needed. The bending tests carried out to test the effect of an isolating layer of Beva®371b were extreme, since the fill will not have to undergo this level of displacement. In fact gentle manipulation with our fingers gave the most valuable information, since we could experience an increase in flexibility with the Beva®371b coated infill samples. The level of description in this paper helps to explain the methodology adopted to solve the practical issues. Although the solutions found for this particular case were successful they may not be applicable to other objects. Conservators need a range of options in order to fulfil their requirements in a wide variety of situations.

REFERences [1] MECKLENBURG, Marion F. – Micro Climates and Moisture Induced Damage to Paintings, Museum Microclimates, National Museum of Denmark, 2007, pp.19-25 ISBN 979-877602-080-4. [2] BRITES, Francisco – Analysis and Treatment of a male portrait in oil and a study of the size layer with reconstructions from Vibert’s recipe (1892), Master Thesis, Universidade Nova de Lisboa, Faculty of Sciences and Technology, 2015. [3] STUART, Barbara – Biological Applications of Infrared Spectroscopy. John Wiley & Sons, 2007, pp.113-116. [4] PLOEGER, Rebecca; MCGLINCHEY, Chris W.; RENÉ DE LA RIE, E – Original and reformulated BEVA®371: Composition and assessment as a consolidant for painted surfaces. Studies in Conservation, Vol. 60, no. 4 (2014), pp. 217-226. [5] HORIE, Charles Velson – Materials for Conservation. Organic Consolidants, adhesives and coatings. Oxford: Butterworth-Heinemann, 1987, pp.96-99. [6] MARQUES, Raquel – Analysis and Treatment of a Nineteenth Century Oil Painting, Master Thesis, Universidade Nova de Lisboa, Faculty of Sciences and Technology, 2014.

materials and suppliers equipment

Acknowledgements We are very grateful to the owners of the portrait, Colecção Caixa Geral de Depósitos, Lisboa, Portugal and Isabel Corte Real for allowing us to investigate and treat this painting, and to Professor Maria João Melo for her help and advice regarding the µ-FTIR analysis of the size layer.

Heat Spatula:

Willards of Chichester, Sussex, England. Controller type ‘E’. Serial No. 0471-479.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

81


VIII. Hand building a low profile textured fill for a paint/ground loss

materials Product

Supplier

BEVA®371b (40% solution)

Kremer Pigmente GmbH & Co. KG www.kremer-pigment.de

Distilled water, Type I Water Station, Diwer Technologies

Faculdade de Ciências e Tecnologia, UNL, 2829-516, Caparica, Portugal

1. Melinex® sheet (25 microns), polyester film; 2. Melinex® sheet (100 microns), polyester sheet

PEL: https://www.preservationequipment.com/Home

White Spirits Xylene

Valente & Ribeiro Lda, Bairro Xetaria Campina Pequena, 2605-012 BELAS (Sintra- Queluz e Belas) http://valenteribeiro.com/pt

Paraloid® B-72 Mowiol® 4-88

Kremer Pigmente GmbH & Co. KG

Kaolin, Kremer 58250

www.kremer-pigment.de

Chalk from Champagne, Natural Calcium Carbonate Plasticine

82

Artist’s Material Supply Store, Lisbon Portugal


IX

HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS


IX.

HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS Frederico Henriques (1,2); António Candeias (2); Alexandre Gonçalves (3); Eduarda Vieira (1) (1) Universidade Católica Portuguesa (UCP); Escola das Artes; Centro de Investigação em Ciência e Tecnologia das Artes (CITAR); Rua Diogo de Botelho, 1327, 4169-005 Porto; E-mail address: frederico.painting.conservator@gmail.com; evieira@porto.ucp.pt (2) Universidade de Évora/ Laboratório HERCULES; Universidade de Évora Palácio do Vimioso; Largo Marquês de Marialva, 8, 7000-809 Évora; E-mail address: candeias@uevora.pt (3) CERIS, ICIST, Instituto Superior Técnico, Universidade de Lisboa; Av. Rovisco Pais, 1049-001 Lisboa; E-mail address: alexandre.goncalves@tecnico.ulisboa.pt

Abstract In this paper we present some results of the use of digital documentation techniques for the characterization and analysis of Cultural Heritage. The used tools (geographic information systems, digital photogrammetry and computer graphics software) allow us to explore new forms of recovery of digital documentation. The typology of objects where these technologies may be applied is diverse, from public artworks to objects integrated into a museological context. For the performed exercises, which were presented in RECH 3, were given as examples objects from the urban parks in the city of Porto, from the National Museum of Soares dos Reis, from the Major Seminary of Our Lady of the Conception of Porto, from the Church of the Holy Spirit in Évora, and from private collectors, among others. The results show that through current digital techniques it is possible to document and characterize in a hyper-realistic manner the surfaces of the works, analyze the degradation phenomena with high accuracy, annotate technological evidences, develop virtual scenarios with infographic profile, reconstruct missing elements of objects, and even make chromatic reintegration on 3D objects. In practice, the actual virtualization works with digital photogrammetry and with recent techniques of computer processing that provide a handy tool for the documentation of heritage works. This kind of virtualization is a strong alternative to documentation made with laser scanning, often costly. Nonetheless, photogrammetry data capture always requires a high technical accuracy in the photographical acquisition and long post-processing elaboration to develop the 3D models.

Keywords Heritage Documentation; Geographic Information Systems; Photogrammetry; Computer Graphics; 3D retouching. III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

85


IX. HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS

1. Introduction Documentation of Cultural Property is not a recent subject: the interest and the need to make documentary records, with the most diverse techniques, has always been present in the heritage studies context. However, what has distinguished the models applied to documentation is always the reflection of practices of coeval technologies. Today, after the unequivocal implementation of computerbased technologies, the development of digital records is a reality. This article references the use of three types of digital tools for the characterization of heritage interest objects: (i) geographic information systems (GIS), (ii) photogrammetry, used for creating 3D models, and (iii) computer graphics software. The goal of this paper is to present and discuss the role of these low-cost technologies (some might be even cost-free) in heritage documentation and post-processing work with virtual chromatic reintegration.

1.1. Geographic Information Systems (GIS)

In 1999 in Rome, under the auspices of UNESCO, an important event dedicated specifically to the use of geographic information systems (GIS) in Cultural Heritage, the Gradoc, was held [1]. Since then, multiple studies have been developed: during the 2000s several projects in the international context with GIS in Cultural Heritage were promoted [2]. There is a number of open-source software for desktop computers that have contributed to the spread of mapping technologies (e.g. GRASS; QGIS®; gvSIG,

86

KOSMOS, among others) as well as a strong implementation of trade license programs, such as ESRI’s ArcGIS®. Also, several web-based applications have been playing an important role in mapping (e.g., Google Earth, Mapbox): although such web-based applications are not directed to advanced spatial analysis, many have capabilities that allow their use in the documentation of cultural items, enabling to easily identify and locate places and objects in the territory (Google Earth, Google Maps, Open Street Map; Mapbox, among others).

1.2. Photogrammetry Software

Photogrammetry is a well-known technique [3] [4] [5] [6], especially in built heritage context [7]. Recently, there has been a huge increase in this technologyin particular withhyperrealistic 3D models processed by the cloud server. Given the recent evolution of algorithms, the creation of 3D models is very fast, because the actual process does not need camera calibration or marking homologous points between photographic pairs. At present, and after some specific technical care in the photographic acquisition, the process is fully automatic. The most common designation for 3D models production with photographic resources is often called a “Structure From Motion” (SFM) or “image-based surface reconstruction” [8]. In this project for making 3D models, the Python Photogrammetry Toolbox (PPT) [9] and a beta version software, Memento from Autodesk®, newly named Remake were used [10].


IX. HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS

1.3. Digital Representation and Computer Graphics Software

Computer graphics is another area that has driven significantly heritage dissemination and exploitation, either from the use of 2D imaging programs (Photoshop®, GIMP, Inkscape, among others) or the full development and applications of 3D technologies. Within the production of three-dimensional models, this is a significant development area in virtualization for the animation, cinema and digital games industries. The same software is also used for the recreation of ancient scenarios and sites, in the archaeological context. Some commercial software are well known, such as 3D Max Autodesk®, while Blender (with a GNU General Public License) has the potential to revolutionize the contemporary digital documentation in cultural heritage, as it is one of the programs with greater utility and versatility in computer graphics, from the simple chromatic reintegration of objects, to the development of virtual scenes [11]. Computer graphics have the ability to contribute for the development of scientific based museological contents and museographic utilities [12] [13], such as the recreation of virtual museums, the production of representations with didactic interest to illustrate objects (Figure 1) and design animation for educational tools.

Figure 1. 3D model of representation of the marble sculpture “Desterrado”, from the National Museum of Soares dos Reis, in Porto.

2. Methodologies In the specific context of the presentation made in RECH 3, several examples ranging from geographic information systems (Figure 2) to various photogrammetric 3D models (Figure 3) and some virtual reconstructions (Figure 4) were discussed. In it, the goal was to describe applications within the chromatic reintegration of virtual objects. Thus, initially the chromatic reintegration of the resulting images (2D views) is presented, while a later phase dedicates to the 3D reintegration.

Figure 2. Aerial view of the distribution of public art in the Crystal Palace Gardens in Porto. III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

87


IX. HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS

pencil tool brush) and the stamp (clone stamp tool). To determine the color, the eyedropper tool can be chosen. Besides the tools indicated, many other editing functionalities can be used, such as the magnetic lasso and the magic hand tools, which highlight selection areas (Figure 5).

Figure 3. Representation of a scene with a photogrammetric object (Angel Messenger, Irene Vilar).

Figure 5. Some examples of image-editing tools in Photoshop®.

Figure 4. Creative composition with 3D objects belonging to the gardens of the Crystal Palace, Porto.

2.1. Chromatic reintegration of images

The chromatic reintegration of 2D images is made using digital editing and image processing. In it, Photoshop® is the most commonly used commercial product [14]. Regarding free programs, GIMP is the most widespread tool. For digital image processing the software named ImajeJ [15] is also one interesting option to explore in heritage documentation. It iswritten in Java, which allows it to run on Linux, Mac OS X and Windows, in both 32-bit and 64-bit modes. ImageJ and its Java source code are freely available and in the public domain. In the reintegration using Photoshop®, two main tools are possible to use: the brush (tool and

88

2.2. Reintegration of 3D objects

Blender software was used in the postprocessing of 3D objects [16]. After importing the photogrammetric model (import obj.) and respective texture (material> color> texture image), chromatic reintegration is done by picking the interaction panel dedicated to “texture paint”. If the object has a texture, it can be reintegrated directly in the model. Then it is possible to select the type of brush, and in color space choose a color (Figure 6).


IX. HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS

Software

Class

Work time

Sculpture photo acquisition

None

Photography

2h

Mapping a Public Art Collection

Mapbox

WebGIS

3h

PPT or Memento

Photogrammetry

4h

(Cycles)

Computer Graphics

5h

Blender (Cycles)

Computer Graphics

7h-12h

Operation

Produce a 3D model of one sculpture

Figure 6. Snapshot of a Blender session for chromatic reintegration with brush, in mode system “texture paint”.

It is important to note that if the object has no texture, it should be created, in order to make the chromatic reintegration of the object. As in 2D editing with Photoshop®, the main tool is the brush clone. With this tool it is possible to reproduce all varieties of colors present in the object. It is possible also to control the brush size, determine the radius in pixels and an application strength. For understanding the methodology is presented a table which compare type of work, software class and work time (table 1).

(Autodesk)

Create a virtual scene Render a virtual scene with animation

Blender

Table 1. Relation software’s.

between

main

operations

and

3. RESULTS AND DISCUSSION The techniques presented in the paper are used for colour retouching. Some of the problems related to colour reproduction is the colour accuracy of the photographic image acquisition. For that reason is important to have in mind the correct adjustment of photographic parameters, such as the white balance, field of view, exposition time, among others [17]. The colour reproduction of 3D models depends of knowledge and skill of operator, in particular in scenes that contain more than one object, where we have multiple sources of lighting and the objects are non-uniformly illuminated [18] [19] [20]. In this project, results with the intersection of documentation technologies (GIS, photogrammetry and 3D modeling) were

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

89


IX. HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS

achieved. It was also demonstrated that, independently of the size of the objects, any type of object can be documented, in a macroscale perspective or in detail. Regarding the chromatic reintegration tools, both in 2D images and 3D objects, the main tools are the paintbrushes and clone tools. In both cases, despite the low difficulty level, appropriate training is required to edit the images and post-process the models. As with most software, attention should be given to the learning process in the context of specific training. Although it seems easy, learning should be structured so that the results can be achieved. Otherwise, as with real paintings, image distortion may occur during virtual reintegration.

4. CONCLUSIONS All documentation areas referred to in the text, associated to geographic information systems, photogrammetry and computer graphics, have been in application for several years in the cultural heritage context. More recently, advances in computing technologies have enabled the development of high-definition models, extending the application of the tools to a level of detail beyond a simple registry of the objects. With the recent modern photogrammetry it is possible to produce automatic mode models with high degree of realism. Moreover, to register these 3D models in virtual environments, there are countless possibilities for the representation of cultural objects with their photographic textures. 90

Such representations may be associated with evidence of technological objects as well as their degradation phenomena and pathologies. In future work, 3D animations with hyperrealistic scenarios are probably the next frontier of documentation, where the virtual and the real world are entailed. Independently of the techniques used to acquire data for the objects under representation, chromatic reintegration is essential to increase the best results, especially for virtual reconstructions. But, even in digital processing, the colour reconstruction is always a non-original addition. For accurate scientific works “less retouching is more� and the possibilities is always unlimited.


IX. HERITAGE DOCUMENTATION AND 3D RETOUCHING OF VIRTUAL OBJECTS

REFERences [1]

SCHMID, Werner, ed. - GRADOC: Graphic Documentation Systems in Mural Painting Conservation. Research Seminar Rome 16-20 November 1999. Roma: ICCROM, 2000.

[2] PETRESCU, Florian - The use of GIS technology in Cultural Heritage. In Proceedings of the XXI International CIPA Symposium, 01-06 October 2007, Athens, Greece. [3] ASPRS - Manual of photogrammetry. 4a ed. Bethesda: EEUU; 1980. [4] FRASER, C. S. - A resume of some industrial applications of photogrammetry. ISPRS Journal of Photogrammetry and Remote Sensing, n.º 48(3) (1993), pp. 12–23.

[18] GEARY, A. - Three dimensional virtual restoration applied to polychrome sculpture. The Conservator, 28 (1), (2004), pp. 20-34. [19] GAIANI, M. - Color Acquisition, Management, Rendering, and Assessment in 3D Reality-Based Models Construction. In Handbook of Research on Emerging Digital Tools for Architectural Surveying, Modeling, and Representation, Hershey, PA, IGI Global, 2015, pp. 1–43. [20] MAINO, G.; MONTI, M. - Color Management and Virtual Restoration of Artworks. In Color Image and Video Enhancement. Celebi, Lecca, Smolka: Springer, 2015, pp.183-231.

[5] ATKINSON, K B. - Close range photogrammetry and machine vision. Caithness: Whittles Publishing, 1996. [6] KRAUS, K. - Photogrammetry. Fundamentals and Standard processes. Vol. 1. Köln, Germany: Dummler; 2000. [7] CARBONELL, M. - Arquitectural photogrammetry. In KARARA H. M., ed. - Non-topographic photogrammetry. Falls Church, Virginia: ASPRS, 1989. [8] MOULON, Pierre; BEZZI, Alessandro - Python Photogrammetry Toolbox: A free solution for ThreeDimensional Documentation. ArcheoFoss 2011. 6º Workshop Open Source, Free Software e Open Format nei processi di ricerca archeologica, 2011. [9] Arc-Team (Phyton Photogrammetry Toolbox). Available at: http://184.106.205.13/arcteam/ppt.php [27 May 2016]. [10] Autodesk Remake (known as Autodesk® Memento. Available at: https://memento.autodesk.com/about [27 May 2016]. [11] RAMÍREZ-SÁNCHEZ, Manuel; et al. - Epigrafía digital: tecnología 3D de bajo coste para la digitalización de inscripciones y su acceso desde ordenadores y dispositivos móviles. El profesional de la información, sept.-oct., 23, (2014), pp. 467-474. [12] APARICIO RESCO, Pablo. - Arqueología virtual para la documentación, análisis y difusión del patrimonio. El horno de cal de Montesa (Valencia). Colección monografías 2. [s.l.]: Publicaciones Digitales, 2015. (PDF interativo. e-dit-ARX) [13] FIGUEIREDO, César - A Reconstituição Arqueológica: uma tradução visual. Al-Madan Online, IIª série, n.º 20, Tomo 2, 2016, pp. 6-13. [14] Photoshop. Available at: http://www.photoshop.com/[27 May 2016]. [15] ImajeJ - An open platform for scientific image analysis. Available at: http://imagej.net/Welcome [27 May 2016] [16] Blender. Available at: https://www.blender.org/ [27 May 2016]. [17] SANTOS MADRID, José Manuel -El color en la reproducción fotográfica en proyectos de conservación.Revista ph Instituto Andaluz del Patrimonio Histórico, n.º 86, octubre, 2014, pp. 102-123.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

91


92


X

Treatment of lacunae, Gestalt psychology and Cesare Brandi. From Theory to Practice


X.

Treatment of lacunae, Gestalt psychology and Cesare Brandi. From Theory to Practice

Giuseppe Agulli (1)| Nova Conservação, lda. Liliana Silva (2)| Nova Conservação, lda. (1) Giuseppe Agulli; Lisboa; E-mail address: giuseppeagulli80@gmail.com (2) Liliana Silva; Tomar; E-mail address: lilianasilva@ncrestauro.pt

Abstract When one reflects on reintegration of lacunae in a work of art, so many questions arise. In this communication we wish to point out practical solutions found for the treatment of lacunae in some interventions that we have carried out. Color abstraction, toning of support, sfumato, pointillism, tratteggio represents only some of the possible choices. It is not our wish to dwell on techniques, but instead to try to explore the theoretical principles that guide our choices regarding the treatment of lacunae through the analysis of the research by Cesare Brandi that combines his own Theory of Restoration with Gestalt’s Theory of Vision. Concepts such as the respect for the authenticity of the work of art, recognizability and reversibility of an intervention are still milestones for which different technical solutions were developed over time. There is no solution that can be used in a systematic way for every intervention. Each work of art is unique and only through a philological approach of the entire restoration project and a proper implementation of all phases of execution, one can get a correct and compliant image reading.

Keywords Lacunae; Gestalt Psychology; Cesare Brandi; Chromatic reintegration.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

95


X. Treatment of lacunae, Gestalt psychology and Cesare Brandi - From Theory to Practice

1. Introduction The reintegration of lacunae arise lots of questions. In this article, we wish to point out some of the practical solutions found for the treatment of lacunae in its material and aesthetical components. In the first case, we have a gap of material, a physical loss, while in the second case we have a lack of vision or an interruption of continuity of the image. Concepts such as the respect for the authenticity of the work of art, recognizability and reversibility of an intervention are still milestones for which different technical solutions were developed over time. There is no solution that can be used in a systematic way for every intervention, but a scientific and critical approach of the problem. Through the analysis of the research undertaken by Cesare Brandi, which combines his own Theory of Restoration with Gestalt’s Theory of Vision, we will try to explore what are the theoretical principles that guide our choices, regarding aesthetic presentation.

2. Theoretical Principals Each work of art is unique and only through a philological approach of the entire restoration project and a proper implementation of all phases of execution, one can get a correct and compliant image reading. As noted by Dr. Marco Ciatti [12] (Art historian, director of Painting Conservation Department and Superintendent of the Laboratories of the Opificio delle Pietre Dure, in Florence) 96

“all stages of restoration are not independent from each other, but all must answer to the interpretation of the work of art, from the cleaning to the consolidation grouting”. “The filling is a critical step and reconciles the need for structural and aesthetic characteristics. Just think of a perfect reintegration performed on a grouting that has not been well-accomplished, in the end gives an aesthetically unsatisfactory result.” Cleaning a polychrome surface must already predict and account for what will be the integration problems of the lacunae”. A solid and specific plan, as well as a proper execution of all the phases of the operation, is the basis of a “good reintegration”. The reintegration in works of art is certainly the most cited theme throughout the theoretical treatises and, therefore, the most sensitive and difficult to be translated into practice. One of the oldest compilation of methods of restoration was carried out by Cesare Brandi [10], who perceived that the principles of Gestalt could be used for the purpose of restoration and conservation, especially regarding the aesthetic treatments. The first great Gestalt revolution was as follows: “The whole is more than the sum of its parts,” that is, the reality is read not as a sum of individual sensations, but as a whole entity. In Brandi’s opinion, this can be translated into “The Potential Unity of the Work of Art” [3]. The work should be considered as a whole and only successively be composed of parts. The sum of all elements forms the whole. The whole is an element itself, although it is composed of parts. For instance, a mosaic is made up


X. Treatment of lacunae, Gestalt psychology and Cesare Brandi - From Theory to Practice

of many coloured tiles in juxtaposition, but the image formed in our minds and in our consciousness is that of a whole.Moreover, through reintegration, one must restore the “potential unity” of the work without disregarding two fundamental principles: the principle of recognition and the principle of reversibility. Studies on Gestalt psychology clarify the mechanisms that affect visual perception and show how to eliminate or mitigate the disturbance created by the lacuna. Visual perception follows certain rules. As noted by Edgar Rubin (Danish psychologist) [2], in 1921: A) The enclosed surface tends to be seen as a figure, while the unlimited enclosure tends to appear as a background; B) A figure is distinguished by the characteristic of having a shape, an outline, a defined size, to have an advanced position and being able to emerge. On the contrary, the background appears amorphous, undifferentiated and remains in the background compared to the figure. Kurt Koffra, in “Principles of Psychology” [2], explains that a figure is defined by a border, which, however, gives shape to its internal and not to the external aspects.A linear closed border belongs to the enclosed figure and segregates it from the surrounding field. The lacuna, or a chromatic interference, being included in the painting, is obviously smaller than the painting itself and generally has convex margins. It is evident that it will assume the role of the figure rather than the background. From the moment that the lacuna is registered in our

minds as a foreign element, it ceases to be part of the preparation and becomes a figure on the painting. In fact, what is registered is the figure and not the background [11]. The new figure becomes the protagonist and distracts us from the painting, leading to devaluation, relegating it into a background role. “Therefore it would be better if the lacunae were at a different level than the surface of the image, and where this is not possible, it would be necessary to graduate the tone of the lacuna in order to create a spatial situation different from the tones expressed in the incomplete picture” [3]. In the Gestalt theory, there are many laws that explain how we see images and that help us to understand how we may eliminate the interference of lacunae ([1], [2], [4], [6], [7], [11]). We will consider some of these laws and apply them to our case studies. The law of proximity and the law of similarity explain that there are elements whose proximity creates images of rows or columns even if these do not exist in reality. The lacunae on a painting may create a form which disturbs the correct perception of the composition. In figures 1 and 3, we can see how the lacunae become a figure, not only because there is a smaller distance between them, but also because they can be perceived more cohesively and, thus, facilitate the division between them and the painted area. The law of common fate and the law of continuity of direction explain how the longitudinal progress of the lacunae tends to unify them through a transversal direction or orientation or movement.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

97


X. Treatment of lacunae, Gestalt psychology and Cesare Brandi - From Theory to Practice

Law of closure: the lines that form the closed figures tend to be seen as formal units. Our mind is prepared to provide additional information to close a figure, therefore, the closed margins or those that tend to unite, impose themselves as joining figural units on the open ones. Law of past experience: elements that are part of our past experience usually associate themselves and, so, tend to join in forms. This law shows that not all lacunae need to be reconstructed.

3. Case Studies 3.1. “Quarto da Menina” at São Boaventura street in Lisbon.

The ceiling was in a poor condition: there were abrasions and cracks along the planks of the support; the original preparatory layer was not firmly cohesive, especially at the edges; the plaster used during a previous restoration was completely detached from the support; the slight layer of original paint presented blistering and lifting. Here, two different types of lacunae were identified: 1) abrasion of the painting layer, leaving the underlying layer of paint in full view, often of a lower tone in respect to the final one; 2) total fall of the colour and preparation layers, creating a strong visual disturbance and leading to a negative interpretation of the work of art, i.e. to a misunderstanding of the relationship between figure and background. 98

In the first case, the solution was to lower the chromatic disturbance, giving what was lacking to the original context, through the “tratteggio” technique. In the second case, the concept of intuition of Cesare Brandi (that identifies the important factor of space, the stratigraphy of the lacunae) was applied, leading to an automatic acknowledgement of what has remained compared to what was missing. The lacunae, placed on a different level from the image, is conceived somehow as a foreigner to the figurative painting, differentiated from the pictorial context and conducted to a nonoriginal level. The interpreted and perceived simplification could be resolved through an innovative spatial methodology (figures 1, 2).

3.2. Triumphal Arch of Charola of Convent of Christ, in Tomar

In the conservation and restoration treatment

of the mural paintings at the triumphal arch and soffit, the condition and execution technique (oil painting over an extremely subtle layer preparation applied to the wall, built in limestone blocks) has conditioned the intervention methods, particularly in the aesthetics restitution phase. Taking into account the existence of a large amount of lacunae in the colour layers interfering directly with the correct reading of the image - in what regarded the aesthetic intervention, it was decided to reduce the visual interference, but never leaving back the fundamental theoretical principles.


X. Treatment of lacunae, Gestalt psychology and Cesare Brandi - From Theory to Practice

In this sense, the lacunae treatment was preformed according to the principles of reversibility and recognition and in compliance with the laws of visual perception, in order to achieve the reduction of optical disorder and restore a good reading of the artwork. The reintegration method chosen was the velatura for the smallest lacunae, which were closed with colors near to the original tones and, in the larger, cold tones were applied, in order to lower the tone of the support and reduce its lightness. Some areas were treated with sfumato techniques in order to perceive the forms without creating a border. This option is based on the following example: a yellow colour is more evident as a form when inserted in a defined border. If we try to eliminate this border, the yellow circle is less evident and the luminosity changes ([5]). In the areas filled up with a red layer, in order to reduce its visible incidence, soft velatura were applied using a complementary colour. In paintings, two colors are called complementary subtractive, if, when mixed together, they desaturate each other, until you achieve a grey tone (figures 3, 4) [4].

• •

• •

the metal alloy. Dark patina: caused by deposition of pollution and atmospheric dust. “Zebra” corrosion caused by water flow - especially along the horse sides into its abdomen. Efflorescence of salt: localized phenomenon of corrosion. Stains caused by the leaching of patinas.

In this case, the aim was to re-establish a correct balance between all of this optical interference and a correct read of the whole image. In the pictures below one may see how lighter green areas take our attention and do not allow the reading of the feathers. During the cleaning operation the chromatic disturbance was reduced but it wasn’t enough. Through application of velatura, we were able to create a correct visual interpretation of the statue (figures 5, 6).

3.3. Equestrian Statue D. José I, Praça do Comércio, in Lisboa

The equestrian statue D. José I is made of a metal alloy (admiralty brass), composed by copper 80%, tin (2%), zinc (12%) and lead (3%). During our intervention, we have recognized different kinds of alteration that interfered with the correct interpretation of the volumetric and chromatic values of the image:

Figure 1. “Quarto da Menina” at São Boaventura street in Lisboa, before the intervention.

• Green patina: product of alteration of III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

99


X. Treatment of lacunae, Gestalt psychology and Cesare Brandi - From Theory to Practice

Figure 2. “Quarto da Menina” at São Boaventura street in Lisboa, after the intervention.

Figure 5. Equestrian Statue D. José I, Praça do Comércio, in Lisboa, before the intervention.

Figure 3. “Triumphal Arch of Charola of Convent of Christ, in Tomar, before the intervention.

Figure 6. Equestrian Statue D. José I, Praça do Comércio, in Lisboa, after the intervention. Figure 4. “Triumphal Arch of Charola of Convent of Christ, in Tomar, after the intervention.

100


X. Treatment of lacunae, Gestalt psychology and Cesare Brandi - From Theory to Practice

4. Conclusions

Achnowledgements

According with Dr. Serena Sechi, we also think that:

To our colleagues of RECH 3, for the invitation to participate in the third encounter on the problems and methodologies of retouching.

“Fruition, in our cosmopolitan society, cannot be differentiated according to personal tastes and national or regional borders. Rather it should ensure an interpretation of the work of art, free from any particular analyses and free from debatable aesthetic treatment. So we should take the road towards the normalization of pictorial reintegration through perception theory. The enjoyment of the artwork is based on the laws of vision and any treatment of reintegration should be chosen depending on the characteristics of perception. Optical physics and the rules of visual perception can help us finding a correct way for the aesthetic treatment. This should result in a third parameter: the good perception of reintegrated intervention. The study of perception permits the acknowledgement of the mechanisms that affect vision and allows you to take into account the particular characteristics of the various methods of reintegration.” [9].

To the authorities that allowed the development of these works. To Nova Conservação’s team remembering that we are parts of the same engine that can work well only if all the pieces are working properly. We would like to emphasize that the current study is in line with the contribution made by Dr. Serena Secchi who, in the course of her dissertation for her diploma at Istituto Superiore Conservazione e Restauro, entitled “The pictorial reintegration, theory and method of intervention was in fact the aesthetic treatment of the lacuna”, dealt with this theme in an exhaustive manner. To Anna Marcone, that passed away this winter, and left us her precious teachings that will always remain with us.

We can select the reintegration treatment that best suits the work of art, without resorting to reasons of subjective and debatable taste. So, the choice for a particular type of reintegration must be based exclusively on the intense study of the visual needs of the work of art.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

101


REFERences Book: [1] AAVV, “La percezione visiva”, a cura di F. Pueghè, N. Stucchi, A. Oliviero, Utet, 2003. [2] Arnheim R, “Arte e percezione visiva”, Milano 2003 [3] Brandi C. “Teoria del Restauro” 1961. [4] Frova A., “Luce colore visione”, Bur, 2004. [5] Kandinsky W., “Lo spirituale nell’Arte”, Bompiani, Milano 1993. [6] Kanizsa G., “Grammatica del vedere”, il Mulino, Bologna, 1980. [7] Maffei e Fiorentini, “Arte e cervello”, Zanichelli Editore, 2003. [8] Mora P., Mora L., Philippot P., “La conservazione delle pitture murali”, Compositori, 2001. [9] Sechi S., tesi di diplomaIstituto Superiore Conservazione e Restauro, “La reintegrazione pittorica, teoria e metodo di intervento Stato di fatto del trattamento estetico della lacuna”.

Scientific article: [10] Brandi C. 1963, “Il trattamento delle lacune e la Gestalt psicologie”, in The aestethic and historical aspects of the presentation of damaged pictures’. In Studies in Western Art, Acts of the twentieth International Congress of the History of Art, Vol.4: Problems of the 19th and 20th centuries, ed. M. Meiss, Princeton University press, Princeton, New York: 146-151. [11] Caronna A. 2005. “L’eredità della Gestalt e la Teoria di Cesare Brandi”, KERMES XVIII (57): 57-64. [12] Ciatti M., “le fasi finali nel restauro tra teoria e pratica, alcune riflessioni” in atti del convegno di Trento 2009 2010, CESMAR7.

102


XI

Different hands, different paintings, one retouching the conservation project of the Funchal’s Cathedral altarpiece


XI.

Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

Glória Nascimento (1,2), Sofia Gomes (2), Carolina Ferreira (1,2), Joana Júlio (2,3) Mercês Lorena (2), António Candeias (2,4) (1) Faculdade de Belas Artes, Universidade de Lisboa, vgloriaanascimento@gmail.com; carolinaferreira80@gmail.com (2) Laboratório José de Figueiredo, Direção – Geral do Património Cultural, sofia.machado.g@gmail.com; merceslorena@gmail.com (3) SELO – Conservação e Restauro, Lda., joana.julio@gmail.com (4) Laboratório HERCULES, Universidade de Évora candeias@uevora.pt

Abstract The aim of this article is to present and discuss the retouching methodology followed during the conservation and restoration intervention of the twelve paintings of the altarpiece of Funchal’s Cathedral, situated in Madeira Island, Portugal. Being an in situ intervention, new challenges have emerged during the reintegration process, imposed by the location of the 16th century panels in the altarpiece structure, the brightness characteristics of a religious building as well as the constraints of working on a scaffold. However, this proved to be an advantageous situation as it made possible to analyse the set of paintings, allowing to establish guidelines for the whole process. The reintegration method is the result of an overall analysis on the different levels of cleaning, which is a major factor in the definition of techniques, materials and desired levels of retouching in each one of the paintings. Retouching allowed restoring the visual reading of each individual painting, despite the different levels of dirt and of the existence of overpaintings, making it possible to recover the iconographic reading of the altarpiece set as closer to its original state. On account of the particularities of the pictorial whole of the Funchal’s altarpiece, it is considered that this is a case of particular relevance as it contributes with a new perspective for the discussion on the importance and the ethical limits of the chromatic reintegration in painting sets, as well as in paintings exhibited in religious buildings.

Keywords Funchal’s altarpiece; painting set; in situ; retouching.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

105


XI. Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

1. Introduction Ordered by King Manuel I, this polyptych is formed by twelve paintings, inserted in a gilded carved structure with small sculptures [1]. This is the only Portugal’s remaining monumental altarpiece from the 16th century with paintings and sculptures that is preserved in its original place. The oil on panel painting set, that can be dated between 1512 and 1516 [2], has the average dimensions of 200 cm by 94 cm (height and width) and are distributed along three levels: Lower level – Eucharistic theme: Abraham and Melchizedek (1); The Last supper (2); The mass of Saint Gregory (3); The gathering of the Manna (4). Middle level – Virgin’s life theme: Annunciation (5); Nativity (6); Pentecost (7); Virgin’s ascension (8). Upper level – Christ’s life theme: Christ praying in the garden (9); The Way to Calvary (10); The descent from the Cross (11); The resurrection (12), (see example in Figure 1 below).

During the centuries this painting set was object of several restorations made for iconographic purposes, during loans to exhibitions or due to conservation problems. As a result, the paintings have considerable reading and degradation differences. Considering this situation, the painting set was divided in three groups: 1 - Group of four paintings, loaned to the 1st Portuguese Primitives Exhibition in Lisbon and restored in 1940 by Fernando Mardel, in the José de Figueiredo Laboratory: Abraham and Melchizedek (1); The gathering of the manna (4); Annunciation (5); Christ prying in the garden (9). 2 - Group of four paintings with the varnish heavily oxidized and a thick layer of dirt on the surface: Nativity (6); Pentecost (7); Virgin’s ascension (8); The resurrection (12). 3 - Group of three paintings with total or partial over painting: The Last supper (2); The mass of Saint Gregory (3); The descent from the Cross (11). Therefore, only after the conclusion of the cleaning proceeds was possible to analyse and characterize the original paint surface and define the retouching methodology. The conservation and restoration project developed in situ, with the Cathedral opened to the cult and to visitors, aimed to restore the visual and material integrity of the altarpiece1.

1

Figure 1. Location of the paintings in the altarpiece, before the conservation intervention. Altarpiece drawing ©Filipa Abrantes (DRAC/DSMPC), painting location scheme ©Sofia Gomes (LJF-DGPC).

106

The Funchal’s altarpiece conservation and restoration project was carried out under the framework of the consortium created by the Government of the Autonomous Region of Madeira, through the Directorate of Museums and Cultural Heritage (DARC/DSMPC), the Diocese of Funchal and the World Monuments Fund – Portugal. The technical coordination of the project was ensured by the José de Figueiredo Laboratory (General Directorate of Cultural Heritage) and HERCULES Laboratory (Évora University), which together defined the conservation and restoration methodology.


XI. Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

In this article it will be presented and discussed the retouching methodology applied, concerning the reversibility of the materials and techniques applied, as well as the differentiation between the original paint layer and the retouching.

2. How

to define methodology?

a

retouch

Considering that the main goal of the retouching was to return the global reading of this twelve paintings, individually and as a group, it was also important to ensure the Eucharistic utility of the altarpiece, as it is located in a Cathedral that is open to cult. From a global point of view, the twelve paintings included in Funchal’s Cathedral altarpiece can be characterized by the different thickness and texture of the paint layers. In some areas, like the flesh tones, the paint layer was very thin, allowing to see the underdrawing. In these areas the forms are defined by the lines of the underdrawing, while in others zones the paint layers were opaque and thick, as it is for example in the garments (see example in Figure 2 below).

Figure 2. The Way to Calvary painting detail where is possible to see the difference of thickness and texture of the paint layer, before cleaning. ŠRoberto Pereira (DRAC/DSMPC).

This particularity has an enormous influence in the selection of materials and retouching technique as well as the level of reintegration defined. The desired level of retouching in each painting, as well as for the set, was based on the result of a global analysis of the conservation condition of the original paint layers. The retouching done in each painting was adjusted to the retouching needs of each one of the others paintings, with the objective of attaining a global and uniform chromatic and formal reading [3].

2.1. Retouching challenges

The conservation and restorations of the painting set project was developed in situ, avoiding moving the painting from its original exhibition location, minimizing the damages during the removing from the altarpiece structure and the changes in environmental conditions (temperature/relative humidity) III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

107


XI. Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

that paintings would have been subjected to during the transportation. In fact, working in situ with the paintings in their original location in the altarpiece was very important during the retouching process because it allowed to establish reading lines and to compare the retouching developments with the other paintings. In a twelve painting altarpiece, each painting has specific retouching needs, that results from surface damages, losses and wear, as well as over cleaning. Understanding each painting was as important as to analyse the painting set, approaching the retouching as a global procedure, looking to the paintings around and comparing the damages and retouching possibilities.

the losses already filled with a white filling paste. After applying an isolating coat of Dammar varnish that creates a barrier between the original surface and the new retouching layers, the conservation team retouched the damaged areas with powder pigments in Dammar varnish, as it is described below: First phase – In

filled paint losses areas, the filling material was covered with a plain opaque layer of Talens® gouache, used as a colour base for the final retouching. This first layer guaranteed a good integration of the paint losses and allowed the application of a new layer of colour using varnish as a medium (see example in Figure 4 below).

Achieving the same retouching levels in the twelve paintings, with different damages and levels of degradation, was the biggest challenge.

2.2. Retouching

Define a retouching methodology was a challenging factor for the team work, because each conservator has distinct approaching, depending on their individual experience. As each conservator has individual way to construct the colour and personal retouching levels criteria, the retouching methodology was discussed by the conservation team in order to reach a consistent result. The selected retouching methodology was a two-step procedure, using different materials in each one. The retouching started using gouache, a water soluble material, to integrate

108

Figure 3. Detail of Abraham and Melchizedek painting during the first phase of retouching. ©Sofia Gomes (LJFDGPC).

The retouching with powder pigments in Dammar varnish was made on the first retouching layer, in the filling areas and integrating worn or over cleaned areas. Above the plain opaque layer, it was made a mesh of small dots and vertical lines that creates the perception of the surrounding colour. With this technique the retouching areas are

Second phase –


XI. Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

imperceptible when observed from a distance, but distinguishable with a closer observation, (see Figure 5 below).

retouching process.

3. RESULTS and Discussion The reversibility was one of the main concerns during this project, and it was also considered in the choice of materials to be used.

Figure 4. Detail of Abraham and Melchizedek painting during the second phase of retouching. ©Sofia Gomes (LJF-DGPC).

In the second phase, as for the first varnish coat, the retouching medium was prepared dissolving 200 grams of Dammar resin in 1000 mL rectified turpentine. The Dammar resin, being less stable than the synthetic options now available, Tinuvin® 292 was added as a stabilizing additive. Tinuvin® 292 is a Hindered Amine Light Stabilizer that can be added to varnishes to slow the degradation caused by UV light. The percentage added corresponds to 3% of the weight of the resin, and does not interfere with the percentage of added solvent [4]. The selection of Dammar varnish as medium for the retouching with powder pigments was based on its optical and handling properties. As this natural varnish has been used for a long time as a medium for powdered pigments its characteristics are well known, making it possible to have better control during the

The chosen retouching methodology allowed the conservators to work per layers, as each one of them can be removed using different solvents. This methodology guarantees that in the future, each one for the retouching layers could be removed without damaging the underlayer or the original painting surface. Nowadays, reversibility is a requirement of all restoration materials, which should be able to be removed without damaging the original [5]. The decision to use Dammar varnish as medium for the powder pigments during the second phase of the retouching was a decision based on the material properties of the varnish and the compatibility with the varnish coat applied on the painting before and after the retouching. The published literature on chemical analyses of the physical properties of Dammar resin demonstrated that this natural resin has a fast degradation process in the presence of UV light, resulting in the loss of solubility [6]. However, it is possible to slow the varnish alteration adding a UV blocker as Tinuvin® 292 or removing the UV light sources. The lightening inside the Cathedral is provided by an electric system, because the 16th century building has small window that does not let through enough sun light.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

109


XI. Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

However, with the installation of a new UV-free lamp lightening system in the main chapel and by adding a UV blocker in the varnish, it is possible to control the light degradation, guaranteeing Dammar varnish stability and delaying degradation. Apart of the complexity of retouching a painting set divided in three different levels in an eight meters high altarpiece, and the technical limitations of working in a scaffold inside an opening to cult Cathedral, work in situ has the advantage of maintaining the paintings in their original place and making possible that in all working stages the painting team could have a global look to the painting set (see Figure 5 below).

4. CONCLusions Considering the needs of the visitor and the visual function of these twelve paintings, the aim of the retouching was to recover the ‘original’ reading of the pictorial set as closer to its ‘original state’ as possible. The retouching allowed to minimize the disturbance caused by losses and to restore the altarpiece functionality, keeping the historical and cultural memory. The results obtained, being evident with closer observation but unnoticeable when observing the whole object, were very satisfactory. Considering the characteristics of the retouching material, as the Dammar resin, a new lightening system was assembled in the main chapel. In fact, a good lightening system, using non UV lamp, is essential to control the light exposition and to avoid the degradation caused by the light. In conclusion, the retouching applied allowed to restore the visual reading of each individual painting, despite the different levels of dirt and of the existence of overprinting’s, making it possible to recover the iconographic reading of the altarpiece set as closer to its original state.

Figure 5. Paintings in the altarpiece, after finishing the project. https://www.wmf.org/project/funchalcathedral, [11 December 2015].

110


XI. Different hands, different paintings, one retouching The conservation project of the Funchal’s Cathedral altarpiece

REFERences [1] CATEDRAL DO FUNCHAL, Official website of Monumentos Available at: www.monumentos.pt/Site/APP_PagesUser/ SIPA.aspx?id=5015 [11 December 2015]. [2] TEIXEIRA, Luís – O Retábulo-mor da Igreja Grande do Funchal. Monumentos nº 10. Lisboa: Direcção-Geral dos Edifícios e Monumentos, 2003, pp. 50-55. [3] CALVO MANUEL, Ana – Conservación y retauración Matariales, técnicas y procedimientos de la A a la Z, Barcelona: Ediciones del Serbal, 2003 [4] CHERCOLES, Ruth; DE TAPOL, Benoît; ORDOÑEZ, Ana; DOMEDEL, Lourdes – Low molecular weight varnishes. Interview to E. René de la Rie, National Gallery of Art, Washington, DC. Ge -Conservatión n.º2 (2011), pp. 33-42. Available at: http://ge-iic.com/ojs/index.php/revista/ article/view/40/pdf [11 December 2015]. [5] CONTI, Alessandro – A History of the Restoration and Conservation of Works of Art, 2007, English Translation by Helen Glanville, Milan: Elsevier Ltd, 2007. [6] DIETEMANN, Patrick; HIGGITT, Catherine, KALIN, Moritz; EDELMANN, Michael J., KNOCHENMUSS, Richard, ZENOBI, Renato – Aging and yellowing of triterpenoid resin varnishes Influence of aging conditions and resin composition. Journal of Cultural Heritage, nº 10, 2009, pp.30 – 40. Available at: http://andbeyond.ch/Dissertation/Publications/J_Cult_ Herit_2009_10_30-40.pdf [11 December 2015].

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

111


112


XII

Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces


XII.

Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

Leonor Loureiro (1), CĂĄtia Silva (1), Ana Catarina Rosa (1) (1) Instituto PolitĂŠcnico de Tomar; Quinta do Contador, Estrada da Serra, 2300-213 Tomar;

E-mail address: leonorloureiro@ipt.pt ; katiavss_21@hotmail.com; catarina.bizi@gmail.com

Abstract Preserving privately owned old photographs might be challenging. Being paper-based with a gelatine coating, with usually different length and width proportions, they suffer poor handling and improper housing. Easily damaged by being forgotten in the back of a chest of drawer, or even inside shoe boxes, they show problems as creases, folds, fractures, finger prints, fungi attacks, image fading and loss, paper abrasions, lack of paper cohesion and paper losses. Conservation and restoration treatments applied to these objects vary in consonance with the preservation problems they show and the type of materials and features they present. In all cases brought so far to the Paper Conservation Laboratory of the Polytechnic Institute of Tomar, the challenges were how to create an identical and proper surface with Japanese papers, to enable Schmincke Horadam watercolours chromatic reintegration. The most difficult problem to solve was which chromatic reintegration technique should be used, particularly in photographs with an embossed paper surface (a honeycomb geometry similar surface), if an undertone should be used and what colour tone, and how to apply the watercolour veiling on the original paper without damaging the original photograph. This paper intends to show the examples, difficulties and solutions encountered during the chromatic reintegration operation on severe damaged 20th century monochrome photographs, so to achieve a result that would satisfy both owners and conservators.

Keywords Chromatic reintegration; Black and white photographs; Embossed surface; Retouching, Watercolours, Photography conservation. III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

115


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

1. Introduction A set of four monochrome paper photographs from the 20th century, belonging to three Portuguese private owners, were proposed to be conserved by the Instituto Politécnico de Tomar (IPT), at the Paper Conservation Laboratory (LCRDG). Numbered from #1 to #4, they showed different sizes, different paper support qualities, possible gelatine photographic emulsion, diverse sensitive brightness, and possible baryta layer, feasibly making them of the same photographic process. Generally they showed surface dirt, tears, folds and creases, wrinkles, image fading and colour changes, stains and surface deterioration, previous interventions and different dimensions lacunae on the surface and on the paper support. The photographic processes identification and identical preservation problems were adamant to the proposed intervention itself: general surface cleaning, flattening, tears and creases consolidations, lacunae infilling, chromatic reintegration and housing.

1.1. Historical context

Photographic material combines three layers with different functions, which interact with each other. The first layer is the support of the superior layers, offering mechanical resistance to them. The second layer gives a smoother finish, and after the 1950’s it also incorporated optical brighteners. The third and last layer is the binder, a transparent and viscous material that allows the dispersion of the image formatting substance, letting it to adhere to the support.

116

Historically a huge variety of primary materials have been used as support for an image forming material: metal, glass, paper and plastic, with today’s resin papers (RC; two-sided plastic coated to facilitate processing and reduce winding) being very much disseminated [1] [2]. The binding layer is a fundamental constituent for the image formation. Most common are albumen, collodion, and gelatine, and the stability of these protective layer is essential to ensure a long lasting image. Albumen has prevailed in paper photographs through most 19th century, and gelatine prevailed in the last 100 years [2]. Developed-out papers (DOP) emerged around 1880, only to be subdue in the 1970’s by the chromogenic process. The arrival of the small format negative was one of the factors that led to the growing use of DOP photographs, as well as the possibility of being printed under artificial light. DOP is a paper with an industrial baryta layer, with different paper weights, colours and surface appearances. Its production is divided in three different emulsion compositions: silver chloride (gelatine and silver chloride emulsion, commercialized until the 1960’s), silver bromide (gelatine and silver bromide emulsion, more sensitive to light, so artificial light can be used, and therefore shows slightly bluish cooler neutral hues), and silver chloride bromide (gelatine and silver chloride bromide produce a neutral hue image, warmer than silver bromide, due to the revelation process). The decline of the monochrome photography was caused by the rapid development of colour photography in the 1960’s and 70’s [1].


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

1.2. Photographs identification

To identify 19th and 20th century photographs (positives) it is commonly used Reilly’s 1986 methodology [2]. The diversity of historic and contemporary photographic processes, as well its structural complexity, demands technical knowledge from the conservator in order to correctly identify these documents. Both naked eye and 30x stereo microscope observation allow the positive verification of emulsion layer, hue, presence or absence of baryta layer, visible or not fibres of the paper support, letting a process identification of whether it is composed by one or more layers [3]. Crossing visual analysis data with bibliographic information can led to fairly reliable conclusions. The correct identification of the photographic process and its structure (support materials, binding and image forming material) determines the conservation treatment and final housing. These four objects where observed through a 45x compound microscope, and follow both Reilly’s guidelines and Kodak identification chart flow [1] [4] [5]. With no visible paper fibres, a neutral hue image with silver mirroring and no visible paper fibres, it was concluded that the four photographs where DOP, three layer photographs with baryta, gelatine binder, and a shiny silver salt surface with variations between them were in shine, hue and paper support. Photo #4 was the only positively identified as KODAK Polylure Y (Silk, high lustre), characterized for its gloss and small dots special embossed texture (Figure 1) [6] [7].

Figure 1. Photo #4 honeycomb surface detail.

2. Description and preservation state The four photographs were all monochrome baryta DOP’s from the 20th century. Photo #1 is a proof entitled “Fotografia de Joaquim Bagorro Sequeira” with no support mark whatsoever, and probably dates from the 1940’s. In its verso shows a photographer purple stamp “Fotografia Leitão- Portalegre, Cliché nº 18571”. The creamy colour paper measures 228 x 168 mm, and has its original margins cut straightforward. Reasonably conserved, it has yellowed due to paper acidity and oxidation, which makes this type of support fragile. Wrinkled, it showed Lepisma spp. attack all over its surface, and an enormous surface lacunae on the paper support, the chin area of Mr. Joaquim Sequeira. (Figure 2). This had been previously “restored” with black pencil by its wife, in order to disguise it, and looked like a dark stain.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

117


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

Figure 2. Photo #1 detail after cleaning and before conservation.

Photo #2 is a proof entitled “Fotografia do bisavô Remígio”, with no support mark, dating Figure 3. Photo #2 before conservation. probably from before 1930’s. The biggest one, it measures 390 x 300 mm, and 0.018 mm thickness. The creamy colour paper has its original margins straightforward cutted. Extremely damaged, it was torn into different size pieces (Figure 3) by the wife of the man in the photo, when she discovered the amount of debt he had left her after his death. It was secretly rescued by their daughter and kept curled into a cylinder. Friable, with silver mirroring, tears, folds and creases, wrinkles and foxing, stains and oxidation, tape and lacunae, it was the most damaged photograph in the set.

Figure 4. Photo #3 before conservation.

Photos #3 and #4 are a set of their own from the 1950’s. Photo #3, a proof entitled “Retrato de Jovem Senhora” (Figure 4), shows a faintly embossed company mark on the right corner of the paper support, were it can be read “Simas, R. da Beneficência (Ao Rego)”. The smallest of

118


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

the set, it measures 127 x 84 mm, and 0.030 mm thickness. The beige colour paper has scissors cut margins. On its verso, handwritten in ballpoint pen, one can read “Fotografia tirada a 20 de Dezembro de 1952 Recordação de Emília Rosa Portinha para a minha pessoa José Nunes 16-11.1953”. Reasonably preserved, it showed silver mirroring and minor surface damages, especially in the upper left corner, and minor lacunae.

followed by the lacuna filling with pre-toned 42 g/m2 Mulberry Japanese paper, because of its resistance and similarity with the original. In both cases the adhesive used was 4% Tylose MH 300, which has a good adhesion power, transparency, flexibility and reversibility. Finally, the technique used for chromatic reintegration was a differentiated one, applied using the method of Pointillism. As watercolour is commonly used in conservation and restoration Photo #4 is a proof entitled “Retrato de um of graphic materials, as a material that allows Jovem Senhor”, and shows a strong embossed its removal, but also creates a similarity with company mark on the right corner of the paper the original coloured materials, it was chosen support, equal to Photo #3. The beige colour the Schmincke® Horadam® watercolour Ivory paper measures 137 x 84 mm, and 0.029 mm Black (ref. 780), using #0 e #1 fine brushes. thickness, and shows its original margins wave In Photo #1, by the end of the reintegration cut. On the verso a purple stamp can be read process, a contrast was still notorious between “Foto Simas Lisboa, Rua Beneficência, 62, the reintegrated lacunae surface and the TELEF. 74179 – Conservamos todas as chaves.”, original surface. This was due to the nonplus “584692” handwritten in ballpoint pen. Very existent surface sheen in the Mulberry paper, damaged and fragile due to high humidity levels which a photograph has due to the gelatine. To overcome this, the entire lacunae area where it had been kept, it showed fingerprints was redone: firstly by removing the chromatic and other stains, oxidation andacidification, reintegration with a cotton swab and distilled emulsion wear and loss, wrinkles and small water; secondly by applying a paste of CF11 tears. Whatman Paper Powder nº 4021050 mixed with 0,5 % Tylose MH 300 on top of the Mulberry paper. This new surface was smoothed by passing a bone folder on top of a piece of Reemay® and left to dry. The result was a 3. Conservation methodologY smoother and shiny surface, levelled to the photographic surface, and better disguising 3.1. Photo #1 Methods and Discussion the joint areas. The chromatic reintegration Photo #1 surface was brush cleaned with soft work continued, with special attention to its brushes, and the black stain was removed with a concentration accordingly to light and dark hue white eraser and circular movements, avoiding transitions. touching the original. The central lacuna was consolidated with 9 g/m2 Tosa-Tengujo Japanese paper, due to its transparency, 3.2. Photo #2 Methods and Discussion flexibility and strong fibres. This action was Photo #2 was extremely curled, dehydrated III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

119


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

and friable, so it posed a cleaning problem. It previously needed to be slightly humidified and sufficiently flatten in order to endure the surface cleaning procedures. It was used the same cleaning action of Photo #1, followed by the tape removal with a #15 scalpel blade and thin tweezers. This was performed with the photograph verso up, and the blade in 180º position, placed between the paper and the tape, so to allow its careful removal bit by bit without cutting the original. Residues were eliminated with the help of a Staedtler eraser pencil, applied slightly with circular movements. The fragments consolidation was performed again with Tosa-Tengujo 9 g/ m2 Japanese paper, and the gaps filled also with pre-toned 42 g/m2 Mulberry Japanese paper, both applied with 4 % Tylose MH 300. The difficulties arise in the torn areas that were more fragile, creased and difficult to disguise, so occasionally some paper fibres needed to be inserted in torn areas, filling minute lacunae. In the chromatic reintegration, it was also applied the Pointillism technique using Schmincke® Horadam® watercolours (more vivid colours), in this case Ivory Black (ref. 780) and Walnut Brown (ref. 652), plus with Winsor & Newton® Cotman® Sepia (ref. 0301609) watercolour (duller shade), all due to their closeness to the warmth of Photo #2 hues. Without knowing for sure what image existed in the photograph, and so to avoid strange reconstitution situations in the two biggest lacunae, it was decided to create a colour degrade of shapes (Figure 4), as this if they were fading, thus not giving a concrete colour formality.

120

Figure 5. Photo #2 Chromatic reintegration detail.

3.3. Photos #3 & 4 Methods and Discussion

Photos #3 and #4 needed also to be cleaned, humidified and flattened, consolidated and infilled, and reintegrated. In these cases, for the surface cleaning a soft white eraser bar was used in the verso, with circular movements, and Smoke Sponge both in recto and verso, with tap movements. For the humidification, a mini chamber was constructed with a plastic box bottom (Figure 6). A soaked blotter was put inside and the inner raised with a hard plastic perforated board, to allow humidity flow but not in direct contact with the photographs. The photos were put on top, protected by a Hollytex, and the whole was covered with a Melinex sheet. After a couple of hours the photos were sufficiently humid to allow flattening between a sandwich of Hollytex, dry blotters, board and small weights. Consolidation was done with 5 g/m2 Spider Tissue Japanese paper, and lacunae infilled with 36 g/m2 Kitakata Japanese paper, both applied with 4 % Tylose® MH300. Occasionally, paper fibres were applied in some slightly open tears and small lacunae. In the chromatic reintegration, both Pointillism and Mimetic techniques were used. Firstly, a thin wash was applied, to slightly match the original. Ivory Black (ref. 780) and Raw Umber (ref. 662)


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

Schmincke® Horadam® watercolours were used, as well as Winsor & Newton® Artist’s® Sepia (ref. 609) e Vandyke brown (ref. 676). In both cases, the biggest problem was posed by Photo #4 due to surface embossing and extensive surface lacunae. This were disturbing of the object reading, therefore being necessary to use a very thin LG nº 10/0 brush to allow a more controlled watercolour application.

Figure 6. Humidification chamber for photos #3 and #4.

Finally the photographs casing (Figure 7) was done with a 1.50 mm thickness TimeCare mounting board window on front, and a 1 mm thickness Premier white-grey board back, both having a 3% calcium carbonate buffer and pH 8.5.

Figure 7. Photo #4 before and after conservation.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

121


XII. Chromatic reintegration of 20th century monochrome photographs showing plain and textured paper surfaces

4. CONCLusions

REFERences

These photos conservation problems raised some questions before and during interventions, overcome by research, discussion, and trial of methodologies and materials, respecting both compatibility and reversibility. In each case either lacunae infill contrast, between

[1] PAVÃO, Luis. – Conservação de Coleções de Fotografia. Lisboa: Dinalivro, 1997.

the original surface and the reintegrated area, and the chromatic reintegration were the most difficult and lengthy steps to execute. The size and shape of the lacunae, mainly the biggest ones, posed some questions relating lines continuity and hue gradient, due to non-existent references around those areas. Nonetheless this conservation work allowed the preservation, aesthetic and formal reading of these photographs, thus returning charm and respect for the people portrayed.

[2] MOSCIARO, Clara. – Diagnóstico de Conservação de Coleções Fotográficas. Rio de Janeiro: Funarte/ Centro de Conservação e Preservação Fotográfica (CCPF), Caderno Técnico nº 6, 2010. Available at: http://www.funarte.gov. br/preservacaofotografica/wp-content/uploads/2010/11/ cad6_port.pdf. [08 September 2015]. [3] FUENTES de CÍA, Ángel María; ARILLO, Jesús Robledano. Capítulo 3: La identificación y preservación de los materiales fotográficos. Manual de Documentación Fotográfica. Buenos Aires: EDENA, (not dated). Available at: http://www.edena.mindef.gob.ar/docs/Identificacion_ preservacion_Angel_Fuentes.pdf. [15 September 2015]. [4] REILLY, James. – Care and Identification of 19th Century Photographic Prints. Rochester: Eastman Kodak Company, 1986. [5] MESTRE I VERGES, Jordi. – Identificación y conservación de fotografías. Gijón: Ediciones Trea, D.L., 2011. [6] STULIK, Dusan C.; KAPLAN, Art. The Atlas of Analytical Signatures of Photographic Processes, Silver Gelatin. Los Angeles: The Getty Conservation Institute, 2013. Available at: http://www.getty.edu/conservation/publications_ resources/pdf_publications/pdf/atlas_silver_gelatin. pdf>. [18 September 2015]. [7] DUNE, Corinne; GRINDE, Lene; WIEGANDT, Ralph. – Characterization of Black-and-White Silver Gelatine Fiber-Based Photographic Prints. Presented at the 2005 Photographic Materials Group PMG Winter Meeting, Vancouver, B.C. Topics in Photographic Preservation, Volume Eleven, (2005), pp.1-19. Washington, D.C.: American Institute for Conservation of Historic and Artistic Works (AIC). Available at: http:// notesonphotographs.org/images/0/05/Characterization_ BW_GSP_prints_for_web.pdf. [18 September 2015]. [8] VALVERDE, Maria Fernanda. – Diagnostico del estado de conservacíon. In: FRACORNEL, Guilherme; TAMARGO, Consuelo; VALVERDE, Maria Fernanda. Manual de diagnóstico de conservacíon en archivos fotográficos. Ciudad Del Mexico: Archivo General de la Nacíon, 2000, p.13-41.

122


XIII

Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL


XIII.

Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

Liliana Cardeira (1), Fernando António Baptista Pereira(1), António Candeias (2), Sónia Costa(2), Luísa Carvalho(3), Marta Manso(1-3) (1) Faculty of Fine Arts, University of Lisbon (FBAUL) 1; Largo da Academia de Belas Artes 1249-058

Lisboa; E-mail address: lili_237@hotmail.com; fernandoabpereira@gmail.com

(2) HERCULES Lab and Chemistry Department, Evora University 2; Palácio do Vimioso, Largo Marquês de Marialva, 8 7000-809 Évora; E-mail address: candeias@uevora.pt; sonia_lopes_costa@hotmail.com

(3) LIBPys, New University of Lisbon 3; Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa 2829-516 Caparica; E-mail address: luisa.carvalho@fct.unl.pt; marta974@gmail.com

Abstract This study’s main goal is to present the process of chromatic reintegration of the painting “Batalha entre Gregos e Troianos” (Battle between Greeks and Trojans), an artwork belonging to the collection of paintings of the Faculty of Fine Arts, University of Lisbon (FBAUL)1 and created by the painter Adriano de Sousa Lopes (1879-1944) while a fine arts student in Lisbon (EBAL). Between 2014-2015, this artwork was submitted to analytical characterization in the laboratory, as well as conservation and restoration treatment. Retouching is one of the most visible aspects of conservation and restoration.. Envisioning the integrity of the painting above all, the choice of the chromatic reintegration was supported by the development of a good theoretical study and the ethical criteria of conservation and restoration used in the Faculty of Fine Arts. With this paper, we intend to elucidate the criteria that led us to choose the mimetic technique to retouch this Portuguese modern painting.

Keywords Adriano de Sousa Lopes, FBAUL, Retouching, Mimetic.

1

CARDEIRA, 2014, pp. 27-34.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

125


XIII. Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

1. Introduction This paper presents a study developed around the painting “Batalha entre Gregos e Troianos”2 from Adriano de Sousa Lopes, a Portuguese painter from the 20th century. The chosen artwork, belonging now to the collection of paintings at the Faculty of Fine Arts, University of Lisbon (FBAUL), was created by Sousa Lopes as while a Fine Arts student in Lisbon (EBAL). The conservation of this piece was based on knowledge of its production: techniques and materials used by the artist. The methodology selected for this conservation and restoration intervention, took into account the analysis made to the canvas support and to the chromatic layer. The painting was in poor condition due to various factors of environmental degradation and human negligence3. We decided that the dimension area of losses of chromatic reintegration would set the reintegration technique to apply.

1.1. Adriano Sousa Lopes and painting Batalha entre Gregos e Troianos

Adriano de Sousa Lopes (1879-1944), with a noticeable aptitude for drawing and painting had no difficulties in entering, as student, in the General Course of drawing4 at the School of Fine Arts of Lisbon (EBAL) and later in the 2

126

Historical Painting Course. He stood out with good marks in tests of frequency, receiving several medals and awards. In 1903, he competes and wins the scholarship given by Viscount Valmor on the history painting section, representing the seventeenth canto of Homer’s Iliad. He was the only competitor to the historical painting scholarship, on which he had to develop a piece based on Homero’s passage. He made a picture who deserved praise, showing early the safety in the drawing and some vivacity in the color. Inspired by the seventeenth canto of the Iliad, portrays the scene, Menelaus and Meriones striving to get rid of the rage of the Trojans Patrócolo corpse. The scene represents a violent struggle, where the shields and the warrior faces, glow, illuminated by the sun. Although there is no overall balance in the composition of elements, which is natural in a young painter, this episode breathes poetry, rudeness and heroism.5 The painting technique used in “Batalha entre Gregos e Troianos” is oil on canvas and its dimensions are: 96cm by 121 cm width. In order to understand the painter’s technique and the materials applied we resorted to methods of examination and analysis6 that allow us to understand the painting and its conservation status. Only after this was possible to establish an appropriate and diverse methodology for the intervention.

Cf. HOMERO. (1999) A Ilíada. Sintra: Europa América, XVII Canto.

3 CARDEIRA, 2014, pp. 27, 28.

5 SANTOS, 1962, p.15.

4 PEREZ, 2012, p. 17.

6 STUART, 2007, p. 72-76.


XIII. Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

of the different chromatic reintegration techniques. Our choice prevailed in keeping the uniformity of the collection by choosing a conservation method already used in the Faculty of Fine arts: the chromatic reintegration. The Faculty of Fine Arts is apologist of the mimetic reintegration, when applied in missing zones with enough information for the reconstruction. Figure 1. Batalha entre Gregos e Troianos, 98,8cm x 123,3cm. Ana Mafalda Cardeira photography with support Liliana Cardeira.

In this context, we carried out a survey of the painting conservation status (see Table 1) and developed an intervention methodology based on technical, physical and mechanical characteristics of the original painting, compatibility, removability and environmental conditions.

Table 1. Conservation State.

The painting, before it is conditioned in the Painting storage of FBAUL was saved in an office where suffered fire damages.

It was in the building that today holds FBAUL, which the first nineteenth century interventions were made by painters-restorers such as Luciano Freire7,8. Despite being the owner of the work who decides the type of intervention, we have to define our work process based on knowledge of previous interventions of conservation and restoration of the painting collection and ethical matters9. The chromatic layer loss is situated on the right part of the painting, where we can see several flesh tones. The extension and shape of the uneven loss was presented up to the support. After a lot of research we found a photograph of the painting before the fire accident. It was concluded that being a recent modernist work, the painting was not presenting much degradation and therefore we applied a high degree of reintegration, since all the losses were filled. As mentioned before, the chosen methodology was the retouching of the missing zones. For

2. Materials and methods 7 ALVES, 2011, pp. 36-42.

To define the best intervention method we also analyzed the advantages and disadvantages

8 ALVES, 2011, pp. 9-11. 9 FRANCISCO, 2011, pp. 44-71.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

127


XIII. Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

that, we followed the methodologies adapted to interventions of the pictorial collection in the years prior to this intervention and also the color information obtained from the painting.

normally, soluble in nonpolar solvents.

The intervention began with the application of techniques of the examination, like methods of exam and analysis, used in study of shape and impasto. As criteria, we decided to refill the missing zones of the painting, using different materials, which are more easily removable, and the mimetic retouching technique. The losses of Figure 2. Material used in reintegration. the pictorial layer were not large. The losses had the information about the shape and colors. In a second phase, we wanted a fine retouching, The intervention began with examination transparent and durable. Thus, we use the techniques like methods of exam and analysis, used in study of shape and impasto. We powdered pigments of Ferrario®, diluted in determined to refill the missing zones of the White spirit® and in retouching varnish of painting using different materials, which are Talents® more easily removable, and the mimetic retouching technique. The losses of the pictorial layer were not large and gave us information about the shape and colors. The choice of this type of reintegration technique intends to reduce evidences of deterioration.

2.1. Materials Used

We used a brush of Winsor & Newton® 7 series, which have the advantage of having uniform brushstrokes, optimum color carrying capacity, soft hair brushes to control flow and natural and synthetic hair to retain brush shape. As a third and last stage it was placed a varnish spray layer to touch up so as to bridge differences in brightness.

During the intervention we sought to use materials which are compatible and removable. It was necessary to test some filling masses to put a filling in the preparatory layer, using the equivalence of textures in certain areas. For these fillers we applied Modostuc®. Initially it was decided to use a layer of watercolor Winsor & Newton® by applying a retouching varnish layer of Talens® for protection and isolation of the color layer. The retouching varnish of Talens® is a ketone resin Figure 3. Reintegration zone.

128


XIII. Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

In missing zones with a bigger amplitude, we decided retouch with small dots in order to achieve some lights and shadows.

3.1. Examination and analysis methods

3. RESULTS AND DISCUSSION The chosen reintegration was successful, since the area that was reinstated looked invisible to the casual observer but it’s easily identified when submitted to an UV light.

Figure 5. UV light photography. Before the treatment and after the chromatic reintegration.

The exam methods, which include UV light, are an indispensable tool in the identification of previous interventions. Thus, with photography of the UV light we can easily distinguish reintegrated losses ensuring the location and extension of our intervention.

Figure 4. Before and after the chromatic reintegration.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

129


XIII. Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

4. CONCLusions

we are faced with the aesthetic question: Reinstate or not reintegrate? It was decided, to integrate in order to establish the expressive potential of the work. The aim of this intervention methodology was to reduce the signs of deterioration patents in the paint “Batalha entre Gregos e Troianos”. Once there were no large losses and no important area or detail were missing, either in shape or colour, we decided to follow Emily-Male’s11 approach. According with this french art historian, the technique of mimetic reintegration when performed only in the losses area, with removable and different materials from the original painting, can be an effective solution12.

Figure 6. Before and after the intervention.

Our decisions had the artworks wellbeing as goal and took into account the environment in which the work is inserted, the type of painting, the relevance of lacuna areas, the compatibility and the stability of the work, the owner, etc.10 In the first instance, our option was intervention of conservation and restoration because of the conditions that the work presented. Equally, the painting belongs to a university collection with a pedagogic side and in that way we selected the chromatic reintegration in order to maintain a good read of the painting. However,

11 EMILE-MÂLE, 1976, p. 100. 12 EMILE-MÂLE, 1976, p. 100.

10 BAILÃO, 2011, p. 46.

130


XIII. Adriano de sousa lopes, batalha entre gregos e troianos – the painting colleCTION OF FBAUL

REFERences Thesis:

[1] CARDEIRA, L. – Conservação e restauro das obras do pintor Adriano de Sousa Lopes da Colecção de Pintura da FBAUL. Lisboa FBAUL: Dissertação de Mestrado em Ciências da Conservação, Restauro e Produção de Arte Contemporânea, 2014, pp. 27-34.

Book:

[10] ÊMILE-MÂLE, G. - Restauration dês peintures de chevale. Office du Livre:Friburgo, 1976. Scientific article:

[11] BAILÃO, A. – As técnicas de reintegração Cromática na Pintura: revisão historiográfica. Ge-conservación nº 2, 2011, pp. 45-6

Book Chapter:

[2] HOMERO. A Iliada. Sintra: Europa América, XVII Canto, 1999, pp. 244-260.

Thesis:

[3] CARDEIRA, L. – Conservação e restauro das obras do pintor Adriano de Sousa Lopes da Colecção de Pintura da FBAUL. Lisboa FBAUL: Dissertação de Mestrado em Ciências da Conservação, Restauro e Produção de Arte Contemporânea, 2014, pp. 27, 28 [4] PEREZ, M. F. H. P. - Adriano de Sousa Lopes – Director do Museu Nacional de Arte Contemporânea entre a continuidade e a mudança. Lisboa: Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa. Dissertação de Mestrado em Museologia, 2012, p. 17. Book:

[5] SANTOS, Manuel Faria dos; SANTOS, Reynaldo dos. Sousa Lopes. Lisboa: Liga dos Combatentes/ Fundação Calouste Gulbenkian, 1962.

Book Chapter:

[6] STUART, Barbara. Analytical Techniques in Material Conservation. England: Wiley, 2007, pp. 72-76.

Catalog:

[7] ALVES, A. N. – As práticas de restauro nas Belas Artes. Catálogo de Exposições – O restauro regressa às Belas-Artes – Retratos da Reserva de Pintura. Lisboa: FBAUL e CIEBA, 2011, pp. 36-42. [8] ALVES, A. N. - O restauro regressa às Belas-Artes – Retratos da Reserva de Pintura. Lisboa: FBAUL e CIEBA, 2011, pp. 9-11. [9] FRANCISCO, Catálogo de Exposições – O restauro regressa às Belas-Artes – Retratos da Reserva de Pintura. Lisboa: FBAUL e CIEBA, 2011, pp. 44-71.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

131


132


XIV

Hyperspectral imaging applied to the study of paintings color


XIV.

Hyperspectral imaging applied to the study of paintings color

Luís Bravo Pereira (1) (1) CITAR- Centro de Investigação em Ciência e Tecnologia das Arte, Universidade Católica Portuguesa; Porto; E-mail: luis.bravo.pereira@gmail.com

Abstract The present work shows some results obtained on building, calibrating and testing an hyperspectral system using a commercial digital camera (a Nikon D300 DSLR) that showed to be possible, entirely on the visible spectrum, to capture hyperspectral images composedof 28 bands, between 420 nm and 690 nm, in steps of 10 nm (22 bands are directly captured with the system and 6 are interpolated), a number of bands superior to many other multispectral and hyperspectral imaging systems built with more complex and expensive hardware. Compared to a reference spectroradiometer (Photoresearch PR650) using a standard 24 color chart ColorChecker X-Rite, showed average values for RMSE (Root Mean Square Error) of 3,4% and 99,3% for GFC (GoodnessofFitCoefficient); the colorimetric precision of the system presented values for color differences equations of 6,0968 units for , 3,8228 units forand 3,6794 units for ; the tested metameric indices showed values of 1,1457, 1,2410, 0,8078 and 0,7777 for illuminant pairs “D65,A” and “D65,F2”, all quantified in terms of color differences equationsand , respectively. Observing and analyzing individual isolated bands in certain wavelengths of the visible spectrum, allowed us to detect alterations in paintings, areas with repainting, reintegration, under drawings and other type of information, traditionally only possible to obtain using invisible radiation imagery [1]. Using adequate software it was possible simulate the appearance of the paintings under different types of illuminants, preventing more time-consuming experiences or, in both situations, avoiding submitting the painting to unnecessary stress or more destructive radiations.

Keywords Multispectral; Hyperspectral; Metamerism; Colour accuracy.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

135


XIV. Hyperspectral imaging applied to the study of paintings color

1. Introduction The hyperspectral scanning of artworks has been intensively researched subject in the last decades, especially when applied to the study and documentation of paintings. The ability to have an accurate record of spectral reflectance distributions of a work surface opens a wide range of uses of great interest. The possibility of capturing images in more bands than the traditional three channels color models (the RGB model, commonly used on digital camera’s sensors), opens new possibilities, because this type of data contains reflectance values (data independent of the type of illuminant) and in an higher number of wavelength bands. This type of data is more color accurate than conventional photography and it is not susceptible to colors metamerism, a frequent problem with trichromatic reproduction systems [2]. The first step to access this possibility is the accurate recording of the spectral information covering a broad range of the electromagnetic spectrum - at least in the visible area of the spectrum. For the recording process, various systems have been developed in recent years by different authors, usually complex and timeconsuming prototypes, which reduces the practical applications to a limited audience. So there would be a great benefit if it would be possible to use equipment capable of performing this type of scanning, but based on the most common and usual components in the photographic studios of museums and art conservation centers, such as creating a scanning system built around common digital camera. However, it is much less frequent

136

to find publications mentioning the use of cameras with digital sensor and CFA (Color Filter Array) as spectral scanning devices applied to document, recording and analysis of works of art. As part of the research carried out with this work, for the first time it is incorporated in an hyperspectral scanning system, dedicated to works of Art, a D-SLR camera (sensor DX format, based on 35mm systems), a type of camera commonly used among the museums and researchers. The D-SLRs are actually the camera type most used by professional photographers today. For this reason it is of great interest a work like the present communication, when raising towards the validation or rejection of this type of cameras for use in multispectral or hyperspectral scanning systems. But when evaluating the results of the tested system, we cannot forget that it only reflects the capabilities of the system as a whole and not just the component represented by the camera’s sensor. That is, one should not conclude from the results that the type (or even model) of camera, by itself, is reflecting the quality of data and metrics applied to them because there will be other system components (besides the camera, we should consider the filters, light sources, calibration targets, methods used, etc.) that equally affect these results. For this reason, there is always room to develop the system in future works, since any improvement on the components or methodologies will consequently improve too the final performance of the hyperspectral system. The current version of a to explain in equipment,

communication is a resumed PhD thesis, so it is impossible the ambit of this article all the materials, methodology used


XIV. Hyperspectral imaging applied to the study of paintings color

to characterize the system, to capture the hyperspectral data, to implement the posterior data processing and metrics applied to validate de accuracy of the system, so we encourage the readers to consult the authors thesis [3] for more information (written in Portuguese language).

wheel remote control (R). A small web camera was also attached to the assembly, allowing easier way of checking correct positioning of the filters on the computer screen (W).

2. Materials and methods 2.1. System assembly

After testing four different camera models, we decided to build the system around a D-SLR camera, a Nikon D300, which acted as system’s image detector. Associated to the camera a dedicated motorized filter wheel with a set of 13 filters, 2 of them short band dichroic bandpass filtersand the other 11 filters being common photographic large band filters. The optical lens used with the camera was a “Coastal Optics UV-VIS-IR 60mm 1:4 Apo Macro”, a special type of lens that is apochromatic from 350 to 1100 nm. All these components were mounted in a frame that simultaneously hold together the camera, filter wheel and 4 light sources. The system was controlled by a computer and the data processed with software developed by the author using MatLab. The following figure shows the system operating in front of a painting, where we can see the four lamps, (indicated with F1, F2, F3 and F4), the camera (D-SLR), the filter wheel (RF), the computer (PC), the camera’s remote control (“C”, used only for “Bulb” longer exposures), and the motor’s filter

Figure 1. The hyperspectral system assembly, during operation.

2.2. Lighting

Two to four PAR16 12 volt projectors were used as light sources, containing Solux Lamps with the following specifications: 50 watt, angle of 35º, nominal correlated color temperature 4700 K. The lamps were displaced allowing an even distribution of light on the painting’s scanning surface. Camera, reference radiometer and light sources were assembled according to the CIE 45º/0º illuminant/observer geometry.

2.3. Reference system

To evaluate the spectral accuracy of the system, it was used the Photo research, Inc. PR650 Spectra Scan spectroradiometer. This system measures the electromagnetic spectrum from 380 to 780 nm, in 4 nm steps and with a viewing

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

137


XIV. Hyperspectral imaging applied to the study of paintings color

angle of 7º or 1º. Measuring the very same samples on the chosen targets (ColourCheker and artwork paintings), with the same number of steps and spectral range, we can apply in post-production some metrics to the recorded data allowing to determine the final accuracy of the system. This spectroradiometer was used also to characterize the spectral transmittance of the filters and to record the spectral distribution function of the light sources.

2.4. Other equipment used for characterization of the system

To characterize the camera’s sensor, we have used a TFT tunable interference liquid crystals filter: a VariSpec VIS-10, from Cambridge Research & Instrumentation, Inc.This equipment has a viewing angle of about 7º, in a spectral band from 400 to 700 nm, with steps from 1.5 to 10 nm. To characterize filters and to determine the spectral reflectance of recorded data, we used a reference white target Labsphere Spectralon ref. SRT-99-020; this special white reference target has a spectral reflectance factor over 99%, in all visible wavebands.

2.5. Methodology used for band selection

Combining the spectral transmittance distribution function of the 13 external filters with the camera sensor’s 3 internal filters (Red, Green and Blue, the Bayer Color Filter Array) we can select different bands using our software developed on MatLab.

138

2.6. Homogeneous and complex color target

For the first group of tests we have used a standard 24 colors “ColorChecker Color chart”, from XRite, inc. As a complex color target we used a XVI Century painting (“Triptico de Pentecostes”, from Miragaia, Porto) and a XX Century work of Art (“O Cabouqueiro”, by Julio Pomar).

3. RESULTS and Discussion The

spectral

data

recorded

with

this

hyperspectral system, even if not reaching the accuracy of more sophisticated equipment, showed that the proposed instrument is useful for a preliminary study, being also more versatile and simpler. The system register 28 spectral bands (in 10 nm steps, 22 bands are measured directly and 6 are interpolated), a number far superior to other existing systems [2,4,5], covering about 85% (420 to 690nm) of the electromagnetic spectrum bandwidthallowed by the reference system (400 to 720 nm in 33 bands of 10 to 10 nm); however, the handling and operation of all required system components and protocols, showed us that - at least at the prototype stage - the system was more complex and time consuming to operate than initially anticipated, yet simpler than equivalent systems. Finally, the metrics used to validate the spectral quality of the recorded data are encouraging towards the system validation, although there isn’t such a thing as a general consensus that establishes limits from which we can validate or not an hyperspectral system.


XIV. Hyperspectral imaging applied to the study of paintings color

In addition to the high spectral resolution, the system also allows for high spatial resolution, with more than 12 megapixels individual images: with the detector positioned at a distance around 1.8 meters from the painting surface, an image resolution of 6.2 pixels per millimeter was obtained, covering an area of 69X46 square centimeters. However, the versatility of this system, unlike other systems, allows to vary the spatial resolution as required: using the system closer to the painting surface, it is possible to proportionally increase the resolution or, if it is more important to cover a larger area, push it back and cover like this a bigger scanning area. The accuracy of the tested system can be supported by the obtained values for the spectral, colorimetric and metameric differences between spectral reflectance distributions estimated by the hyperspectral system and the ones measured by the reference spectroradiometer. With the homogeneous color samples (measured in a ColorChecker X-Rite, 24 colors target), in spectral terms the proposed system presented an average error of about 3.4%, quantified in terms of Root Mean Square Error (RMSE), and 99.3% quantified in terms of Goodness-of-fit Coefficient (GFC). With regard to the colorimetric quality, the tested hyperspectral system presented color differences of 6.0968 units in terms of , 3.8228 units ofand 3.6794 units of.

It can be further noted that the metrics of the achromatic samples are more accurate and complementary to the different luminosities measured and estimated along the achromatic scale, showing the linear photometric response of the proposed system. In regard of the artistic paintings, despite the higher color complexity of the compared samples, with one of the paintings (Triptico de Pentecostes de Miragaia, Porto) the hyperspectral system showed comparable results to those obtained with the homogeneous color samples target (some metrics were slightly higher, and others slightly lower); with the other painting (O Cabouqueiro, by Julio Pomar) it was difficult

to reduce or eliminate entirely the specular highlights (and that surely reduces the accuracy of the system), consequently the differences between the tested system and the reference system increased, for all the tested metrics. On the following image, we can see from left to right and from top to bottom, the images representing the painting under illuminants: CIE D50 (daylight), CIE D65 (daylight), CIE (tungsten lamp), Solux lamp, Xenon lamp, CIE F2 (fluorescent lamp); spectral bands with peak transmission at: 420 nm (blue) showingthe surface texture of the painting, 550 nm (green) and 690 nm (red) showing under drawings and areas missing the original pictorial layer.

As for metamerism indices, the system showed average values of 1.1457, 1.2410, 0.8078 and 0.7777 for illuminant pairs “D65,A” and “D65,F2”, quantified in terms of color differences equationsand, respectively.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

139


XIV. Hyperspectral imaging applied to the study of paintings color

the effect of any small errors in exposure, white balancing, among others, which affects the quality of the final color reproduction, free of metamerism influence.

Figure 2. Simulation of the detail work “TrĂ­ptico de Miragaiaâ€? before different illuminating and monochrome images in three spectral bands. Images by the author

4. CONCLusions With the appreciation of the results, it can be concluded that the system instudy, either in homogeneous color target, either in works of art (in which the sampled points present more chromatic complexity), allows the recording of spectral reflectance distributions with accuracy - at least good enough for many of the possible applications were we can use this type of images - and it is therefore suitable for hyperspectral scanning of works of art. As for practical applications usefulness in a real world context, besides the utility of comprehensive spectral information for future archival - far more complete spectral recording than the simple conventional photography, that uses the RGB trichromacy model - the system has recorded the data eliminating the influence of the light source (illuminant), as a consequence of storing information as a spectral distribution of reflectances while conventional photography keeps only radiances data. This allows also to eliminate 140

With the hyperspectral information recorded in both paintings, it was possible to demonstrate some interesting applications of this technology: we could simulate the final appearance of a specific painting when illuminated by different types of light sources. When analyzing isolated spectral band images it was also possible to identify retouches and reintegration areas, identify the surface texture of the painting, detect the under drawing; these techniques are usually only available with infrared or ultraviolet imaging, but here in this case it was possible to have it only in the visible range of the electromagnetic spectrum, with the advantage of avoiding to submit the work of art to more aggressive radiation (as is the case, for example, when using ultraviolet radiation). In short, we believe that the present work allowed us to validate the use of digital cameras - D-SLR type, which are intended for a general photographic use - for hyperspectral recording of works of art, with sufficient reliability for scientific use. The possibilities brought by this type of spectral technology are many and the fact that it is possible to develop practical applications with affordable equipment, can even allow the use of this type of equipment by a broader range of users.


XIV. Hyperspectral imaging applied to the study of paintings color

REFERences [1] PIRES, H., LIMA, P., & PEREIRA, L. B. (2009). Novos Métodos de registo digital de arte rupestre: digitalização tridimensional e fotografia multiespectral. Paper presented at the Jornadas Raianas, Sabugal. [2] FERREIRA, F. B. Digitalização Hiperespectral de Pinturas e Obras de Arte. PhD dissertation. Covilhã: Universidade da Beira Interior, 2010. [3] PEREIRA, L. B. Imagens Hiperespetrais Aplicadas ao Estudo e Conservação de Obras Pictóricas. PhD dissertation. Porto: Universidade Católica Portuguesa, 2014. [4] CORTÉS, A. R.. Analyse multispectrale et reconstruction de la réflectance spectrale de tableaux de maître. PhD Dissertation. Paris: École Nationale Supérieure des Télécommunications, 2003. [5] HARDEBERG, J.Y. Acquisition and reproduction of colour images: colorimetric and multispectral approaches. PhD Dissertation. Paris: École Nationale Supérieure des Télécommunications, 1999.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

141


142


XV

APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM


XV.

APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

Mary Kempski Hamilton Kerr Institute, University of Cambridge, Mill Lane, Whittlesford, Cambridge CB22 4NE, UK mek27@cam.ac.uk

Abstract This paper will focus on the various approaches to retouching taken by the Hamilton Kerr Institute, given different retouching problems presented by various types and periods of painting. It will also discuss a retouching method very little used these days, but one that has many advantages, including the fact it is an excellent imitator of aged oil paint. The usual methodology at the Institute is to cover losses with mimetic retouching. However certain situations will not suit such an approach and other solutions have been used. Case studies include the Thornham Parva Retable and the Westminster Retable, two medieval altarpieces, where different and inconsistent approaches were required on the single work of art. This is compared with an Italian painting by Sebastiano del Piombo, where the losses were so numerous and large that a mimetic reconstruction appeared to be impossible. However the decision was made to reconstruct the losses due to the fact that many types of complimentary information could be used to help build the image again. The use of egg tempera as a retouching medium, which originated in Germany, was brought to the UK in the early 20th century. The method has since been adapted to accommodate synthetic varnishes and has continued to be used at the Hamilton Kerr Institute. It is not initially an easy method to master, but a short description will illustrate its value as a retouching choice.

Keywords Retouching approaches; Egg tempera retouching.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

145


XV. APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

1. INTRODUCTION

2. CASE STUDIES

I will discuss some restoration issues we have experienced in the past at the Hamilton Kerr Institute [1] and the solutions we have adopted. Our approach to retouching is tailored depending on the date of the work of art and the perceived expectation in restoring each particular area of loss.

There are many approaches to restoration. Historically, these have often varied with changing taste.Today science and technology has also influenced methodology. However, there are also many approaches within one historical period based on geography and

The Institute has tended to follow in the tradition of retouching that came originally from Germany in the 19th century. It was brought by émigré restorers to England in the early 20th century and was continued at the National Gallery, London, by Helmut Ruhemann [2]. He used an egg tempera medium for his retouchings. These were, on the whole, mimetic and brought to a fairly high degree of finish. A quote from David Bomford about restoration approaches, from a paper given at the British Museum in 1994, remains pertinent today: “To confront a cleaned but unrestored painting is to confront one of the standard dilemmas of paintings conservation. On the one hand, the art historian needs to know how much of a painting is original and, on the other hand, the viewer of a work of art wishes to see an image uninterrupted by loss and damage. The first might be termed the historical or academic requirement, the second the aesthetic requirement. The restoration of painting in the sense of retouching is nowadays concerned with finding a compromise between these two requirements” [3].

146

school. Conservators today will be aware of an ethical code of practice and are also aware of possible different approaches. In the 20th century, influenced particularly by Cesare Brandi, there was a feeling that retouchings should be distinguishable [4]. This creates an enormous responsibility for the conservator who, as in the earlier quote of Bomford, is always trying to find a compromise. Perhaps now in the 21st century we can call on other forms of communication to resolve this problem. We have so many more techniques for providing information and instructing the viewer what is original on a painting, without having to make it always immediately obvious on the work of art itself.

2.1. Medieval Case Studies

I start my case studies with two rare medieval English altar pieces that were restored at the Hamilton Kerr Institute [5]. In England most medieval ecclesiastical artworks were destroyed in the Reformation in the 16th century or during the Protectorate of Oliver Cromwell in the 17th century, so these early works presented us with new questions and decisions concerning their restoration. The restoration of these medieval works of art were problematic and there was a concern that, if we completed all areas of restoration to a similar


XV. APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

level, the result would not be in keeping with the expected condition of a medieval object, in other words they would not be believable [6]. The condition of the Thornham Parva Retable is remarkably good, much of the figurative paint remains. However, the background, which is made up of small squares of decorative tin relief, has lost nearly all its original gilding. We wanted to do the least amount of retouching to the figures that would seem acceptable. On the figure of Christ our approach is illustrated here. The body is quite badly damaged showing the strong grain of the oak panel. Here one could describe this area of the painting, visually, as damages with an image, rather than an image with damages [7]. Our solution was to tone down the interfering rays in the wood grain with glazing, slightly lightening the area so that it was not too dissimilar tonally from the flesh paint (Figure 1). With the figure of St Catherine, the drapery revealed paint loss after removal of the 18th century repaint. Similarly, this was restored by toning the rays on the wood. Now the damages seem to recede behind the original paint. The iconoclastic scratches in the heads were not retouched as they were of great historical interest.

Figure 1. Thornham Parva Retable, detail of Christ after restoration

With the gilded background another approach was attempted. The tin relief back ground was made up originally of red pigments with oil, mixed into a paste, which was pressed into the various moulds of tin foil. These were attached to the panel and the surface was then gilded. Unfortunately the tin corroded with time and the gold leaf did not survive. It was felt that the large areas of the dark red colour of the relief had a deleterious effect on the appreciation of the altarpiece, especially if one imagines how the gilding would have looked originally, in the flickering candlelight of a church. The large areas of gilding were paramount to the appreciation of the composition. We felt in the case of the gilded background it was certainly ethical to reinstate it, but with some wear and aging. The amount of wear could only be judged in an empirical way. We discovered the best way to achieve this, was to gild the whole background, covering all the areas which were originally gilded and then abrade the leaf gradually, stopping at each stage to assess the overall image, since original

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

147


XV. APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

gilding on the spandrels also had to balance (Figure 2). It was quite an experience to see the Retable as it might have looked originally, with its complete un-aged gilding - a little too overpowering for our tastes today.

Figure 2. Thornham Parva Retable, detail of St John the Baptist before re-gilding and after re-gilding with the abrasion completed.

Although the approaches to restoration on this Retable were not especially consistent we felt the different materials required these diverse approaches. The Westminster Retable, dated to 1267 is even earlier than the Thornham Parva Retable, but the paint that remains is of such high quality that the original paint was simply left to make its impact, although fragmentary in places. The right third of the Retable had been scraped down to the panel in the 18th century. Some tidying up of the visible wood panel was required in all areas and small areas of white ground were toned, but little more restoration was necessary [8].

148

2.2. Renaissance Case Study

For these two medieval paintings our approach was adapted to fit the situation. The next example is a Renaissance painting with a unique conservation history. The painting, The Adoration of the Shepherds, by Sebastiano del Piombo is set in an outdoor landscape, with a great feeling of distance, particularly after a flattening discoloured varnish and much repaint had been removed. Here it is possible to appreciate the different approaches to restoration between the medieval and renaissance painting. The medieval painting depicts a limited space within the picture plane, the background is often flat and gilded. The viewer can accept damages that reveal the wood panel, because we are not being asked to suspend reality and imagine a distant landscape within the confines of an indoor room. If we leave a realistic painting of a landscape un-restored, or with some form of engineered retouching, the integrity of the invention is lost. This would be the case with this painting by Sebastiano del Piombo. The painting is thought to have been made by Sebastiano just as he came to Rome in 1510 or 11. It still has all the colour of Venice but now Sebastiano is seeing the work of Michelangelo and Raphael. The painting belongs to the Fitzwilliam Museum and was bought by the founder of the Museum from France in 1800. It was recorded in the collection of the Duc d’Orleans in 1727. Here in France the painting was subjected to an extraordinarily invasive treatment in the 18th century. It was transferred from a panel to a canvas support.The painting was most likely placed in an acid bath and the panel removed from the back of the painting


XV. APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

by dissolving the gesso ground. The painting is now lined onto to 2 canvasses and it would seem that it suffered an enormous amount of paint loss during this excessive procedure. These enormous losses were repainted in successive campaigns of cleaning and retouching so that by the 20th century most of the picture was overpainted. After many years of deferring a decision one was made to remove all the repaint. It was felt that the original paint by Sebastiano that was left, a major artist with few works to his name, warranted revealing (Figure 3).

Figure 3. Sebastiano del Piombo, Adoration of the Shepherds, after cleaning and filling.

2.3. Technical Assistance

Once the full extent of the losses was known, a decision on how the painting should be restored was paramount. A committee was formed and it was decided that the nature of the painting required that the restoration be to a quite high imitative level. Given the size of these losses, this might have seemed like folly. However, there were several events which allowed this restoration to become reality. The first was a copy of the painting, belonging to the Louvre, made by an unknown artist, while the painting was still in France.

The copy was lent to the Institute. Secondly, many technical aids were used that proved extremely helpful in piecing together evidence for the reconstruction of the large areas of loss. Unfortunately the copy had been greatly overpainted, particularly in the Virgin’s blue drapery, which was one of the reference areas essential to the restoration: it was one of the largest areas of loss on the original painting. Fortunately we were able to use the University of Antwerp’s Macro-x-ray fluorescence capability to have the copy undergo analysis [9]. The results, with very careful interpretation, were extremely helpful in allowing us to be confident of the composition beneath the present overpainting. The Virgin’s robe in the copy was known to have been made in smalt so the scan indicating the element cobalt was particularly helpful in depicting the lie of the folds (Figure 4). The small losses presented no problem and could be retouched using the evidence of the original paint. For the larger losses much information was gained from other paintings by Sebastiano, for example, basing the shepherds’ faces of on face types from the Raising of Lazarus from the National Gallery, London. The retouching could be left slightly unresolved in some areas in keeping with some of the more abraded parts of the original painting (Figure 5). Present discussion is how the painting should be displayed and what information should be presented with it, or how the evidence of its condition should be made available to the public. These days many museums are becoming more technology-aware and multimedia devices giving detailed information, to those who desire it, might be a way of informing the viewer of the restoration.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

149


XV. APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

layers of egg tempera will also work.

3.1. Advantages

Egg used for retouching is a mix of the egg yolk and egg white. The diluent for this egg medium is water, so this is ideal health wise. Figure 4. Detail of the Virgin’s robe from the copy, in normal light and in a MA-XRF scan, showing the element cobalt.

Figure 5. Sebastiano del Piombo, Adoration of the Shepherds, after restoration.

3. EGG TEMPERA RETOUCHING Today we have a lot of choice when it comes to reliable synthetic retouching materials [10]. However, I would argue, none of the synthetic resins have quite the same pleasing handling qualities as egg tempera. Very quickly a resin retouching can become thick and sticky. Most conservators, when using a synthetic resin medium, rely on a combination of the layers producing an impression of the final colour, rather than the actual visual effect of one layer on top of another, which is how layers of aged oil paint in a painting will behave and how the 150

It is a clean and precise medium. A retouching is built up in thin layers which imitate exactly those on the painting. Some study of the paint layers is required before retouching begins but this should not be extra work for a conservator who has already cleaned the painting. The retouching can be taken almost to completion with egg tempera, as it is more versatile than gouache or watercolour and can be made opaque or transparent depending on which pigments are used. It can then be glazed with a varnish medium of choice. It imitates aged oil paint well and can be manipulated so that layers can be abraded or textured. Chalk can be mixed in with the paint to give it bulk, for example, producing an impression of brush strokes. Mowiol 4-88 mixed with chalk is another way of achieving texture on top of the fill. Paraloid B72 gels may also be used on top of the retouching. Egg tempera does not change with aging so combined with a small amount of synthetic varnish it would seem to have the credentials for one of the most stable of retouching media. Tempera can be used in combination with any synthetic resin. Gamblin colours can be used to glaze on top of a tempera retouching and Laropal A81 or Paraloid B72 can be used as a varnish between the layers of tempera, allowing the conservator to dictate the gloss or mattness of a retouching. A spray varnish can


XV. APPROACHES TO RESTORATION AT THE HAMILTON KERR INSTITUTE AND THE USE OF EGG TEMPERA AS A RETOUCHING MEDIUM

be used on top with any of these varnishes. So little medium is required for each layer of tempera paint, that its solubility is not an issue. Added to this, varnish between the layers will also remain as a release layer. However, a synthetic resin medium is advisable for areas of abrasion on a painting. Not every painting may be a suitable candidate for egg tempera retouching.

4. CONCLUSIONS The use of egg tempera has allowed for the production of top class mimetic retouching at the Hamilton Kerr Institute. Correct texture, colour matching and an understanding of the artist’s technique contribute to the stable and aesthetically superior retouchings egg tempera is capable of. I have shown that early medieval paintings may require a different approach to a general mimetic one. Here the Institute has employed various approaches on the one work of art. From the Renaissance onwards a mimetic approach is the most appealing, given that the viewer is somehow informed of the actual condition of the painting, which, in the case of the painting by Sebastiano del Piombo, is requisite after the painting has been aesthetically appreciated as a great work by a master.

REFERENCES [1] The Hamilton Kerr Institute is a department of the Fitzwilliam Museum and a teaching institute of the University of Cambridge. [2] RUHEMANN, Helmut – The Cleaning of Paintings: Problems and Potentialities. London: Faber and Faber, 1968. [3] BOMFORD, David – The Changing Taste in the Restoration of Paintings. Restoration: is it Acceptable? In ODDY, Andrew, ed – Occasional Paper 99, British Museum, Department of Conservation 1994, pp. 33-41. [4] MUIR, Kim – Approaches to the reintegration of paint loss: theory and practice in the conservation of easel paintings. ICOM Reviews in Conservation. n.º 10 (2009), pp. 19-29. [5] MASSING, Ann ed. – The Thornham Parva Retable. The Hamilton Kerr Institute, University of Cambridge: Harvey Miller Publishers, 2003. [6] McCLURE, Ian – A Developing Approach to the Restoration of Medieval Panel Paintings. In The Postprints of the Re-integration Conference. Northumbria: Northumbria University Press, 2007, pp.113-119. [7] WIIK, Svein – Perception Psychology in Re-Integration Processes. In The Postprints of the Re-integration Conference. Northumbria: Northumbria University Press, 2007, p. 98. [8] BINSKI, Paul; MASSING, Ann, ed. – The Westminster Retable, History, Technique, Conservation. The Hamilton Kerr Institute, Harvey Miller Publishers, 2009. [9] ALFED, Matthias; VAZ PEDROSO, Joana; VAN EIKEMA HOMMES, Margriet; VAN DER SNICKT, Geert; TAUBER, Gwen; BLASS, Jorik; HASCHE, Michael; ERLER, Klaus; DIK, Joris and JANSSENS Koen - A mobile instrument for insitu scanning macro-XRF investigation of historical paintings. Journal of Analytical Atomic Spectrometry. n.º 28, (2013) pp. 760-767. [10] ELLISON, Rebecca; SMITHEN, Patricia; TURNBALL, Rachel, ed. – Mixing and Matching. Approaches to Retouching Paintings. London: Archetype, 2010.

Acknowledgements Photographs taken by Chris Titmus, Hamilton Kerr Institute. Youjin Noh, restoration of the Sebastiano del Piombo painting (publication forthcoming). Stijn Legrand, MA-XRF scanning, Antwerp University.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

151


152


XVI

AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS


XVI.

AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS Mohamed Abdeldayem Ahmed Soltan, PhD

Northumbria University; Postal address: Building 13, Floor 3, Flat 33, Tawnyat Somouha, Alexandria, Egypt; E-mail address: dayem80@gmail.com

Abstract The research considers whether traditional image reintegration treatments are appropriate for the airbrush easel paintings and evaluate alternative approaches. A survey was conducted to discover how well conservators understood the degradation characteristics of easel paintings executed with airbrushing techniques, and their appropriate treatment. It revealed that there was a high level of uncertainty amongst practitioners in the field of paintings conservation with regard to the deterioration characteristics of air brush painting or their appropriate resolution. However, the major concern with regard to conservation lay clearly within the field of image re-integration as a result of its characteristically smooth surface finish. A range of approaches to image re-integration were ultimately trialled ranging from the traditional paint-based approaches to the use of digital coloured light. The latter was of particular interest in offering a truly reversible none interventive approach to re-integration. The focus of the digital re-integration techniques was to evaluate the viability of its use in general practice. The use of digital approaches using coloured light was more successful although further research is required in order to develop this approach for wide spread professional practice.

Keywords Image reintegration; Airbrush; Easel Paintings; Non-Interventive Conservation.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

155


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

1. INTRODUCTION In the late 19 Century, a man called Frank L. Smith, a photo-retoucher from Wisconsin, said: “there is perhaps no tool, that has ever been invented for the help of the artist, that has received so much abuse as the Air Brush” [1] A vague notion of ‘debasing art’ because of a ‘mechanical’ instrument was possibly shared by many fine artists since the airbrush was first marketed in the late 19th Century and through the early years of the 20th Century, as Man Ray points out: “When I began painting with the airbrush I had already been accused of debasing art by painting with a mechanical instrument.” [2] Interestingly, the word ‘mechanical’ was used as accusation against the airbrush, almost from the time the airbrush was first introduced to the market in 1883. th

Similarly, airbrush easel paintings seem to have been overlooked by researchers in the field of conservation of fine art. Curiously, there is no source so far known to have investigated the impact of airbrushing techniques upon the condition of paintings. The established conservation scientist Tom Learner argues that: “artists throughout the Twentieth Century experimented with all means of applying the paint to the substrate, such as paint rollers, spray guns, splashing and pouring – and this is another factor that can significantly affect the characteristics of the final paint film and its subsequent reaction to ageing and treatment.” [3] Since airbrushing is one of the “means of applying the paint to the substrate,” given its influence on the paint film thickness and distribution, could be as significant as the materials in terms of the art conservation research.

156

1.1. The Airbrush and Twentieth Century Fine Art

The airbrush remained, into the early years of the Twentieth Century, to have been used essentially for illustration, graphic design and photographic retouching. In fact, it even “played a crucial role in the development of” those types of art and helped shape the popular art of the Twentieth Century [5]. In those early years the airbrush was gradually employed in fine art. The British illustrator Michael English (1941-2009) asserts that the airbrush started to have direct and indirect influence on fine art. The use of the airbrush in fine art painting started as experimental. It was just used marginally to help achieve certain, and limited, effects in paintings. Several fine artists declined traditional techniques and became more and more inclined to search for and experiment with new tools and unconventional techniques to help shape their new ideas. Among early artists who employed airbrushing techniques are Man Ray, Kandinsky, Paul Klee and Siqueiros. By the mid-Twentieth Century, the airbrush became perfectly situated along with the other tools of even more artists. More than a few artists from different Post-WWII artistic movements actively used the airbrushes and spray guns. Examples of Color-Field artists are; Jules Olitski and Dan Christensen, Pop Art; James Rosenquist and Peter Philips, Photorealism; Chuck Close and Don Eddy. It is also important to note that the 20th Century came with an introduction of a vast array of synthetic polymers, from which several compounds have been manufactured into paints and coatings. Many artists have been eager to venture new boundaries with the help


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

of those new materials. With little doubt, it could be said that airbrushing would not have been seriously employed in fine art painting without the introduction of synthetic paints. Acrylic emulsion paints, in particular, were even more advantageous for airbrush artists. The Photorealist Chuck Close is an eminent example as an artist who relied on the airbrush and acrylic paints to execute a series of large canvas paintings between the 1960s and the 1970s. Close, in a recorded interview [6], described his technique: “When I got the white canvas I put fifteen coats of sanded of gesso.” Subsequently, three acrylic paints were diluted to be applied to his paintings via airbrushing. Those paints constituted the primary colours; red, blue and yellow. The paints were applied sequentially and directly on canvas with the airbrush to simulate the CMY printing process.

Accordingly, the main research hypothesis can be summarised in two points, as follows: • Airbrush easel paintings are more problematic when comes to image reintegration. • There could be effective, feasible and yet reversible image reintegration methods for airbrush easel paintings. This study aims to achieve objective answers to the research hypothesis. It aims to evaluate any issues that could be characteristic to airbrushed paint films. It also aims to evaluate the applicability of conventional image reintegration treatments for airbrush easel paintings, and to investigate other possible image reintegration treatments.

2. MATERIALS AND METHODS 1.2. Research Aims

This research focuses on airbrushing from a new perspective with regard to its role in the modern history of fine art and the consequences of its use on the stability of the paint film and potential conservation treatment. The flat topography of the surface of a typical airbrush painting, which consists of millions of seamlessly contiguous and successive dots of sprayed paints and lacks of brushstrokes, is the most distinct factor which causes further difficulties when comes to image reintegration treatment. With such an appearance even the tiniest defect would be obvious to the eyes of the viewers.

An interdisciplinary methodology is followed for this research, as summarised in the following points: • Survey of the characteristics and conservation of airbrush easel paintings undertaken in the form of a questionnaire distributed globally among art conservators. • Ultimately, different interventive and non-interventive image reintegration treatments that were trialled using a mock-up airbrush painting. This was in order to search for a safer and more effective solution.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

157


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

2.1. Survey

The preliminary aim of this study was to achieve an understanding of the main issues encountered in airbrush easel paintings within the field of art conservation. Therefore, a survey was conducted in the form of a questionnaire intended for conservators specialised in easel paintings. The goals of this questionnaire can be summarised in the following points:

to guide respondents through to their relevant questions according to preliminary responses (Figure 1).

• To assess the extent of current knowledge amongst art conservators in terms of conservation problems presented by airbrush easel paintings. • To evaluate the scale of the problem of airbrush easel paintings requiring treatment compared to that of paintings of other techniques • To determine the level of practical experience that art conservators might have with airbrush easel paintings. • To identify main conservation problems that might be significantly related to the use of airbrushing techniques. • To achieve an understanding of the current conservation treatment methods commonly carried out by art conservators for problematic issues related directly to the technique of airbrushing. The questionnaire was built online using a dedicated web survey platform. By April 2013 the questionnaire was sent electronically via unique links to the email addresses of 1193 prospective participants, of which 62 respondents participated from 16 countries. The questionnaire was principally designed to have “routing instructions” via filter questions 158

Figure 1. A diagram of the design and sequence of the survey aimed at easel painting conservators as a part of the research in the form of a questionnaire.

The following points summarises the most important outcomes of this survey: • About 97% of the respondents agree that the painting can also be affected by the paint application technique used by the artist. • Only about 35% of the respondents agree that art conservators are knowledgeable about problems that might be directly related to airbrush easel paintings. This is particularly interesting, taking into account that


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

88.71% of the respondents asserted that they have at least eight years of experience as practitioners. • Among those who asserted that they have had direct experience with airbrush easel paintings, about 78% agreed that airbrush easel paintings can particularly show unusual problems (Figure 2). • About 67% of the latter respondents said that airbrush easel paintings often require image reintegration (Figure 3). The previous points indicate two important conclusions: First is the lack of established knowledge about airbrush easel paintings from the perspective of art conservation. Second is the need to look more deeply into the problems particularly related to the nature of sprayed paint films in those paintings and the type of subsequent image reintegration treatments they could require.

Figure 2. Graph illustrating ratio proportions of respondents according to their opinion whether conservation problems in airbrush easel paintings are different from those in paintings executed with other paint application types.

Figure 3. Graph illustrating ratio proportions of respondents according to their experience with the conservation treatments and procedures that airbrush easel paintings often require.

2.2. A non-interventive image reintegration treatment for airbrush easel paintings

A smaller scale mock-up painting was executed after a detail of Chuck Close’s John (Figure 4). Close’s technique was followed using the three primary acrylic colours; cyan, magenta and yellow applied sequentially and directly on the canvas using airbrushing on a smooth acrylic gesso ground.

Figure 4. Mock-up painting of a detail from John (after Chuck Close). The surface appears highly even despite being photographed under raking light.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

159


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

Afterwards, losses were deliberately created in the form of scraping, using sandpaper with a high grade of coarseness.

Figure 5. This area of the mock-up painting was deliberately damaged by scraping it using sandpaper.

Traditional interventive image reintegration treatment was trialled with totally unsatisfactory results. The paint was applied by dotting to try to mimic, as far as possible, the very fine spots sprayed with the airbrush. It was, however, extremely difficult to achieve, and accordingly, highly time consuming, as dotting made by hand could not achieve the tiny size of the sprayed spots (Figure 6).

projector was used for this purpose. Its weight is 430g (14 cm x 11.6 cm x 4.1 cm), which is capable to produce up to 300 ANSI lumens and 10,000:1 contrast ratio. The native resolution of this projector is 1280 x 800 (WXGA) and can recognise a maximum resolution of 1920 x 1080. It costed £300 at the time of purchase. A digital image of the mock-up painting prior to the deliberate damage was used to be projected for virtual loss compensation. Adobe® Photoshop® CC was the editing software used to subtract the contour of the area of loss with only the places where losses occurred including the tiniest hairline-like places of loss (Figure 7).

Figure 7. (left) the right part of the mock-painting where the area of loss is present, (right) the compensating digital image that was cut out, using photo-editing software, from a high-resolution reference digital image of the mock-up painting prior to the deliberate damage.

Figure 6. A close-up image shows greater detail of the airbrushed surface of the mock-up painting. The left side of the image shows the detailed network of ultra-fine paint dots applied by the airbrush. The right side of the image shows detail of the loss of the original paint layer that was deliberately made for testing.

The next step was to test virtual image reintegration on the mock-up painting. A portable Pico LED DLP projector Acer K130

160

The projected image provided promising visual results. There was a much safer, easier and better outcome than any of the interventive image reintegration methods known. It was found that the projected image works fine with the normal ambient light. The light level was found to have been within the recommended maximum level for museums with regard to moderately-sensitive objects (150 lux according to ICCROM [8]).


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

airbrushing can be problematic in terms of conservation treatment. Compensating for losses in airbrush easel paintings was deemed one of the most problematic issues by a representative number of art conservation practitioners.

Figure 8. The mock-up painting with damage present at its bottom right corner (above), the compensating image was digitally placed to represent its appearance by the DLP LED Pico projector (bottom).

There have been a few experimental applications of virtual image reintegration for artworks in general, even fewer for easel paintings in particular, which have been published. Those treatments mainly depended on light projectors to virtually compensate for losses on the surface of a painting, or any object in general. The virtual image reintegration of Mark Rothko’s Harvard Murals, is an important example in this context [8]. However, there have been limitations, such as the cost and weight of the projector. A DLP LED Pico projector, tested in this study, proved highly efficient for this purpose due to numerous advantages, including; portability, zero running costs, and safety for the painting.

3. RESULTS AND DISCUSSION The outcome of the survey questionnaire supports the preliminary hypothesis that easel paintings executed solely or mainly using

Conventional interventive image reintegration treatments do not serve well in terms of tackling problems that could occur on the paint layer of airbrush easel paintings. The non-interventive image reintegration using a DLP LED Pico projector has shown better capabilities in this context. That is due to more than one factor, more importantly low immediate cost, near-tozero running costs and the exceptional portability and small size of the DLP LED Pico projectors. Moreover, the LED lamp in this type of projector is relatively safer compared to the other types.

4. CONCLUSIONS The findings of this research offered answers to its main questions. Those answers are backed up with the outcomes and results of the approaches demonstrated and discussed in the present paper; the survey and the investigation of different image reintegration methods. The outcomes of the questionnaire aimed at painting conservators provided sensible information that shows a degree of uncertainty among practitioners with regard to the treatment of airbrush easel paintings, particularly with regard to image reintegration. This outcome contributes to the current body of knowledge in the field of art conservation by shedding light on an artistic technique which,

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

161


XVI. AN INVESTIGATION INTO THE IMAGE REINTEGRATION OF AIRBRUSH EASEL PAINTINGS

in itself, could pose concerns about those paintings executed with. The interventive image reintegration techniques investigated proved impractical, problematic and/or pose concerns with regard to integrity, reversibility and longevity. The application of light projection as noninterventive image reintegration technique offers more than one advantage for airbrush easel paintings. The current body of knowledge on the conservation of paintings shows so few attempts in using light projection for the purpose of image reintegration of paintings in general. Furthermore, there have been no such attempts done previously with airbrush easel paintings. Therefore, this study adds an image reintegration solution, viable in many ways, for this particular type of painting.

Acknowledgments This paper constitutes part of the outcomes of a PhD research programme undertaken by the author in Northumbria University, UK from 2008 to 2015, and funded by South Valley University, Egypt. The doctoral thesis is entitled: An Investigation into the History of the Airbrush and the Impact of the Conservation Treatment of Airbrushed Canvas Paintings. I would like to express my gratitude to my supervisors Miss Jean Brown and Dr Brian Singer for their guidance and support throughout this research programme. Many thanks also go to the sponsor.

162

REFERENCES [1] Penaluna, A. (2003) A critical investigation into the

[2]

[3]

[4] [5]

[6]

[7]

[8]

origins and development of the airbrush - 1878-1906. Unpublished Doctoral Thesis. Swansea Institute, University of Wales. Naumann, F. M. (2003) Conversion to Modernism: the early work of Man Ray. Piscataway, N.J London: Rutgers University Press. Learner, T. (2007) Modern paints uncovered: proceedings from the modern paints uncovered symposium. Los Angeles: Getty Conservation Institute. Ellsworth, S. (1903) ‘Liberty Walkup’, Rockford today: historical, descriptive, biographical, p. 139. Martin, J. (1983) The complete guide to airbrushing: techniques and materials. London: Thames and Hudson. Diamonstein-Spielvogel, B. (1979) ‘Inside New York’s Art World: Chuck Close’. Available at: http://www. youtube.com/watch?v=enF9ldgjFow [7 November 2014]. Alcántara, R. (2002) ‘Standards in Preventive Conservation: Meanings and Applications’. Available at: http://www.iccrom.org/ifrcdn/pdf/ICCROM_04_ StandardsPreventiveConser_en.pdf. [24 September 2014] Cuellar, S., Stenger, J., Gschwind, R., Mukaigawa, Y., Raskar, R., Eremin, K. and Khandekar, N. (2011) ‘Non-Invasive Color Restoration of Faded Paintings Using Light from a Digital Projector’, in. ICOM-CC 16th Triennial conference, pp. 1–9. Available at: http:// scholar.princeton.edu/scuellar/pages/projects [7 November 2014].


XVII

Further Developments on the use of BEVAÂŽ Gesso-P infills and Solutions for Reintegration of a large loss


XVII.

Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

Raquel Marques (1), Leslie Carlyle (1) (1) Departamento de Conservação e Restauro, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, Caparica, 2829-516, Portugal; E-mail address: raquel.marques.rm@gmail.com; leslie.carlyle@btinternet.com

Abstract Our previous presentation, in RECH2 [1], covered the use of BEVA® Gesso-P (BGP) for a large textured infill to replace a missing strip along the bottom of a 19th century portrait in oil.While it proved the ideal material for this purpose, BGP has significant drawbacks in use, to overcome which has required further explorations.Continued work with it to fill gaps between the replacement strip and the original paint, and to achieve very thin textured infills for irregular shallow losses elsewhere on the painting have required innovations to expand the versatility of this material. In addition, BGP’s textured surface is easily disrupted by solvents introduced during inpainting, such as those used in Gamblin Conservation Colors (e.g Shellsol A). As a consequence, various options for isolating layers were tested, with the result that Paraloid B-72 in acetone was chosen as it forms an effective barrier. Given the size of the loss (9 by 66 cm) and lack of information regarding what was present in the original image, a series of steps were followed to prepare for the reintegration. Drawings, computer imaging and trial paintings were used to arrive at the final design prior to its execution on the textured replacement strip. This paper will discuss the problems encountered and solutions found to exploit the working properties of BEVA® Gesso-P and the step by step procedure used to develop the appearance of the reintegration of such a large loss.

Keywords BEVA® Gesso-P; Infill; Texture; Paraloid B72; Reintegration; Gamblin Conservation Colors.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

165


XVII. Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

1. Introduction The painting which originated this work is a nineteenth century portrait in oil of Isabel Maria Lourenço Affonso (belonging to the Ecomuseu Municipal do Seixal). As detailed in our previous publication in RECH2 [1], the main problem was a large missing strip of both paint and canvas (approx. 9 by 66 cm) along the bottom edge of the painting. A textured replacement strip was crafted with BEVA® Gesso-P (BGP) since this material could be cast over a silicone mould of the painting’s surface texture in a thin, even and flexible film.

1.1. Working with BEVA® Gesso-P

The successful replacement strip was created in two steps (Fig.1 a & b): the first was to cast the painting texture using a silicone mould. A barrier film to protect the painting from silicone oils in the moulding material was made to confirm closely to the painting’s surface with the use of a vacuum cold table. In the second step, into the uniform thickness mould created, diluted BGP was spread in a thin even film. The BGP film created formed a flexible textured strip the same thickness of the combined paint and ground layer. It was incorporated with the painting during Mist Lining1 where it was adhered directly to the lining canvas.

Figure 1. a & b: a) Silicone mould with painting texture. b) Casting of BGP film from the silicone mould.

Since such a rewarding result was achieved with BGP and given that there were still further infills to complete on the painting, the aim of the work described here was explore the application of BGP as an infill material in a more traditional sense. For the different types of losses which remained, different approaches for the application method were pursued and will be described: hand-building the texture, casting a small textured fill, and imprinting the texture in-situ.

1.2. Determining what belongs on the missing strip

1

166

The Mist Lining technique with acrylic dispersions, evolved from Mehra ‘cold-lining’ technique [2] and was developed by the Head of Paintings Conservation at the SRAL institute, Jos van Och [3].

The other topic covered by this article is the investigation of the missing portion of the painting. Unfortunately no previous images of the painting exist, therefore it was necessary to determine what could be plausible as


XVII. Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

this forms the basis for decisions concerning the reintegration. The most obvious missing elements are the fingers of the sitter’s right hand and her drapery. In a meeting with specialists from the Museu Nacional dos Trajes (National Museum of Costume and Fashion)2 while discussing the dress style and elements that would have continued into the now missing strip,it was suggested that the sitter could be holding a fan as this was not unusualin 19th century female portraits which feature contemporary fashion. In fact, during varnish removal in an area badly blanched by water damage, two small areas of paint were revealed, one of which appears to indicate the presence of a fan, and the other, a ring, associated with one of the missing fingers (Fig. 2 a & b). These small indicators have contributed significantly to the proposed reintegration of the lost part of the image.

Figure 2. Figure 2 a & b – a) Right hand of the sitter before varnish removal. b) Same area after varnish removal. The red squares indicate the paint fragments discovered.

2

Information on the costume and its historical context was kindly provided in discussion with Dr. Xénia Ribeiro and Dr. Ângela Valério.

2. Materials and methods As noted in our previous paper [1] BEVA® Gesso-P is a commercially prepared infill material3, which when analysed, was found to contain an ethylene/vinyl acetate copolymer mixed with a synthetic resin, calcium carbonate and what appears to be an aluminosilicate. Additional materials noted in the datasheet are a pH buffer, oxidation inhibitors and UV stabilizers [4]. For the applications described in this paper the BGP was diluted prior to use with the addition of Shellsol A. Dilutions varied, but most often resulted in a loose paste slightly more liquid than toothpaste.

2.1. Working with BGP Hand building texture

In order to fill small gaps and ensure a level join between the painting and the replacement strip, dilute BGP was applied locally with a small spatula or brush and its dried surface was then textured to carry over brushstrokes and depressions from the painting for the eye to follow into the fill area (Fig. 3). In these small areas BGP was relatively easy to work with, allowing texture to be created by adding BGP on top of a dried infill or by carving into the dried surface with a scalpel, then partially dissolving the BGP with solvent to soften edges. Often a combination of both methods were used. The considerable drawback of BGP, that it is translucent during application, only

3

BEVA® Artist Gesso-P, from Kremer Pigmente GmbH& Co. KG, Hauptstr. 41-47 DE 88317 Aichstetten, Germany (www. kremer-pigmente.de).

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

167


XVII. Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

becoming white as it dries, was not a problem for these small infills.

Figure 3. a & b – a) Before infill of the interface between the painting and the replacement strip b) Same area, after hand built textured infill with BGP.

Casting a small textured fill

For the larger, shallow fills, initially the same method used for casting the replacement strip was used. A very thin film of BGP was cast on textured silicone moulds and then cut and applied to lacunae using fluid BGP as an adhesive. Unfortunately it proved extremely difficult to achieve an even surface of the correct height. Furthermore if the cast film was too thin it melted into the liquid BGP layer beneath.

Imprinting texture in-situ

The alternative, to first apply BGP evenly into the lacunae then to place a textured silicone mould on top with weights until the BGP dried, was not feasible since the silicone mould material (Duplosil®4) was highly sensitive to the solvents in the BGP. It distorted and swelled such that the texture in the mould was lost. However a solution to this problem was 4

168

Duplosil®, 9º-10º shore A, two components A and B. Simed, Dental equipment and products, Deffner & Johann GmbH (http://www.deffner-johann.de).

discovered while testing isolating varnishes for the BGP replacement strip in order to maintain its texture during reintegration with Gamblin Conservation Colors5. A barrier skin was created by brush coating the surface of the BGP with Paraloid B-72 (10% in acetone). This led to the realisation that Paraloid B-72 in acetone also formed an effective barrier to BGP solvents when it was applied to the silicone mould first. This allowed the Paraloid B-72 protected Duplosil® moulds to be used to imprint the texture on top of wet BGP that had been applied in the losses. With this method, thin layers of BGP were created with a small spatula (dental tool) directly into the loss, allowing each layer to dry in-between, until the BGP reached just below the painting’s surface. For the final layer, very fluid BGP was applied, then the silicone mould was placed on top and held under pressure with a flat board covered with weights until it had fully dried (Fig. 4). Although this method was effective, it is not entirely straightforward as, it can fail or require further local work by hand with the BGP. In this method the translucency of the BGP while wet added a further complication as it was difficult to assess the evenness of the last fluid layer which had to remain wet in order to accept the silicone mould’s texture. Using heat to effect thermoplastically induced texture on dried films of BGP was not possible since the Duplosil® moulds were too thick and heat resistant6. 5

Gamblin Conservation Colors, Gamblin Artists Colors Co PO Box 625, Portland, OR 97207 503.235.1945 (www. gamblincolors.com)

6

The modified BEVA® 371 method used by the Stichting Restauratie Atelier Limburg (SRAL), described in our RECH2 paper [1] does make effective use of heat to produce texture, however their silicone material achieves a much thinnermould.


XVII. Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

with no sign of forming a protective film. Two 10% solutions of Paraloid B-72 were tried, one in xylene, which disrupted the texture and another in acetone. This last option proved to be the best choice: the texture was not affected and the film produced a shiny, clearly visible coating.

Figure 4. Sequence from left to right: (a) 1st layer of BGP applied; (b) the layer after drying; (c) top layer of fluid BGP with silicone mould on top; (d) appearance of BGP after drying; (e) the final textured infill.

2.2. Preparing BGP for reintegration

As noted above, an important issue with BGP during reintegration is how to protect its textured surface. Since BGP remains sensitive to aromatic solvents used with many inpainting binders, including Gamblin Conservation Colors, the its surface can swell and lose texture during reintegration. In addition, since the loss was so large, an isolating layer was also necessary to allow revisions during inpainting. As summarised in Table 1, a series of different resins and solvents were applied by brush onto dried BGP films. A 20% solution of Laropal A81 resin dissolved in a mixture of Shellsol A (40%) and Shellsol D40 (60%) resulted in a loss of original texture and created a new brushed texture in the BGP surface. Replacing the solvent with isopropanol, was not a success: while the isopropanol did not affect the texture, it did not form an even film (deduced by the unevenness of surface gloss). A 10% solution of Regalrez 1094 in white spirits did not affect the texture but kept sinking into the BGP surface

Laropal A81 20%

Regalrez 1094 10%

Paraloid B-72 10%

Shellsol A (40%) and Isopropanol White Spirits Xylene Acetone Shellsol D40 (60%) Does not Does not Does not Affects the Affects the affect the affect the affect the texture texture texture texture texture Creates new Seems to Creates new texture of Uneven continuously texture of Even Gloss brushstrokes Gloss sink in brushstrokes Does not Does not seem to form an even form a film film (no shine at all)

Seems to form an even film

Table 1. Isolation varnishes tested over BGP.

The next step was to explore options for the inpainting material. These were tested on top of a strip of BGP with coated and uncoated areas of 10% Paraloid B-72 in acetone.Single and double layers with different inpainting materials and application methods were then applied. The materials tested included Plakka gouache7, Lascaux 4140 Medium for Retouching 20-508 (polyvinyl acetate in 50% solution with 35% ethanol and 15% acetone) and Gamblin Conservation Colors. Single layers of each were 7

Plakka Gouache, Extra Fine Quality; Royal Talens P.O. Box 4, 7300 AA Apeldoom, NL (www.talens.com)

8

4140 Medium for Retouching 20-50, Contents: Mowilith 20 (polyvinyl acetate) in a 50% solution with 35% ethanol and 15% acetone; Lascaux Colours & Restauro, Barbara Diethelm AG, Zürichstrasse 42, CH-8306 Brüttisellen (www.lascaux.ch)

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

169


XVII. Further Developments on the use of BEVAÂŽ Gesso-P infills and Solutions for Reintegration of a large loss

applied as well as a double layer system of gouache or Lascaux 4140 Medium with a glaze of Gamblin Conservation Colors.

2.3. Determining what belongs on the missing strip

In order to establish how the sitter’s right hand may have appeared, a valuable clue was obtained by tracing the outline of her left hand and inverting the image. It was surprising to find that the tracing fit almost perfectly onto the remaining outline of her hand (Fig. 5). This could only have occurred if the artist had also produced the hands in the portrait by inverting the image of one hand to create the other.When the tracing paper was inverted, a ring on her ring finger was seen to align with a fragment of darker paint on the remaining part of the right hand. This appears to be a strong indicator that a ring was also painted on the right hand of the sitter.

Digital reconstructions of possible positions for the right hand and for a fan were made. It was not possible to establish whether her fingers would have been extended or bent, and whether the fan was open, partially open, or shut. To explore these options a colleague was asked to pose holding a fan in various positions to help establish, given the information present in the painting, what was physically possible. As a result the following options were explored (Fig. 6). Ultimately there are limited choices regarding the position of both the hand and the fan based on the information which remains in the image. As for the style and colour of the fan itself, the answer is necessarily rather arbitrary, and in the final reintegration may only be suggested. In any case full documentation of the reintegration will accompany the painting when it is returned to its owner.

As noted above, costume experts had suggested that the sitter could have been holding a fan, and a small painted area which could be associated with its handle was discovered during varnish removal (Fig. 2b)

Figure 6. Two digital reconstructions of the hand with (a) fingers extended and (b) fingers bent

3. RESULTS and Discussion

Figure 5. Tracing paper with the outline from the left hand, inverted and placed over the sitter’s right hand.

170

A textured and well executed infill is crucial for an overall successful reintegration, since a poor fill will detract from even the most


XVII. Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

perfect inpainting [5]. For that reason, different approaches and methods of application for infilling with BGP were found in order to surmount the difficulties experienced during its use. The result is that the many positive properties which recommend its place in the conservators’ choice of infill materials can now be exploited.

flexible in the thinnest of films and accepts any texture very easily, from a mirror glass finish, to a complicated impasto; keeping the texture intact during reintegration required thorough testing to discover a solution. Fortunately the use of Paraloid B72 in acetone has proved an effective solvent barrier during the application of a range of inpainting materials.

From the inpainting materials tested, the system which appeared to give the best result is an underlayer such as gouache, to create a base colour, followed by glazing or top coats with Gamblin Conservation Colors. This allows the construction of the reintegration according to the layering seen on the painting itself, with the option of correcting application and colour without affecting the layer below.

Regarding the determination of what belongs on the painting’s missing strip, the discovery of the two tiny paint fragments which pointed to the presence of a fan and a ring on the sitter’s right hand was fortuitous, but would not have been interpreted correctly without the expertise of the curators at the costume museum, and the tracing paper exercise, which revealed the edge of the ring while also illustrating the artist’s original technique. For an overall images of the options for reintegration of the strip, digital reconstructions are not only useful as guides, but can also be available to the public, as well as researchers, to explain and demonstrate the range of possible interpretations other than the one chosen.

The chromatic reintegration of the replacement strip presents significant challenges given its size and the lack of any historical information on the painting prior to the damage. The methodology used, to consult costume experts, to trace the left hand, and to make digital reconstructions based on the remaining information from the painting and that provided by a live model, resulted in viable options for the final reintegration.

4. CONCLusions In conclusion, regarding the BGP, it can be an extremely versatile material when its handling problems are overcome. The main disadvantages in application are that fact that it requires toxic solvents, and it is transparent when applied in dilution. Although BGP remains III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

171


XVII. Further Developments on the use of BEVA® Gesso-P infills and Solutions for Reintegration of a large loss

REFERences [1] CARLYLE, Leslie; MARQUES, Raquel; CARDOSO, Isabel P.; BABO, Sara – Creating a Textured Replacement Strip for the Missing Lower Portion of an Oil Portrait: Problem Solving and Practical Solutions. The Picture Restorer. Vol. 45 (2014), pp. 44-52. (This publication was reprinted by kind permission from The British Association of Paintings Conservator-Restorers in the Proceedings from the 2nd International Meeting on Retouching of Cultural Heritage (RECH2), 2015. pp. 40-53.) [2] SEYMOUR, Kate; OCH, Jos – A Cold Lining Technique for Large-scale Paintings. In WOODCOCK, Sally, ed. – Big Pictures, Problems and solutions for treating outsize paintings. London: Archetype Publications, 2005, pp. 96104. [3] OCH, Jos; HOPPENBROUWERS, René - Mist-Lining and Low-Pressure Envelopes: An alternative lining method for the reinforcement of canvas paintings. Zeitschrift für unsttechnologie und Konservierung:ZKK, 17 (2003), pp. 116128. [4] BEVA® Gesso Description and Instructions for Use. Talas online. Available at: http://talasonline.com/ photos/ instructions/Beva_gesso.pdf[accessed 2014]. [5] DIGNEY-PEER, Shawn; THOMAS, Karen; PERRY, Roy; TOWNSEND, Joyce; GRITT, Stephen . The imitative retouching of easel paintings. In STONER, Joyce Hill; RUSHFIELD, Rebecca, ed. – Conservation of Easel Paintings. London and New York: ROUTLEDGE, 2012, pp. 607-634.

172


XVIII

Retouching methodology when a painting is composed of seveN compositions


XVIII.

Retouching methodology when a painting is composed of seveN compositions

Rūta Kasiulytė

Pranas Gudynas Centre for Restoration at the Lithuanian Art Museum

Rūdninkų Str. 8, LT-01135Vilnius, Lithuania

E-mail address: rutakasiulyte@gmail.com

Abstract The studied painting is composed of seven scenes. Its author is unknown, but the work dates to the late 18th century. Being of a large format it was brought to the restoration workshop without a stretcher and folded several times. Numerous layers of ground and paint had been lost. The main challenge was on how to find out the best methodology of retouching when apainting is so large and so damaged? During restoration the layers of ground and paint were strengthened. The painting’s edges were thickened with new strips of canvas. Retouching was conducted at several stages, concentrating on one composition at a time, and finally retouching the monocolour parts of the background that connected the adjacent composition. The methodology selected helped tomaintain the entirety of the painting at every stage.

Keywords Casein tempera; Mimetic retouching; Restoration primer; Retouching methodology.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

175


XVIII. Retouching methodology when a painting is composed of seveN compositions

1. Introduction This painting is the property of Šiauliai Aušra Museum in Lithuania. This is a religious picture, which found its way to the museum during the Soviet period (in 1958) and since then it has been kept in storage at the museum. Its author is unknown; the painting is dated back to the end of the 18th century. The picture is very interesting because its plot is rare in the history of painting in Lithuania. This is as though a picture in the picture, which contains as many as seven compositions. There are five wonderworking images of the Blessed Virgin Mary in the centre that were worshiped in the Grand Duchy of Lithuania. They can be recognised from the inscription made at the bottom of each image and the date of the coronation in each of them. At the top, among them, there is the image of the Holy Trinity and several saints are arranged at the bottom of the picture. It is probable that the picture was created for certain celebrations related to the worship of the Blessed Virgin Mary in different Lithuanian representations. It performed as though a poster-placard. The painting is large, 183x152cm. It was brought to the restoration workshops without a stretcher and folded many times. Its base was sewn up from two pieces of canvas and was deformed. (Figure 1) The painting layer was badly crumbled. The chemical analysis carried out showed that the picture had been painted in casein tempera. The layers of priming and paint are rather thin.

176

Figure 1. “Seven compositions”. 183x152cm. General view before restoration in raking light. Photographer Vilma Šileikienė.

2. MATERIALS AND METHODS First of all the painting layer of the picture was consolidated with sturgeon glue. At first it was sprayed with low concentration glue, and then it was glued with cigarette paper. The picture was kept in a special made camera to make it more elastic and then the consolidation of the layer of paints was finally finished. The support of the painting was consolidated with new borders and after the dry lining method had been employed, it was stretched on a new stretcher. The priming was carried out with sturgeon glue as binding material. The picture was primed gradually and each composition was primed separately. (Figures 2 and 3) The first application of the priming was on the


XVIII. Retouching methodology when a painting is composed of seveN compositions

middle part of the painting. It was evened up, and the excess was cleaned from the crumpled edges with cotton balls soaked in distilled water. Having completed this process, each composition was then retouched separately. Then another compositional group was primed. Finally, all losses were gradually primed and retouched in this way. (Figure 4)

Figure 4. Painting “Seven compositions”. General view during restoration in indirect light.The upper part of the painting is primed, the middle part is retouched, and the lower part is consolidated.

Figure 2. Painting “Seven compositions”. Fragment before restoration in raking light

3. RESULTS

Figure 3. Painting “Seven compositions”. Fragment during restoration.

Special attention was paid to the retouching of the picture. The mimetic retouching technique was used to retouch the lost places with watercolours. The layers of priming and paint are thin, the crumbling is very fine, abundant and merging, therefore when retouching, the paint had to be applied with a very fine brush and in one layer. This implied that the colour had to be the right shade so it could be placed in a single brush stroke, making the retouching process a difficult task. Retouching was carried out in stages: each composition was retouched separately leaving the monochrome background for last.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

177


XVIII. Retouching methodology when a painting is composed of seveN compositions

4. CONCLUSIONS The restoration of large size painting with great losses was problematic task in priming and retouching processes. The methodology chosen – first to apply priming and retouching to each composition and later to background – justified itself. It helped to achieve the integrity of the image in each stage of restoration. Besides, the restoration was carried out faster. (Figure 5)

Figure 5. Painting “Seven compositions”. General view after restoration in indirect light.

178


XIX

DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE


XIX.

DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE Sandra Šustić

PhD candidate, Faculty of Humanities And Social Sciences at the University of Zagreb, Ivana Lučića 3, HR-10000 Zagreb, ssustic@h-r-z.hr

Abstract When dealing with complex losses on the paintings from the 16th and 17th century the challenge is to evaluate the artist’s painting technique and its applicability in the retouching process. This kind of approach dates back to the teaching of the famous restorer and connoisseur Helmut Ruhemann and his insistence on following the methods and techniques of the original painter. However, the development of technical studies in the conservation field and an effective work of interdisciplinary collaboration, have greatly facilitated explorations of a painting’s inner structure and the way the artist has built it. In this context the author has considered two interesting case studies carried out at the Croatian Conservation Institute (HRZ – croat. Hrvatski restauratorski zavod). It was concluded that the analyses of the painter’s style and his use of elements and principles of art can lead to a harmonious integration of the paint layer that doesn’t interfere with a perception of the painting as a whole.

Keywords Mimetic retouching, Old Masters, Historical information, Technical studies, Elements of art.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

181


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

1. Introduction Restoration studio in Split was founded in 1954, owing to the efforts of Cvito Fisković - one of the most prominent Croatian art historian and conservator. In the early days, the theoretical principles of famous Italian art historian and critic, Cesare Brandi, affected the everyday practice and visible retouching was firmly established as the major trend of the studio. Conservators were practicing tratteggio using highly reversible materials - gouache and watercolor. However, during the sixties and the seventies, these materials were substituted with less stable ones such as oil and resin medium. Due to the collaboration with conservators from Zagreb and Belgrade, the practice of the eighties shows frequent use of wax in lining procedure. Gradually, this material has found its purpose in retouching as well; the use of carnauba wax mixed with pigments predominated among other mediums. The practice of the eighties also records new techniques of reintegration - neutral tone and pointillism. At the end of the 20 century, mimetic retouching became the main retouching technique at the Restoration studio in Split. Conservator Branko Pavazza, today’s head of the Department, implemented new knowledge gained from his training in Venetian institutions. Colla di pasta has radically minimized the use of the age-long wax in lining. In addition, the oil and wax medium, were finally abandoned, and water based paints came back into retouching practice. The collaboration with Florentine conservator Stefano Scarpelli was the second advancement of the nineties. th

182

Scarpelli presented the technology of a new high-quality and reversible natural resin Canada balsam, which gave excellent results in mimetic retouching of Old Master paintings. [1] In today’s practice, the development of analytical methods and interdisciplinary studies, have considerably facilitated mimetic retouching at the Institute. While connoisseurship can suggest the quality and extent of retouching necessary for reestablishing potential unity of the composition [2], scientific analysis of the physical structure and chemical nature of the painting influence the selection and the use of the materials during the retouching process. Thus, the first part of this article aims at describing the main stages of preliminary research used in mimetic retouching, while the second part deals with this issue in a practical way and presents two retouching projects carried out at the HRZ Department in Split.

2. MATERIALS

AND METHODS OF PRELIMINARY RESEARCH IN RETOUCHING

When dealing with major loses on the paintings of liturgical importance the challenge is to evaluate the artist’s painting technique and its applicability in the retouching process. Therefore, it is desirable to conduct an interdisciplinary research of the treated painting and to collect all relevant information that can be linked to the artist’s original intentions. At HRZ - Department in Split, this kind of research involves close collaboration of various specialists, namely, conservation


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

scientists, chemists, art historians, radiologists, etc. The results gained by these investigations can serve as complementary material in understanding original methods and techniques of the painting’s construction, or, in other words, the artist’s intention, which is essential for defining the precise strategy in mimetic retouching. Currently, two techniques of mimetic retouching are practiced at the HRZ - Department in Split: direct mixing of colors in the palette and interlayering reconstruction of the original. Either way, the aim is to completely eliminate the lose effect and to direct the perception of the observer on the whole of the painting and not on the result of the intervention. [3] Water based media in underpainting and resin media for glazing and scumbling, or, in other words combining media, is the most common choice in interlayering retouching construction at HRZ - Department in Split. There are several stages of preliminary research that are consequential for conservator’s decisions in mimetic retouching of complex losses: analyses of the paint layer in the visible spectrum, technical studies, historical information and study of the elements of form. The results gained by these investigations serve as complementary material for understanding original methods and techniques of the painting construction, or, in other words, the artist’s intention, which is essential for defining precise strategy in retouching. [1] In visual and microscopic examination, the artist’s original technique and the effect of the loss on the whole of a painting are observed and documented. Important details such as

patterns of craquelure, the superposition of the paint layer and preserved fragments - within and around the loss - are examined in close detail. The observations under the raking light reveals further particularity, especially the manner and the direction of the brush stroke, as well as the viscosity of the paint. Great deal about the artist’s intention is comprehended from such examination. For example, the use of a heavy, textured impasto, can indicate the painter’s intent to suggest the movement in a certain area of the painting. The cross sections of the paint layer provides a valuable insight into chemical compound, arrangement, thickness and texture of sampled areas in the painting. Furthermore, it indicates the painter’s technique and swiftness of his painting performance according to the sharpness of the borders between each layer. Collected data from the cross section analyses are backed up with results of the multispectral imaging. Infrared reflectography, for example, can detect the original underdrawing method and help to understand the basics of the compositional elements. Due to the high X-ray absorption of the pigments with heavy metals in their structure, X-radiograph is used to inform us about the underpainting methods. This information can be indicative when dealing with certain special effects of the paint layer such as luminosity of the skin tones or drapery that can only be achieved with precise copying of the underpainting methods. [4] While technical studies reveal the list of materials within the painting’s structure, study of the historical treatises inform the conservator of their use. This investigation can

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

183


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

improve the perception of certain paint effects and provide precise means of achieving them.

helping tool that even the Old Masters have used to generate their figural compositions.1 Of

When dealing with damages on religious Old Master paintings, the study of iconography of presented symbols, attributes, or emblems leads to precise identification of the Christian saint and his features. Moreover, archive evidence of the former state of the painting and the study of the related works (such as drawings, cardboards, sketches on the subject by the master, or copies and variants of the work) helps to understand the continuity and the progress of the damaged painting.

course, resemblance of a model to a damaged figure in age and proportion is desirable in this process. [8]

The formal optical elements upon which Old Masters have painted their figures (line, shape, color, light and dark, mass, volume, texture and space) may be corrupted by the loss in the paint layer. In order to restore them correctly conservator has to understand the principles of anatomy, perspective and chiaroscuro. This kind of study is especially relevant when dealing with complex losses that contain the missing body parts. Knowledge of the body form improves conservator’s eye for the form and detail [5], while delineation of the original perspective within the painting leads to precise location of the missing body part [6]. The intensity of the damaged chiaroscuro will depend on the source, direction, hue and strength of the present light in the painting [7]. Yet, it will also be affected by the anatomical features of the figure such as underlying fat, epidermis smoothness, superficial muscles, bone protrusions, as well as with perspective type that impacts the posture of the figure. Finally, the use of live model in the reconstruction process is regarded as a relevant 184

3. CASE STUDIES and Discussion The baroque painting of Baldassare D’ Anna depicting St. Jerome and the saints had suffered a major loss in the lower area of the composition. While some parts of the lost composition were rather clear, missing foot of St. Peter, required more research (Image 1.)

Figure 1. Lower area of the painting depicting Saint Jerome and the Saints from the 17th century (oil on canvas, 152 x 258 cm), Church St. Sunday, Island Hvar, Croatia. Before restoration treatment. Photographic archive of the Croatian Conservation Institute. Credits: Renata Džaja.

Elements such as anatomy and perspective were analyzed within the character, as well as in other figural parts of the composition. 1

The painting was restored in the Croatian Conservation Institute, Department in Split, in 2007/08. Conservators engaged on this project were: Branko Pavazza – head of the Department in Split, Renata Džaja, Sandra Šustić - associate in retouching.


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

The eye level was traced slightly below St. Jerome’s left knee; as well as the vanishing point of the floor lines that are perpendicular to the picture plane. These lines correspond to the position of the St. Jerome’s feet as well as with the position of the preserved pieces of the thumb of St Peter (Image 2.)

linear perspective in the painting as well as the tip of a thumb in a preserved paint layer. Prior to the final retouching, the anatomical drawing of the foot was made. Chiaroscuro was defined according to primary light source in the painting, directed from the upper left corner. The crucial part of preliminary research carried out for the complex intervention of retouching on the painting Virgin Mary and Child with St. Lawrence and St. Nicholas from 17th century was the study of the basic elements and principles of the composition.2

Figure 2. Delineation of the perspective type. Photographic archive of the Croatian Conservation Institute. Credits: Sandra Šustić.

Physical appearance of the male figures, especially in the case of St. Jerome, reveals the painter’s awareness of superficial muscles, tendons, and bone pervades. Thus, the reconstruction was based on the detailed anatomical research. Moreover, the live model was placed in the exact position of the figure and several different positions of the foot were explored. This method demonstrated that there was only one position of the foot that provided balance to a model and it was correctly matched with the lines of the original

The largest loss of the painted layer included lower body parts of a winged angel located in the upper area of the composition. Besides the lower line of the left foot, partially discernible on the preserved remains of the paint layer, the angel’s legs were completely lost. Due to the liturgical importance of the painting in the Church of Saint Lawrence in Šibenik, where it is placed on the main altar, the reconstruction of the damaged composition was an eligible part of the restoration process. Although the use of linear perspective was rather vague in many portions of the composition, the vanishing point was detected near the foot of St. Lawrence, and the imaginary line of the lower part of the missing foot was easily located (Image 3).

2

The painting was restored in Croatian Conservation Institute, Department in Split, in 2010. Conservators engaged on this project were: Branko Pavazza – head, Julija Baćak, Branka Martinac, and Sandra Šustić - associate in retouching.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

185


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

Figure 4. Anatomical drawing of the legs. Photographic archive of the Croatian Conservation Institute. Credits: Sandra Šustić

Figure 3. Madonna and Child with St. Lawrence and St. Nicholas from the 17th century (oil on canvas, 120 x 270 cm), Church of Saint Lawrence Šibenik, Croatia. Photograph taken after the execution of conservationrestoration treatment. Photographic archive of the Croatian Conservation Institute. Credits: Branka Martinac. Delineation of the original perspective. Credits: Sandra Šustić.

However, the form of the foot was still questionable, and thus it was necessary to perform additional anatomical research coupled with the use of a live model as a helping tool. Observations of the preserved angels on the painting have shown that the angularity of the bones is suppressed; instead the painter has emphasized the interior mass of the limbs. Two year old baby was placed in the same position as the damaged figure, and his legs were photographically documented. The anatomical drawing was made and tested within the composition until the unity of the form has been matched with the whole of the painting (Image 4). 186

Finally, the study of the original chiaroscuro of the painting has shown that the painter used one-source lighting that came from the upper left to define the form. Areas of highlight, light, shadow, core shadow, reflected light, secondary highlight, and cast shadow were distributed according to the direction, hue and strength of the primary light source. The intensity of the chiaroscuro on the missing limbs was affected by the original perspective and anatomical features of the figure. The accent was on the interior mass of the limbs. A thorough examination of the paint surface through a binocular microscope gave insight into the painter’s technique. The brush strokes showed that the angels were painted on the top of the blue sky area. Furthermore, the use of wet-in-wet technique was detected on the surface of the flesh tones. Thus, the retouching was performed following the same layering structure and method of application (Image 5).


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

creating any unpleasant effects. If the final appearance of the restored painting does not invoke the doubt of the composition as a whole, then the application of the research results was efficient. Figure 5. Building the layering structure. Photographic archive of the Croatian Conservation Institute. Credits: Sandra Šustić

Chiaroscuro was almost entirely obtained in underpainting stage, however, the antique appearance of the paint layer was accomplished in final glazing. The retouching of the missing foot was executed with an idea to restore the unity of the form but also to leave the fine details of the foot undefined and suggestive (Image 6). [9]

Figure 6. Reconstruction of the angel’s legs. Photographic archive of the Croatian Conservation Institute. Credits: Sandra Šustić

4. CONCLusions The development of analytical methods and interdisciplinary studies, have considerably facilitated mimetic retouching at HRZ. This study has emphasized five stages of investigation that affects conservators decisions in retouching: analyses of the loss type and its effect on the whole of a painting, examinations of the paint layer in the visible spectrum, technical studies, historical information and the study of the elements and the principles of art. The results of two complex retouching projects carried out on paintings of liturgical importance have demonstrated that if a conservator respects the genuine artist’s method of interlayering structure of the paint layer, the matching in retouching process can be much easier to accomplish. In addition, analyses of a painter’s style and his use of the elements and the principles of art can lead to a harmonious integration of the paint layer that doesn’t interfere with the perception of the painting as a whole.

The main concern regarding this complex retouching is whether there are any disturbing effects within the reestablished composition. With respect to the painter’s technique, considerable effort has been made to avoid III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

187


XIX. DECODING OLD MASTER PAINTINGS: EXAMPLES FROM THE CROATIAN CONSERVATION INSTITUTE

REFERences [1] ŠUSTIĆ, Sandra - Brief handbook about mimetic retouching, Porto: Arvore, 2015. [2] BRANDI, Cesare - Il Trattamento delle lacune della gestalt psychologie. XX International Congress of History of Art. Nova Iorque: [s.n.]. 1961, pp. 149-151. [3] BAILÃO, Ana - Application of a methodology for retouching. CeROArt [En ligne], (2010) http://ceroart.revues.org/1603. [4] MOHEN, J. P., et al. - Mona Lisa, Inside the painting, Harry N. Abrams inc, New York, 2006. [5] SIMBLET, S., DAVIS J. - Anatomy for the artist. United Kingdom: Dorling Kindersley Publishers LTD, 2001. [6] ANDERSEN, K. - The geometry of an art: the history of the mathematical theory of perspective from Alberti to Monge. Springer, 2007. [7] OLSZEWSKI, E. J. - Distortions, shadows, and conventions in sixteenth century Italian art. Artibus et Historiae, Vol. 6, n.º 11 (1985), pp. 101-124, 118. [8] WYLD, M. - The Restoration History of Holbein’s ‘Ambassadors’National Gallery. Technical Bulletin, n.º 1919 (1998), pp. 1-25, 22-25. [9] ŠUSTIĆ, Sandra - Umijeće retuširanja u teoriji i praksi, Portal, the Yearbook of the Croatian Conservation Institute, n.º 2 (2011), pp. 197-212.

188


XX

Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material


XX.

Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

Sarah Maisey (1) (1) Royal Museums Greenwich; Park Row, Greenwich, London, SE10 9NF; SMaisey@rmg.co.uk

Abstract Major compositional losses in paintings present conservators with ethical and practical dilemmas regarding any reconstruction that might be applied. However, where sufficient visual evidence of missing material exists from alternate historical sources, it may be possible to reconstruct missing areas of paintings. This approach can be trialed digitally prior to carrying out practical work. This paper will investigate the potential of this technique exploring two examples. Firstly, recent work carried out on an 18th century marine painting by Dominic Serres from the National Maritime Museum, Greenwich will be described. Following historical research, photographs of a ship model were used to digitally reconstruct the same vessel within the painting, which had been almost obliterated by historical damage. The second, more complex, example involves a flood damaged John Martin painting from the Tate collection which was restored in 2011. The painting had sustained a major loss (approximately one fifth of the canvas) following a flood in 1928 which had obliterated the heart of the composition. In this case a digital reconstruction was created by cross referencing visual material from a schematic print, another version of the work and an old photograph. This paper will examine how these sources were identified and utilised, how the digital reconstructions were created, and how the practical painted reconstructions drew on them. The benefits of creating the digital image, enabling discussions with fellow conservators and curators regarding the ethics of such work, will be explored.

Keywords Digital; Reconstruction; Composition; Painting; Historical sources.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

191


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

1. Introduction Large compositional losses in easel paintings are thankfully a relatively rare thing. Whilst losses resulting from such things as flaking and abrasion can be widespread, they don’t usually cover large areas, and represent a challenge to the conservator only in terms of matching

source material. This paper will therefore outline two case studies where digital reconstructions have been used in this way.

colour, gloss and texture. However, where compositional losses do occur, they can severely compromise the aesthetics of a painting. They draw the viewers’ attention, disrupt the flow of the image and its narrative and usually completely undermine the artists’ intention. They can also obliterate important narrative information that viewers need to understand a painting. Clearly, for ethical reasons, large reconstructions can only be considered where there is good, reliable and detailed knowledge of what went in the gap. In some cases this may be straightforward, for example where there is a good quality photograph of a painting before damage and loss was sustained (reference). However, in other cases it may be necessary to locate and use alternate visual sources that don’t directly and seamlessly translate to the missing section of the composition. Where this is the case it can be useful to preview the reconstruction, in advance of carrying out any actual visual intervention on the artwork. This can firstly help the conservator in determining how the reconstructed area should look. It can also be used as a tool to facilitate collaboration with curators and other colleagues, both in terms of promoting discussion over the form the reconstruction should take, and in terms of finding relevant 192

Figure 1. The Capture of Geriah by Dominic Serres 1771, after cleaning and varnish removal but before retouching. The horizontal dark strip in the bottom left corner of the painting corresponds with the repainted canvas insert. Photo © National Maritime Museum, Greenwich, London.

2. CASE STUDY 1: “THE CAPTURE OF gERIAH” BY DOMINIC SERRES

2.1. Background to the painting

The painting illustrates the destruction by the British fleet of Geriah, a pirate stronghold on the Malabar Coast. Geriah’s notorious chief, Talagree Angria, had been coordinating attacks on the East India Company’s trade ships until late in 1755, when an expedition of Royal, Company and Mahrattan ships was organised to capture the pirates and destroy the fort. Paintings illustrating such naval actions were valued by their patrons more for commemorating the specific event in question than as aesthetic objects in their own right. Consequently accuracy in terms of the detailed rendering of specific ships and actions


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

took a high priority. Dominic Serres was an artist venerated for his skills in accurately documenting such events.

2.2. Condition and initial conservation

The painting was treated in preparation for its inclusion in the National Maritime Museum’s Traders gallery in 2013. Before conservation the painting was obscured by a layer of discoloured varnish and ingrained grime, as well as extensive areas of mismatching and crude overpaint evidently applied over several campaigns. In particular there was a large area of non-original but historic paint in a substantial horizontal strip along the lower portion of the painting (figure 1). This appeared to be over an area where the original canvas had been totally lost and an insert was inserted prior to an early lining procedure. Most of this area covered simple sections of the sea (aside from a few masts and rigging of the smaller boats) and was therefore relatively straightforward to mimetically retouch in a way that was sympathetic to the original. However the edge of the damage did extend to the prow of one of the ships at the far left (figure 2b). Prior to conservation this had evidently been retouched in a crude manner which bore no resemblance to the form which had originally been there (figure 2a). The area requiring reconstruction in this case was a relatively small area located in the periphery of the painting. It could be argued that reconstructing the area with a generic ship form, albeit one that was less crude than the pre-existing reconstruction, would not have severely compromised the function of the painting to most members of the public viewing it today. Nevertheless it was felt

that if a more specific, accurate reconstruction could be achieved it was worthwhile trying to do this. There were several reasons for taking this view. Firstly it would honour the artist’s intention since Serres work historically relied so heavily on accuracy. Indeed it was notable that all the other ships in the painting were rendered in a highly detailed and recognisable way. Secondly, whilst the majority of the public would still be able to appreciate the painting with a generic reconstruction, a subset of visitors to the National Maritime Museum take a special interest in the form of the specific ships and actions. For these viewers the accurate rendering of all the ships would be important. Finally the National Maritime Museum has a wide array of specialist resources and curatorial expertise on which to draw. Having these factors on hand at the time of restoration not only encouraged more curatorial participation in the project, it also made accessing and using the resources discussed below more straightforward than it might otherwise have been.

2.3. Obtaining source material

The design of ships from the 18th century varied, so in order to create a reasonable reconstruction of the prow it was first necessary to identify the ship in question. With curatorial help it was possible to identify most of the ships in the picture by reference to a contemporary engraving by artist M. Hore. Although the ships in Hore’s print are not rendered in the level of detail seen in Serres’ painting, the basic elements of their design were apparent and the number of guns on most of them was listed in a key below the main image. By cross referencing this visual and documentary information with what could be seen in the

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

193


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

painting it was possible, through a process of elimination, to pinpoint the ship in question as the “Bridgewater”. From this, the National Maritime Museum’s curator of ship models, Simon Stephens, was able to identify the specific model (also in the Museum’s collection) on which the Bridgewater was based.

2.4. Undertaking the reconstruction

The ship model provided a detailed and reliable visual reference on which to base the reconstruction. A simple digital reconstruction was created by taking a photograph of the model from the appropriate angle, scaling it to the right size, and inserting it digitally into an image of the painting using Photoshop (figure 2c). When it came to executing the painted reconstruction (figure 2d), it was fairly straightforward to infer the appropriate colours and handling by examining the other ships in the picture. This meant that no sophisticated manipulation of the digital image was required in advance to determine features such as the specific lighting angles and brushstrokes. As such the digital reconstruction in this case was quick to create and only needed to serve as a visual reference for the shape and relative scale of the form. Given the small size of the painted reconstruction in this case, the retouching materials and methods employed were the same as that used on the rest of the painting (a standard mixture of dry pigment mixed with MS2A resin in white spirit).

194

Figure 2. The Capture of Geriah by Dominic Serres (1771). Detail of the ship coming into the left of the painting a) Crudely restored before conservation b) After varnish removal with damage and underlying non-original paint exposed c) With the photograph of the ship model digitally inserted d) After reconstruction. Photos © National Maritime Museum, Greenwich, London

3. CASE STUDY 2: “THE DESTRUCTION OF POMPEII AND HERCULANEUM” (1821) by John martin

3.1. Background to the painting

The second case study presents a more complex example where it was necessary to reconstruct an extensive area in the focal point of a painting. The work was carried out by the author during a fellowship at Tate Britain between 2010 and 2011, and represented a major undertaking in terms of time and resources. The painting, depicting the ancient Vesuvian eruption over Pompeii and Herculaneum, is an early and significant example of John Martin’s “apocalyptic sublime”. It was badly damaged in 1928 when the Thames burst its banks and


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

water flooded into the lower galleries of the Tate. The painting was submerged, detached from its stretcher and ripped into pieces. About one fifth of the canvas, covering an area of the composition where the volcano itself would have been, was never recovered.

3.2. Condition and initial conservation

Documentary evidence [1] indicates that the painting was in a poor and neglected state even before the flood. When conservation began in 2010 it had numerous structural problems including extensive flaking throughout; multiple tears and punctures and severe deformations. The image was virtually unreadable under at least seven layers of dirt and discoloured varnish, plus encrusted dirt on the surface, not to mention the huge area of missing canvas. The reconstruction discussed here was the last aspect to be addressed, but the structural work, cleaning and retouching constituted the bulk of the treatment time and has been written about elsewhere [2,3].

3.3. Visual sources

When treatment began the initial aim was to make the painting structurally sound for display and for what remained of the original to be as legible as possible. Given the extent of the loss, it was never envisaged that the painting would be able to function as a work of art, and therefore the objective was to display it in the 2011 “John Martin: Apocolypse” exhibition as an archival document only. Whether this would have meant some sort of “neutral” tone, an outline impression, or an inserted version of one of the visual sources discussed below was not determined from the outset. In any case it was assumed that whatever went in the missing area would serve to indicate, rather than simulate, what had originally been there. However initial results after cleaning (figure 3), along with closer examination of the visual sources indicating the content of the missing area, prompted the creation of a digital reconstruction to determine if it was possible to digitally simulate how the painting would originally have looked.

The visual sources included:

Figure 3. The Destruction of Pompeii and Herculaneum by John Martin (1821). After cleaning and varnish removal. Photo © Tate

1) Another, smaller and later, version of the painting by John Martin, commissioned by Sir John Leicester and now housed in Tabley House, Cheshire. The work does not exactly match the original in terms of proportion, composition and paint layer build up, but is sufficiently close to the original to represent a useful source.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

195


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

2) A schematic, black and white, outline sketch of the work, also by John Martin. This was printed in Martin’s original 1822 exhibition catalogue which was centred on the painting [4]. It was originally intended to serve as a key, listing the major figures and features in the composition. 3) A low resolution, black and white reproduction of a photograph of the painting taken prior to the flood which had been published in Mary Pendered’s 1923 monograph on John Martin (see reference 1). The original photographic print and negative had since been lost and the photograph was evidently poorly lit so no details are visible. However the general forms of the landscape and smoke clouds are visible in the image.

No single one of these visual sources alone offered sufficient information on which to reliably base an accurate reconstruction. However, together with visual information discernible from what remained of the original, and in combination, they enabled an accurate picture to be determined. Therefore where one image lacked the appropriate information, another was able to provide the reference needed (see Table 1).

Table 1. Strengths and weaknesses of the different visual resources Source:

Provides visual information on:

Lacks visual information on:

Tabley house copy

- Scale inaccurate - Detail and overall Approximate form present but colour and tonal unreliable variation - Colour and tonal variation imprecise

Schematic print

Detail and form of individual features

- Colour and tonal variation absent

Reproduction of old photograph

Overall form and relative scale

- Colour absent and tonal variation poor

Original

Exact colour and layer build-up - Missing content of surrounding areas

- Scale inaccurate

- Detail indiscernible

3.4. Creating the digital reconstruction

The reconstruction was carried out in Photoshop with the help of staff from Tate’s photography department. The full digital reconstruction (figure 4) was created by inserting and manipulating the Tabley House version, referencing the other versions and the original to ensure that the forms, details and colours matched correctly. This was a complex process, taking approximately two weeks of full time work to complete. Curators and other colleagues were consulted throughout the process to ensure that what was inserted reliably represented what would have been there. On seeing the completed digital reconstruction the lead curator and others involved in the exhibition were keen to see if an actual painted reconstruction could be justified. Given the extent of the area to be reconstructed this was not a decision that was taken lightly. Various

196


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

colleagues, art historical experts and members of the public were consulted on the issue. All were shown the digital reconstruction and given a full explanation of the basis on which it had been constructed. Although opinions were not totally unanimous, the overwhelming majority of people in all categories agreed that a full reconstruction was the favourable option, given the weight of the visual evidence and the benefits of enabling the painting to regain its original, dramatic impact.Added to this an eye tracking study was carried out indicating that an overly distinctive reconstruction or a simple neutral tone would severely disrupt the way viewers looked at the work [5].

Figure 4. The Destruction of Pompeii and Herculaneum by John Martin (1821). Digital reconstruction. Photo Š Tate

The final decision was therefore to undertake a reconstruction which blended seamlessly with the original from a normal viewing distance but was discernible up close. This would enable the painting to be appreciated much as it once had been, without deceiving the viewer as to what was original and what was not. Moreover it was decided that didactic material should be displayed next to the painting explaining its true state and history. It is unlikely that

deliberations relating to whether to undertake such a detailed reconstruction would have been made if curators had only had the opportunity to view the visual sources outlined above as separate images. Therefore the digital reconstruction was key in allowing those involved to confidently reach a decision.

3.5. Creating the painted reconstruction

The digital reconstruction proved invaluable when creating the actual painted reconstruction. An image of the former was printed to the correct size and displayed on a board next to the painting throughout the process so it could be constantly referred to and copied. Various painting materials and application methods were considered. After much experimentation and testing, Golden Open Acrylics were selected on the basis of their non-toxicity and their slow drying qualities which were effective in simulating Martin’s wet in wet oil painting technique. Further details of the painting materials and methods used to create the reconstruction have been written about elsewhere [6]. In the final reconstruction (figure 5) fine details and strong contrasts were slightly toned down so as not to draw undue attention to the reconstruction and to make subtle distinctions with the original on close inspection.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

197


XX. Retouching and reconstruction of major compositional losses in paintings: The use of digital reconstructions based on related historical material

REFERences [1] PENDERED, Mary John Martin, Painter: His Life and Times, Hurst & Blackett, London 1923 [2] WADE, Nancy (conference review) - Traditions and Advances in the Structural Repair of Canvas Paintings (Friday 30th September 2011) The Picture Restorer, No.40, Spring 2012 pp. 10-19 [3] MAISEY, Sarah - The conservation of ‘The Destruction of Pompeii and Herculaneum’ In MYRONE Martin, ed. John Martin: Apocalypse, Tate, 2011 pp. 113-115

Figure 5. The Destruction of Pompeii and Herculaneum by John Martin (1821). After treatment. Photo © Tate

4. CONCLusions As the two above case studies demonstrate, digital reconstructions can enable conservators to manipulate and preview a reconstruction before actually applying it to a painting, whilst at the same time cross referencing different visual resources. Moreover they can facilitate discussion and collaboration between colleagues and experts both in terms of locating visual sources for a potential reconstruction, and in terms of determining its nature, form and appropriateness.

198

[4] MARTIN, John A Descriptive Catalogue of The Destruction of Pompeii & Herculaneum; with other Pictures, Painted by John Martin, now exhibiting at the Egyptian Hall, Piccadilly London, 1822 [5] MAISEY, Sarah, SMITHEN, Patricia. VILARO SOLER, Anna and SMITH, Tim. J. - Recovering from destruction: the conservation, reintegration and perceptual analysis of a flood-damaged painting by John Martin.’ In: ICOM-CC 2011 16th Triennial Conference, 19-23 Sep 2011, Lisbon, Portugal. (CD ROM) [6] MAISEY, Sarah - Reconstructing the Volcano: Reintegrating an Expansive Loss on John Martin’s ‘Destruction of Pompeii and Herculaneum’ In: The Picture Restorer, No.40, Spring 2012, pp. 20-22


XXI

Filling as retouching:

the use of coloured fillers - in THE retouching of contemporary matte paintings


XXI.

Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

Silvia GarcĂ­a FernĂĄndez-Villa (1)

(1) Complutense University; Faculty of Fine Arts, Calle Pintor el Greco, 2. 28040 Madrid (Spain) sgfv@ucm.es

Abstract Contemporary paintings - characterized by new textures, unvarnished surfaces or matte finishes - have new aesthetic values that should be strictly respected by conservators. This often leads conservators to establish unconventional treatment methodologies and materials that include the retouching of areas with losses. This research presents the case of the retouching process carried out on several large paintings by the artist Manuel Padorno (1933-2002), considered one of the most important Spanish painters in the second half of the 20th century. Because of his creative process - distinguished by his freedom in the use of materials and techniques - some of his paintings now have significant conservation problems. This damage includes large losses and major cracks that have required unconventional retouching due to their particular shine, volume and saturation characteristics. In this case, the retouching of some large losses located in highly saturated and matte areas (some of them made up of synthetic gesso impastos) required the use of coloured synthetic fillers, instead of two separate layers of stucco and retouching, as the tested samples provided a glossier or more satin finish which prevented complete visual integration at the required level of saturation. The retouching methodology includes the preparation of coloured filler samples - using different synthetic reversible binders - to obtain an exact match not only in terms of colour, but also shine. The results showed that the use of these coloured fillers produces extremely matte and saturated colours that can be retouched afterwards if necessary. Wet-on-wet application, which produces complete visual re-integration in the original impasto areas, can also be achieved.

Keywords Retouching; Contemporary Painting; Filler; Acrylic.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

201


XXI. Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

1. Introduction Retouching contemporary paintings often requires new methodologies adapted to the unique qualities of the painting in question [1, 2]. This is the case of the retouching process carried out on three large paintings painted by Manuel Padorno (Santa Cruz de Tenerife 1933 - Madrid 2002). Padorno’s artistic legacy is full of poetry and the Urban Nomad series is essentially influenced by Mondrian, Monet, Giotto, Piero della Francesca, constructivist reticulate and abstract expressionism and is characterized by colour fields [3, 4]. The treated works belong to the aforementioned Urban Nomad series, begun in 1969 [5]. The treated paintings include the following: 1. Urban Nomad 66, 1980. Acrylic, vinyl paint and mixed media on cotton canvas. 162x102cm. 2. Urban Nomad 18. Giotto Series (CE0157) 1981-82. Oil, acrylic and mixed media on cotton canvas. 210x150cm. 3. Urban Nomad (CE0106) 1979. Acrylic and mixed media on cotton canvas. 210x160cm.

Manuel Padorno’s creative process during this period was specially defined by his freedom in the use of materials and techniques; this approach led to technical problems of adherence on the paint layer, as sometimes acrylic or vinyl dispersions are used on top of oil layers. Because of this, the damage caused includes large losses and major cracks.

202

Figure 1. Large losses and major cracks shown on the Urban Nomad (CE0106) (above) and Urban Nomad 66 (below) paintings by Manuel Padorno. © Silvia García Fernández-Villa.

Before treatment, the set of paintings were in a critical condition: losses located in large impasto areas required unconventional retouching due to their particular shine, saturation and volume characteristics. Most of the original surrounding paint areas had a matte finish and wet-on-wet application, with two or more colours mixed together (fig.1). Other areas were mainly colour fields – a characteristic feature of abstract expressionism - and therefore required mimetic retouching. Consequently, special materials and an adapted methodology are necessary in the retouching of this set of paintings.


XXI. Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

2. Materials and methods As mentioned above, the original surrounding paint has a wet-on-wet application (mixing two or more colours together), matte finish, high colour saturation and large impasto. The final retouching materials and methods should therefore include all of these features in order to achieve complete re-integration of the retouched areas. In the context of this research, different kinds of reversible and stable retouching materials have been tested: The first group of retouching samples are made up of the two typical layers: the first one made up of a stucco ground and the second consisting of a top coat of inpainting layer.A ground made up of traditional stucco based on rabbit skin glue (CTS) previously hydrated at a 1:10 ratio is thus prepared, to which carbonate sulphate is added until the required viscosity is achieved. While still warm, the stucco is applied in 3 coats with an intermediate drying time of 12 hours. Different retouching layers are applied to the stucco: the first sample is carried out with watercolour (Horadam® Aquarell, Schmincke), a completely reversible and soluble material in water formulated with a Kordofan Gum Arabic and Ox Gall base. In this case, it is necessary to apply several coats of aquarelle until the high colour saturation shown by the original paint layer is achieved. This is a significant disadvantage, as the top layers re-solubilise those applied previously. The second sample is Gustav Berger’s O.F.® PVA Inpainting layer. This is prepared with G. Berger’s O.F.® PVA Inpainting Medium, a PVA-based concentrated retouching medium in a 35% solid solution to which the

desired pigment is added, depending on the colour of the selected area. The solution should be diluted in ethyl alcohol (1:4) and is therefore not particularly suited to most acrylic paintings, which are usually soluble in alcohol, as is the case of the treated paintings. Inpainting sample number 3 is prepared using Gamblin Conservation Colours, an excellent and stable inpainting colour with a low molecular weight resin binder that provides a high saturation colour. The last inpainting sample is a gouache tempera layer (Talens Gouache Extra Fine Quality), and colours with high lightfastness (tested in accordance with ASTM Standards D4303) are selected according to the required area. The second set of inpainting samples includes different kinds of coloured fillers: for the gloss measurement samples, Maimeri 374 Cobalt Blue Deep pigment is added to each of the fillers in all cases until the required saturation is reached. The first filler is a pigmented Modostuc® (commercial formulated filler by Plasvero International), which is water soluble and reversible and has a viscosity highly suitable for the achievement of the required impasto. The second sample is prepared with pigmented Beva® Gesso (Kremer Pigment), a stable and flexible commercially formulated filler which is reversible with heat or low aromatic hydrocarbon solvents. The last sample is a coloured Mowilith® 5/2 (CTS) filler prepared with calcium carbonate (ratio 1:3) and the pigment mentioned above. Mowilith® 5/2 is an aqueous dispersion of a copolymer based on vinyl acetate and maleic acid butyl ester that contains no plasticizers.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

203


XXI. Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

The first parameter evaluated on the samples was their ability to provide the required aesthetic and surface finish, in order to provide a wet-on-wet application and obtain the required texture. Not all the samples are suitable for providing both features: for example, the fast drying time of watercolour, PVC and Gamblin colours inpainting means that wet-on-wet effects cannot be achieved. Only pigmented Modostuc®, pigmented Beva Gesso® and pigmented Mowilith® DMC filler are appropriate (table 1). Traditional retouching samples which include two layers (first a layer made up of the stucco filler and then a top coat made up of the colour retouching layer) are not recommended, as they cannot provide the required texture. Even if these inpainting layers are applied on highly textured stucco, the result does not resemble the original impasto, as it is far more artificial than those obtained in the case of the coloured fillers.

The second parameter which had to be tested was the gloss of the samples. Gloss measurements were obtained using the Neurtek Reflectometer mod. RB, with a measuring geometry of 20°, 60° and 85° (Fig. 2). A similar measurement methodology has proven successful in the gloss measurement of painting samples [6, 7]. In this case, 60° geometry was selected [8], with a 5x6cm measurement area.

COLOURED FILLER

STUCCO + RETOUCHING

Table 1. Attributes of tested retouching materials. (A: Affordable/ NA: Not Affordable)

204

Wet-on-wet application

Similar texture to the original

TS-WAT

TRADITIONAL STUCCO + WATERCOLOUR

NA

NA

TS-PVA

TRADITIONAL STUCCO + PVA INPAINTING MEDIUM

NA

NA

TS-GAMB

TRADITIONAL STUCCO + GAMBLIN

NA

NA

TS-GO

TRADITIONAL STUCCO + GOUACHE

A

NA

MOD

PIGMENTED MODOSTUC

A

A

BEVA

PIGMENTED BEVA GESSO

A

A

MOW

PIGMENTED MOWILITH DMC FILLER

A

A


XXI. Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

3. RESULTS and Discussion Gloss measurement values were obtained using the aforementioned reflectometer (table 2). Four different measurements were taken on each surface and the average deviation was calculated from the numeric average of the absolute deviations of the series measurement using the following equation:

Figure 2. Sample preparation (above) for the filling on Urban Nomad 66. Gloss measurements (below) on the filling and retouching samples. © Silvia García FernándezVilla.

The measurements obtained show that Gustav Berger’s PVA inpainting Medium and Mowilith® DMC Filler have a more satin or semi-glossy finish, as they have values of 5.8±0.84 and 2.6±0.04, respectively. These values are far higher than the value of the original painted area, which had a value of 0.7±0.05. According to their gloss values, the most appropriate materials are traditional stucco with a Gamblin Conservation Colours retouching layer, pigmented Modostuc® and pigmented Beva Gesso®.

Table 2. Gloss values of tested retouching and filling materials (60 degrees) Gloss values at 60 degrees

ORIG

SURROUNDING PAINTING LAYER

Average

A

B

C

D

± Deviation

0.7

0.6

0.7

0.8

0.7±0.05

STUCCO + RETOUCHING LAYER TS-WAT

TRADITIONAL STUCCO + WATERCOLOUR

1.2

1.5

1.3

1.5

1.4±0.13

TS-PVA

TRADITIONAL STUCCO + PVA INPAINTING MEDIUM

6.5

6.6

4.5

5.7

5.8±0.84

TS-GAMB

TRADITIONAL STUCCO + GAMBLIN

0.7

0.7

0.7

0.8

0.7±0.04

TS-GO

TRADITIONAL STUCCO + GOUACHE

0.9

0.8

0.9

0.9

0.9±0.04

COLOURED FILLER MOD

PIGMENTED MODOSTUC

0.7

0.7

0.8

0.7

0.7±0.04

BEVA

PIGMENTED BEVA GESSO

0.7

0.6

0.6

0.7

0.7±0.05

MOW

PIGMENTED MOWILITH DMC FILLER

2.7

2.6

2.6

2.6

2.6±0.04

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

205


XXI. Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

After evaluating the attributes of the tested retouching materials and their gloss values, the most suitable materials are pigmented Beva Gesso® and pigmented Modostuc®, as they are able to provide the required wet-on-wet application, high colour saturation, impasto texture and matte finish.

Figure 3. Detail of one of the paintings before (above) and after retouching with coloured Beva Gesso® (below). © Silvia García Fernández-Villa.

Retouching was therefore completed using both materials on the treated paintings. An isolating layer made up of an acrylic resin based on Butyl Methacrylate (Degalan® P550) in benzene (15%) was first applied in the areas with losses. The coloured filling was then applied to all the treated paintings with excellent results (Figs. 3 and 4). Only minor chromatic adjustments using watercolour were required in some areas

206

in order to complete their visual and chromatic reintegration. Varnishing the filling area is not recommended in the case of the coloured fillings used, as this has a critical impact on their saturation and lightness.

Figure 4. Detail of the retouching process of the painting Urban Nomad (1979) with coloured Modostuc® filler: before treatment (above), during the retouching process (centre) and after (below). © Silvia García Fernández-Villa.

4. CONCLusions Coloured synthetic fillers are an interesting alternative to traditional two-component retouching layers (stucco and colour retouching) in the case of paint loss areas with


XXI. Filling as retouching: the use of coloured fillers - in THE retouching of contemporary matte paintings

high colour saturation, large impastos and a matte finish. In the case of the treated paintings, twocomponent retouching layers and several coloured fillers were tested to evaluate their aesthetic attributes and shine. According to their gloss values, the most appropriate were traditional stucco with Gamblin Conservation Colours retouching layer, pigmented Modostuc® or pigmented Beva Gesso®. In this case, retouching with pigmented Modostuc and pigmented Beva Gesso® were selected, producing excellent results on the treated paintings as they also provide the required wet-on-wet application, high colour saturation, impasto texture and matte finish. The disadvantage of these coloured fillers is the high colour change that occurred during the drying process. For this reason, during the retouching, samples of coloured filling should be compared to the original paint area when they are dry, not just wet. Finally, varnishing the retouched area is not recommended, as this would have a critical impact on its lightness and saturation.

REFERences [1] SCICOLONE, Giovanna C.; Il restauro dei dipinti contemporanei. Dalle tecniche di intervento tradizionali alle metodologie innovative. Firenze: Nardini Editore, 1993. [2] Bailão, Ana: Application of a methodology for retouching ,  CeROArt (2010). Available at: http:// ceroart.revues.org/1603 [9 December 2015]. [3] Padorno, M. in Manuel Padorno. Nómada urbano (Catál.). Las Palmas de Gran Canaria: Museo Casa Colón, 1981. [4 Castro Borrego, Fernando: Manuel Padorno: la mirada arborescente. Islas Canarias: Viceconsejería de Cultura y Deportes, Gobierno de Canarias, 1994, pp. 85. [5] WESTERDAHL, Eduardo: Reflexión sobre la reflexión del pintor Padorno, in Manuel Padorno. Nómada urbano (catál.). Santa Cruz de Tenerife: Galería Leyendecker, 1982. [6] García Fernández-Villa, Silvia; López, María; De la Roja, José M.; San Andrés, Margarita. Evaluación de sistemas de limpieza en seco sobre pinturas mates contemporáneas. In Actas 15ª Jornadas de Conservación de Arte Contemporáneo. Madrid: Museo Nacional Centro de Arte Reina Sofía, 2015, pp.137-150. [7] De la Roja, José M.; Santos, Sonia; García FernándezVilla, Silvia; San Andrés, Margarita.Efectos del barniz sobre el color de las reintegraciones cromáticas. In Actas X Congreso Nacional del Color.Valencia, 2013, pp. [8] ISO (International Standarization Organization), Norma 2813:1999 Pinturas y barnices – Determinación del brillo especular de películas de pintura no metálicas a 20°, 60° y 85°, 1999.

Acknowledgements This study was funded by the Community of Madrid under the GEOMATERIALS 2 project (S2013/ MIT-2914) and by Projects 185/2014, 85/2015 and 188/2015 signed with the Cultural Association Manuel Padorno. Author is also  grateful to the  Materials Laboratory  at the Painting and Restoration Department of the UCM [Lab 397 of the RedLab Community of Madrid].

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

207


208


XXII

STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS


XXII.

STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS

Theochari Angeliki (1), Christou Vasiliki (2)

(1) Email: angelikudi@gmail.com

(2) Email: christouvasiliki@hotmail.com

ABSTRACT Most exterior decorations have shown damage. The structure of wall paintings is complicated, and the causes of damage are many and varied. This study analyses the materials and the techniques which were used in the exterior paint decoration of the Academy of Athens. It investigates the types of damage, preservation environment, and previous conservation treatments and develops the implemented treatment. The decoration depicts symbols and motifs of two deities (Apollo and Athens) and is extended around the building, at the top of the marble walls. It took a long time of research, many tests, daily contact with the paint decoration and use of specialized scientific equipment to collect the necessary information and data. A conservation project was undertaken.

Keywords Conservation; Retouching; Documentation; Pigments; Marble; Polychrome.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

211


XXII. STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS

1. INTRODUCTION The planned research addresses the need of documentation of works of art that standing outdoors, endangered by the environmental impact. The purpose of this talk is to present our approach and methodology, and to elicit input and discussion. We have done the same with many professionals involved in the conservation of outdoor sculpture and ornamentations.

water, has been linked to detrimental corrosion on marbles and painting layers [4]. Taking into consideration the corrosion factors, the historical significance that monument has, and the wealth of its painted decoration, we motivated on writing this study. The ultimate goal of this research is to mention the important role of maintenance and to document all the necessary information about the monument from the beginning of its creation.

Marble remains one of the most common stones in outdoor sculpture. On a national scale, outdoor marble monuments in Greece number in the tens of thousands [1]. Most of them bring painting decoration known as polychrome. Academy’s outer decoration is only a portion, but also very significant, of marble sculpture and polychrome ornamentation which require preservation. The Academy of Athens is a paragon neoclassical construction in the modern city of Athens. The building was designed as part of an architectural “trilogy” in 1859 by the Danish architect Theophil Hansen, along with the University and the National Library [2]. Its polychrome and the inspiration for the paintings originate from the polychrome of Greek classical times, [3]. The exterior painted decoration extends around the building, at the top of the marble walls. It comes together as coloured, especially red and blue, and gilded layers in motifs like rosettes, meanders, rosettes and others. This monument is located in one of the crowded streets of the city centre, unsheltered and endangered by the current weather and city’s air pollution. The building of the Academy of Athens has been suffered dramatically from corrosion as a result of outdoor exposure. Increasing pollution in our environment, especially acid rain or condensed 212

Figure 1. Remaining traces of the initial decoration.

2. MATERIALS AND METHODS In order to report the maintenance status of the external paint decoration of the Academy Of Athens, the materials and methods of its construction were studied. Through this study it was established that the initially pigments were not survived and that the samples which we observed were from the first conservation attempt of the monument.


XXII. STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS

2.1. Research

Firstly, was conducted a comprehensive survey on the making of the painted decoration on the outside part of Athens Academy. We mainly based on the records of the Academy of Athens, in testimonies of various technicians and conservators who worked periodically at the monument and on the first drafts of Hansen, which were found. Collecting all the necessary information from our sources and comparing them with the current state of the decoration we confirmed the fact that the original paintings didn’t managed to survive through the years, mainly due to external factors and the pathogenesis of the monument (weather, pollution, materials failure) and that the remains found in marbles of Athens Academy is the result of the first monument restoration process.

2.2. Stages of the External Paint Layer

The first stage accounts for the primarily painted decoration in years between 1875 and 1882. However, the colours remained for seventy years. After this duration the loss was almost total, however remaining traces of the original decoration (Fig. 1) made a reproduction possible. The second stage was a polychrome repainting (Fig. 2) that was performed by a painter, Mr Samartzi, as a first attempt of restoration, during 1980-1990. Unfortunately no interventions records are existed, only general descriptions. Therefore we are missing specific details such as exact dates of when exactly he worked, in which parts, what materials had been used and when it was completed. The records only

reviled that the repainting was made from the existing tracks of the original painting layer.

2.3. Pigments, Gildings and Applied Methods

Figure 2. First repainting intervention.

As far as materials and the methods of the initial paint layer’s creation is concerned, no records survived. It is only supposed that ancient techniques such as gilding and encaustic were used. Regarding the repainted stage, an analysis to the maintained pigments were conducted with the use of Raman spectroscopic technique. This technique is used to observe vibrational, rotational, and other low-frequency modes in a system.  Raman spectroscopy is commonly used in chemistry to provide a fingerprint in order to identify molecules. In our case Ramman helped to provide the necessary knowledge about constitutive materials of the design. The board below provide the pigments of the coating colours as identified by Raman analysis (Table 1):

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

213


XXII. STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS

Table 1. Pigments of the coating colours as identified by Raman analysis. Sample 1

Raw Siena

Sample 2

Ocher

Sample 3

Brown Umber

Sample 4

Cobalt Blue

Sample 5

Cadmium Red

Sample 6

Cerulean

Sample 7

Black

3.1. State of preservation

The painting structure was of generally good condition and showed partly some serious problems. The marble support is in stable condition, although numerous and scattered areas of loss and disruption were seen. Major fractures extended to the overlying layers, a large network crackle pattern was observed in the surface (Fig.3).

The application of those pigments were directly to the marble without an intermediate layer. The gilding procedure was firstly to clean the marble surface in order to be as smooth as possible. By completing this preparation, the surface was covered by two different colour layers of enamel paint (a mixture Alkyd Undercoat and Duco). The material (miction 24 hours) was applied with a brush∙ afterwards placed 22 carts gold leaf. Finally to protect the repainting a mat varnish was used.

3. RESULTS AND DISCUSSION The survey about the materials lasted almost one year and showed that the works for the maintenance of the Academy of Athens doesn’t stop indefinitely, as it continues to be exposed to weathering and corrosion factors. Subsequently, a continuous observation by conservators is needed as long as a timeless maintenance in order to secure the artworks and the construction in total.

214

Figure 3. Cracks in detail.

The paint layer exhibited extensive flaking and losses, as well as the gold leaves. Some areas were quite faint and discolored, which suggested that light exposure, surface oxidation, or other environmental factors have contributed to the altered appearance of the pigments. A thick layer of soot and surface grime covered the surface. Because the painting was porous and unprotected, dirt had penetrated due to water seepage and had stained and disfigured the pigments (Fig.4).


XXII. STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS

Figure 4. Stained and disfigured pigments.

The best-preserved pigments were on the masonry which is protected from the cornice moldings, gables and ceiling. The worstpreserved was the upper part which accepts more intense sunlight and water seepage. The painted surface tented to disappear in these areas. Also, the original appearance of the painting had been altered by the subsequent restoration, and deterioration of original and restoration materials.

pigments (Raw Siena, Ocher, Brown Umber, Cobalt Blue, Cadmium Red, Cerulean, Black) that Raman spectroscopic had indicated. Pigments had the form of powder and the acrylic emulsion Primal was used as a binder medium. For the gildings, gold leaves 22K were applied and a special glue layer called mixtion -3hours drying time. By the end of the above, inpainting and gildings were coated with a transparent protective lacquer Primal SF016 20%. Treatment of the decoration stabilized its condition and made it more cohesive Materials used were reversible whenever possible, and applications were kept to a minimum. The paintings are clear, intact, colorful, and beautiful (Fig. 5).

3.2. Restoration and retouching

Because of the conditions described here, the decoration was not considered stable. In this stage a scientific restoration and retouching that took place in 2004 by the scientific company “Aeinaes�. The basic plan of treatment included removal of the soot and surface grime, stabilization of the fragile painting layer and gold leaf, and retouching. Also, this treatment included removal of arbitrary previous innervations, where failures appeared, and inhibition of deleterious factors. The new paint layer was applied directly on the clear marble surface and executed with the

Figure 5. Painted and gilded decoration, after treatment.

4. CONCLUSIONs Aiming to fulfill the aim of this research, a qualified and updated archive was created. It contains historical data, all materials and their components, an integrated recording of the painting layers and their condition, accompanied with large photographic content.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

215


XXII. STUDY OF TECHNOLOGY AND CONDITION SURVEY OF PIGMENTS OF MARBLE ELEMENTS ON THE ACADEMY OF ATHENS

The archive was created with consideration of the necessities of the conservation and the restoration field while respecting the historical value and cultural aspect of the monument. This survey was necessary to report all these consecutive conservation works that took place in the polychrome decoration of the Academy of Athens during the centuries. This research will be useful also in the future, while the monument is exposed to weathering and corrosion factors and a future investigation and treatment is inevitable. In general, proper and systematic record preserves the knowledge of previous interventions, which are an integral part of artwork’s history .Such documentation is a useful tool for both scientists and for ordinary art lovers.

216

REFERENCES [1] WRINKLER, E M. - Weathering of crystalline marble, The engineering geology of ancient works, Monuments and historical sites. Athens, 1988. [2] ZANTEN, David - The architectural polychromy of the 1830’s. Garland Publishing, 1970. [3] CHRISTIANSEN, J.- The rediscovery of Greece. Denmark and Greece in the 19th century. Ny Carlsberg Glyptotek, 2000. [4] LABROPOULOS, Vasileios - Academy of Athens: conservation and maintenance study. Athens, 2002. [6] RALPH, Mayer. - The Artist’s Handbook of Materials and Techniques: Fifth Edition, Revised and Updated. New York: Viking adult, 1991. [5] PAPPAS; John - Restoration of decorative painting of the Academy. Of Athens, Session on 28th February, Proceedings of the Academy, 1985,pp. 220-226.


XXIII

PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS


XXIII.

PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS

Maria Cristina Coelho Duarte (Cristina Coelho) (1) Débora dos Santos Lopes (Débora Lopes) (2)

(1) Oficina Escola de Manguinhos; Postal address: av. Brasil, 4365, Manguinhos, CEP: 21040-900, Rio de Janeiro/RJ - Brasil; E-mail address: cristinacoelho@ fiocruz.br; lopes.debora@gmail.com

Abstract This article presents the “Course of craftsmen in painting’s conservation and restoration in historic buildings”, carried out at Oficina Escola de Manguinhos (OEM) in 2013/2014: an example of the importance of craftsmen’s instruction in restoration and in the improvement of the quality of the interventions. The focus of the presentation is color retouching, and the approach will focus on the pedagogic project, which aims the transmission of knowledge – both specific and global, concerning the field of preservation- and the development of the necessary abilities to carry out the professional practice. The OEM integrates the Núcleo de Educação Patrimonial (NEP) of Departamento de Patrimônio Histórico (DPH) of Casa de Oswaldo Cruz (COC), and aims to instruct people to practice the conservation and the restoration crafts of the constructive and artistic elements of architectural heritage, and to contribute to the preservation of Fundação Oswaldo Cruz (Fiocruz) collection. This foundation was created in 1900 in the North Zone of the city of Rio de Janeiro, with the objective of eradicating the bubonic plague that assailed the Rio’s population in the turn of the 20th century. Since then, it has been developing research and producing vaccines and drugs aiming the promotion of public health, while at the same time it has been promoting and building many scientific and cultural collections.

Keywords Chromatic reintegration; Painting; Pigments; Course of craftsmen; Conservation; Restoration.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

219


XXIII. PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS

1. INTRODUCTION This article will look at the “Auxiliary course in conservation and restoration of paintings in historic buildings”, held at the Oficina Escola de Manguinhos (OEM) in 2012 and 2013. This course helped to demonstrate the importance of the education and training of craftsmen to work on the conservation and restoration of heritage buildings and their contents, by improving the quality of interventions in this field. The presentation is focused on pictorial restoration and on the approaches used in the teaching and transmission of knowledge and skills - specific and general - in the field of preservation. It also looks at the methods used for the development and practice of relevant skills; at the real experiences provided by the course and demonstrates its success through evaluation of the graduates progress on completion of the course. Before going into detail about the course itself, I will give a little background about its origin.

1.1. Oficina Escola de Manguinhos (OEM)

The OEM (figure 1) integrates Núcleo de Educação Patrimonial (NEP) of the Departamento de Patrimônio Histórico (DPH) of the Casa de Oswaldo Cruz (COC). Its aim is to educate and train craftsmen in conservation and restoration of historic buildings.

220

Escola de Manguinhos. Figure 1. Logo Oficina 1.2. Fundação Oswaldo Cruz

Fiocruz is an institution of the Brazilian Ministry of Health, created in1900 in the north zone of the city of Rio de Janeiro, Brazil (figure 2), in order to eradicate the plague that affected the Brazilian population at the turn of the nineteenth to the twentieth century. Since that time it has focused on developing and producing vaccines and medicines aimed at improving public health and the general quality of life of the population, through an expanded concept of health.

1.3. Casa de Oswaldo Cruz

During the same period, Fiocruz created several cultural and scientific archives. Since the 1980s, these archives have been the focus of the mission of Casa de Oswaldo Cruz (COC). The unit established at this time for the purpose of historical research about the institution, the sciences and public health in Brazil, as well as the preservation of such archives and disclosure of the information there in.


XXIII. PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS

commitment and external compromises which might affect their reliability and dedication.

Figure 2. Historic buildings of Fiocruz in Manguinhos, Rio de Janeiro/RJ-BR. Collection COC/Fiocruz.

1.4. Details of courses offered by the Oficina Escola de Manguinhos

The OEM offers courses for both internal and external public. The internal public is composed by professionals working within our organization on the conservation and restoration of the historic buildings of Fiocruz. The external public is composed by aged 18 and above, with a minimum education equivalent to the first years of complete basic formal education (1st to 4th years in Brazil), giving priority to those with some practical experience in civil construction. The OEM does not have a regular structure within their courses with regards to the workload and hours required for completion, or in relation to the crafts and techniques taught, and is also without a permanent staff team. Each course is designed and customized, depending on the techniques required and professionals available. All courses are free. For this reason the selection process is based on the requirements of each course, with criteria which takes into account the applicant’s aptitude for the techniques to be taught (figure 3), as well as to their personal

Figure 3. candidates performing test specific skills during the selection process for admission to the course.

2. THE

AUXILIARY COURSE IN CONSERVATION AND RESTORATION OF PAINTINGS IN HISTORIC BUILDINGS / OFICINA ESCOLA DE MANGUINHOS (2012 to 2013)

The course objective was based on traditional and modern painting techniques (decorative or not) and their forms of conservation and restoration. An approach that went well beyond the mere transmission of knowledge and development of specific skills. The course also sought to give the student an insight into the specialist world of restoration and preservation of cultural artifacts; to promote general concepts and principles of preservation; to provide concrete experiences of conservation and restoration and their contexts, seeking to stimulate criticism and debate in the field of preservation for professional ethics and consciousness.

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

221


XXIII. PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS

Consisting of 204 hours of study, the course was structured in modules, following the methodology adopted and improved since the creation of OEM, as follows:

2.1. Basic module - 56hours

Composed of disciplines for the of basic knowledge necessary for in conservation and restoration buildings, also addressed ethical the market in general:

acquisition application of historic issues and

2.1.1. Principles of preservation of cultural heritage (Cristina Coelho - Departamento de Patrimônio Histórico / COC / Fiocruz)

The discipline aims to give the student the ability to understand the importance of, as well as the context for preservation, and for them to work conscientiously and responsibly within their professional scope. For them to have an awakening of the sense of belonging and identity in the construction of citizenship, through an introductory knowledge of cultural property, the basic principles of preservation of cultural heritage, and of the theoretical concepts of architectural conservation. 2.1.2. Architectural survey (Bruno Sá - Departamento de Patrimônio Histórico/ COC / Fiocruz)

The discipline aims to enable the student to be able to: make measurements and represent, in the form of sketches, the measured elements and the verified damage to them, using the basic knowledge of the techniques and forms of representation of architectural elements and of common damage; understand graphic surveys, architectural projects and mapping

222

of architectural damage, especially of painted surfaces. 2.1.3. Architecture in Brazil (Inês Andrade - Departamento de Patrimônio Histórico/ COC / Fiocruz)

The discipline aims to enable the student to: be able to understand the main features of, and recognize copies of different styles of Brazilian architecture (especially from Rio de Janeiro), place them in historical time, from their basic knowledge of corresponding historical periods and architectural styles as seen in Brazil. 2.1.4. Health and Safety at work (Roberto Azevedo - Instituto de Pesquisa Clínica Evandro Chagas / Fiocruz)

The discipline aimed to enable the student to act responsibly within the work environment, and while carrying out their conservation and architectural restoration work, prevent accidents and injury to the people entering the site, through a basic knowledge and implementation of the basic legislation and the use of different types of Personal Protective Equipment (PPE) and Collective Protection Equipment (CPE). 2.1.5. Traditional materials and construction systems (Daniel Moreira - Departamento de Patrimônio Histórico/ COC / Fiocruz)

The discipline aimed at enabling the student to be able to chronologically interpret a building, and identify constructive changes using their basic knowledge of materials and traditional Brazilian construction systems, and the evolution of their application in architecture; an interface between the disciplines of architecture in Brazil and Architectural Surveys.


XXIII. PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS

2.2. Specific module - 102 hours:

2.2.2. Introduction to conservation techniques

The Specific Module consisted of theory and practice aimed at developing specific skills for execution in the conservation and restoration of paintings in historic buildings. Classes for this module were due to take place in the workshop at the Manguinhos School and Chapel of the UFRJ University Palace, in Urca / Rio de Janeiro, which sadly suffered a fire shortly before the completion of the course and awaited resources for restoration work to begin. This was subsequently possible due to a partnership between the COC and theDivisão de Preservação de Imóveis Tombados of theUniversidade Federal do Rio de Janeiro (DIPRIT / UFRJ).

(Deborah Lopes - Departamento de Patrimônio Histórico/ COC / Fiocruz)

2.2.1. Introduction to tradecrafts (Deborah Lopes - Departamento de Patrimônio Histórico / COC / Fiocruz)

The discipline aimed to enable the student to develop appropriate skills for use in conservation services and restoration of paintings in historic buildings, using their knowledge of traditional construction processes, especially with paintings in different media and of different types. The menu of disciplines encompassed the instruments and their practical uses for painting in traditional buildings; ways to care for and package materials, tools, equipment and products (Figure 4); the preparation of different surfaces for painting; color theory and types of pigments; introduction to traditional painting techniques (Figure 5); introduction to contemporary painting techniques; and material compatibility.

The module on traditional building materials and systems aimed to allow the student to be able to perform hygiene procedures, consolidation, recovery, finish and protection of works, conservation services and architectural restoration, under the guidance of restorative professional, using their knowledge of conservation and restoration techniques. The menu of disciplines encompassed introduction to pathology and execution of mapping damage; prospection - the importance of, techniques and care of implementation, and ways of packaging samples and / or collected fragments; diagnosis of the conservation status; intervention criteria; introduction to conservation techniques; consolidations; sanitization / disinfection; fixations of remaining paint layers; introduction to restoration (removals; stripping, reintegration); and finishes / protections. 2.2.3. Introduction to the fresco technique workshop (Leila dos Santos - Jequitibá Restauro)

The workshop aimed to give the student basic knowledge about this art and technique - its history, major works undertaken and technical procedures for their implementation, how to protect them during the cleaning procedures, consolidation and pictorial reintegration.

2.3. Complementary Module - 46 hours:

The complementary module comprised of: Lectures by guest professionals: Fiocruz technicians, cultural heritage preservation agencies and professionals in the field of

III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015 Postprints rech3

223


XXIII. PICTORIAL RESTORATION- THE TRAINING OF CRAFTSMEN, AT THE OFICINA ESCOLA DE MANGUINHOS

conservation and restoration of paintings, to present interventions and experiences.

which included three combined stages, namely:

Visits to restoration sites, restored buildings and urban complexes.

• Step 1: Expository class on color theory, with analytical work on the color compositions present in photos and paintings from different periods presented to the students and practical exercises aimed at decoding the color palettes used in these paintings..

This module aimed to present and illustrate the preservation of the cultural property fieldwork (collections and experiences) with the aim of presenting themes that permeate the world of conservation and architectural restoration, in particular of paintings, with concepts, principles and experiences of conservation and restoration; aspects related to the labor market of conservation and restoration; and the legal requirements among other things.

3. THE

SPECIFIC MODULE ON THE TEACHING OF REINTEGRATION

FOCUSING PICTORIAL

Reintegration techniques covered in the course were pointillism, the trattegio, absence and imitative, from the following methodology: a) the exhibition of renowned works of pictorial reintegration and others that have been questioned from the perspective of conservation in the national and international levels; b) the exercise of criticism about the action to reintegrate and the choice of technique for each case from a historical background, their environmental and cultural contexts and the concepts established by the preservation organisms, and c) the practice of the techniques covered on paper and wood substrates (figure 6). Reintegration techniques have been taught in the course from the following methodology,

224

• Step 2: Demonstration of reintegration techniques suggested in the course (pointillism, the tratteggio and imitative) followed of practice by the students who underwent to two batteries of simple exercises on paper. The first consisted on filling with a predefined color, small squares of 4x4 cm, with the above techniques. Second, it was necessary to obtain specific colors from the superposition of other colors. • Step 3: from the reproduction of wood glued on paintings, and purposely damaged with loopholes, it was up to the student a) assess the need and/ or the possibility of reintegration and b) the use of each of the techniques studied where they identified the need and the possibility of reintegration.

Finally, each student was able to compose a kind of technical exercise book with all the techniques learned.


4. DEVELOPMENTS / EXPECTATIONS Student participation was consistent throughout the course with high levels of dedication demonstrated. There were no dropouts from the course and the results were very satisfactory with regard to student achievement concerning the subject knowledge and skills needed for conservation practices and restoration of paintings. On completion of the course, some graduates found job opportunities in the field of restoration. Others, who already worked in the area, improved their practices and gained new opportunities. Some graduates, who chose to do the course out of a personal interest in the subject, although not active in the field, reported that the experience gained on the course, brought a new understanding and appreciation about cultural heritage and the need for its preservation.


III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE 2015

Postprints rech3


III INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE

Postprints . 2015

Postprints rech3  

01

Read more
Read more
Similar to
Popular now
Just for you