POSTPRINTS_RECH_4_CROATIA_4_TH_INTERNATI

ACADEMY OF ARTS, UNIVERSITY OF SPLIT 20th | 21st OCTOBER 2017 POSTPRINTS RECH 4 | CROATIA 4TH INTERNATIONAL MEETING ON RETOUCHING OF CULTURAL HERITAGE, RECH 4

2 4th International Meeting on Retouching of Cultural Heritage, RECH4 Host Venue | Academy of Arts, University of Split Title | POSTPRINTS RECH4 CROATIA Editorial Coordinators | Ana Bailão, Sandra Sustic Graphic Design | INEDITAR | Cristina Dordio Abstracts Proofreading | Graham McMaster Venue and Date | Split, Croatia, 2017 ISBN | 978-953-6617-42-5 Organizing Commitees Support

3 The Organizing Committee would like to acknowledge the contribution of the the contribution of the members of the Advisory and Scientific Committees who made the selection of the communications and posters for the Meeting. We gratefully acknowledge the financial support and sponsorship of the Ministry of Science and Education of Croatia, the Ministry of Culture of the Republic of Croatia, the University of Split and the Split Student Centre. Special thanks goes to the Tourist board of Split, the City Museum of Split and the City of Split for their support in organising the social program of the Meeting. We express our gratitude to Split University Library and the Faculty of Chemical Engineering and Technology for enabling us with the conference venue. We would also like to thank the Split Department for Conservation for providing us with the workshop materials. Special thanks goes to RETES.HR print centre and OPG Mateo Curić. We also express our gratitude to Gabriela Rocha and FabLab Lisboa (Portugal) and to Escola Artística e Profissional Árvore (Porto, Portugal) for providing us with the conference badges. ACKNOWLEDGEMENTS

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5 COMMITTEES ADVISORY COMMITTEE Visnja Bralic | Croatian Conservation Institute, Zagreb, Croatia Sagita Mirjam Sunara | Arts Academy of the University of Split, Croatia ORGANIZING COMMITTEE (alphabetical order) Ana Bailão | CIEBA/ University of Lisbon | Catholic Portuguese University/ CITAR, Portugal Ana Bidarra | Cinábrio, Conservação e Restauro | GeoBioTec Research Centre, Aveiro University, Portugal Francisco Silva | Árvore | Escola Artística e Profissional Árvore, Portugal Frederico Henriques | Catholic Portuguese University/ CITAR, Portugal LOCAL ORGANIZING COMMITTEE (alphabetical order) Jurica Matijevic | Arts Academy of the University of Split, Croatia Lana Kekez | Arts Academy of the University of Split, Croatia Sagita Mirjam Sunara | Arts Academy of the University of Split, Croatia Sandra Sústic | Arts Academy of the University of Split, Croatia Tina Tomsic | Arts Academy of the University of Split, Croatia TECHNICAL COMMITTEE Krešimir Bosnić | Arts Academy of the University of Split, Croatia Nikola Radošević | Arts Academy of the University of Split, Croatia Stjepan Krešić | Arts Academy of the University of Split, Croatia Bernarda Đurić | Arts Academy of the University of Split, Croatia Mateo Curić | Freelancer, Croatia Josip Pašalić | Arts Academy of the University of Split, Croatia Nikolina Drlje | Arts Academy of the University of Split, Croatia Silvija Matas | Arts Academy of the University of Split, Croatia Katarina Strinić | Arts Academy of the University of Split, Croatia Marija Curić | Arts Academy of the University of Split, Croatia Lucija Jolić | Arts Academy of the University of Split, Croatia

6 SCIENTIFIC COMMITTEE (alphabetical order) Ana Bailão | CIEBA/ University of Lisbon | Catholic Portuguese University/ CITAR, Portugal Ana Bidarra | Cinábrio, Conservação e Restauro | GeoBioTec Research Centre, Aveiro, Univ., Portugal Ana Calvo | Complutense University, Madrid, Spain Agnès Le Gac | FCT - New University of Lisbon/LIBPhys-UNL, Portugal Ana Martins | Museum of Modern Art, MoMa, New York, USA Arianne Vanrell | Museo Nacional Centro Reina Sofía, Madrid, Spain Alicia Sanchez Ortiz | Complutense University, Madrid, Spain Alice Nogueira Alves | Fine Arts Faculty of the University of Lisbon/CIEBA, ARTIS, Portugal Antonino Cosentino | Cultural Heritage Science Open Source, Italy Barbka Gosar Hirci | Institute for the Protection of Cultural Heritage of Slovenia Branko Pavazza | Croatian Conservation Institute, Croatia Cristina Montagner | Centre of Physics, Campus de Gualtar, University of Minho, Braga, Portugal Emmanuelle Mercier | Institut Royal du Patrimoine Artistique, Bruxelles, Belgium Estelle De Groote | Institut Royal du Patrimoine Artistique, Bruxelles, Belgium Élia Roldão | Universidade NOVA de Lisboa, Caparica, Portugal Francesca Tonini | Ca´Foscari University in Venice | University of Urbino, Italy Fernando Costa | Polytechnic Institute of Tomar, Portugal Frederico Henriques | Catholic Portuguese University/ CITAR, Portugal Helena Melo | Évora University/HERCULES Lab/Évora University, Portugal Isabel Argerich | InstItuto del Patrimonio Cultural de España, Madrid, Spain Isabel Tissot | Archeofactu & LIBPhys-UNL, Portugal Ilaria Saccani | CESMAR7, Italy José Manuel de la Roja | Complutense University, Madrid, Spain Laura Fuster-López | Polytechnic University of Valencia, Spain Leonor Loureiro | Polytechnic Institute of Tomar, Portugal Lorraine Mailho | C2RMF, France Luís Pereira | Água de Cal - Conservação e Restauro, Portugal Lucija Močnik Ramovš | University of Ljubljana, Slovenia Mara Kolic Pustic | Croatian Conservation Institute, Croatia Ricardo Triães | Polytechnic Institute of Tomar, Portugal Rocío Bruquetas | Museo de América, Spain Rui Bordalo | Évora University/HERCULES Lab/Évora University, Portugal Rubén Morales | Complutense University, Madrid, Spain Silvia García Fernández-Villa | Complutense University, Madrid, Spain Sandra Sústic | Arts Academy of the University of Split, Croatia Stefano Scarpelli | Private conservation-restoration studio, Florence

7 Alba Guerrero Amparo Escolano Mena Ana Bailão Ana Bidarra Ana Carolina Rodrigues Ferreira Ana Oblak Anita Klančar Kavčič Antonija Gluhan Bakonyi Tímea Beatriz Doménech García Eve Bouyer Branko Pavazza Brian Baade Clara M. Prieto Dorotea Krstić Nancy von Breska Ficovic Emmanuelle Mercier Erika Rabelo Filip Adrian Petcu Francesca Tonini Frederico Henriques Gabor Erdei Ivana Letilović Julija Baćak Jure Matijević Katarina Alamat Kusijanovic Katarina Tomaš Kristin deGhetaldi Kristina Krivec Lana Kekez Leonardo Severini Leonor Loureiro Liliana Querido Cardeira Maja Sučević Miklin Mara Kolić Pustić Marisol Valenzuela Martina Bagatin Martina Lesar Kikelj Martina Vuga Mladen culic Paolo Roma Pedro Antunes Rosa Senserrich-Espuñes Ruben Morales Sagita Mirjam Sunara Sandra Šustić Sanela Huzjak Sara Aničić Eterović Serena Francone Simona Pannuzi Simona Škorja Stefano Scarpelli Tina Tomšić Vanessa Ubaldi Visnja Bralic REGISTERED AUTHORS ÍNDEX

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9 The retouching process is one of the last steps of a conservation and restoration intervention. Expectations are normally high and conservators are continuously challenged to acquire innovative techniques and new materials to satisfy this need. One important part of retouching is to use and incorporate materials with long-term durability, but always based on the concept of minimal intervention. The accomplishment of these expectations entails a detailed diagnosis and planning of the treatment with attention to function, to aesthetics and to the stability of the materials. Communication is the key word for a good intervention. Proper communication will not only enhance the conservator– owner relationship but also provide greater acceptance of the treatment planning. The evolution of digital technology has created exciting opportunities for improving this communication process and to facilitate a smooth workflow, from diagnosis to the final treatment and maintenance phase. The International Meetings on Retouching of Cultural Heritage (RECH), initiated in 2013, have gained an international audience, bringing together conservation-restoration professionals, academic members, students and independent researchers from across the world. The conferences aim to promote the exchange of ideas, concepts, terminology, methods, techniques and materials applied during the retouching process in different areas of conservation. This postprints presents the articles of the fourth edition of RECH that took place in Split (Croatia) from October 20th to October 21st, 2017 and was jointly organised by members of the Escola Artística e Profissional Árvore, the Faculty of Fine Arts of the University of Lisbon, the Arts Academy of the University in Split, the Catholic University of Portugal, the Cinábrio and University of Aveiro. The Scientific Committee, consisting of renowned experts FOREWORD

10 in the conservation-restoration field, selected 24 abstracts for communications and 16 abstracts for poster sessions, not all publish here. The titles cover a wide range of topics - from digital options for documentation, diagnosis and treatment, to new solutions and materials for filling and retouching of losses. The organizers give their thanks to all the members of the RECH Committees for their diligent work in setting up the programme and to the sponsors for their generous support. Ana Bailão on behalf of the Organizing Committee Sandra Šustić on behalf of the Local Organizing Committee

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13 An opportunity to reflect on differentiated retouching techniques used in Italy: methods and materials. Problem solving in a private practice context. Leonardo Severini The bad reputation of neutral retouching Eve Bouyer Baroque Master Mattia Preti and his workshop: two series of four evangelists from Dubrovnik Maja Kolić Pustić, Carlo Galliano Lalli, Nancy von Breska Ficović “All Saints are in the detail“: Retouching of a painting by Girolamo da Santa Croce Katarina Alamat Kusjanović; Sandra Šustić The suitability of powdered micro-cellulose for its use in paper conservation Rita Udina, Amparo Escolano The use of Aquazol® 500 as a binder for retouching colours: analytical investigations and experiments Vanessa Ubaldi, Roberto Bestetti, Roberto Franchi, Emanuela Grifoni, Pier Paolo Lottici, Francesca Modugno, Richard Wolbers, Daphne De Luca PVAC Retouching Colors: a brief history and introduction to Goldens’s newly formulated PVA. Conservation Colors Kristin deGhetaldi, Brian Baade, Joyce Hill Stoner, Jim Hayes, Samantha Alderson Using watercolour markers in chromatic reintegration Liliana Cardeira, Ana Bailão, João Linhares, Sérgio Nascimento Filling and colour reintegration in a single step Martina Vuga Retouching methods on the albumen and coloddion photographic processes from the Croatian State Archives Martina Bagatin Dealing with unsuitable retouches: the steps toward successful reintegration Ana Oblak Use of coloured synthetic fillers: the case of St Nicolas, a Baroque painting by Fortunat Bergant Simona Škorja 22 28 38 46 56 66 80 88 98 106 112 120

14 Mapping lacunae for chromatic reintegration with computer graphics software Frederico Henriques, Ana Bailão, Rui Bordalo, Agnés Le Gac, Alexandre Gonçalves, Liliana Cardeira, Eduarda Vieira, António Candeias Gold and polychromy on stone: a proposal of retouching methodology that can apply on all tridimensional artworks Simona Pannuzi, Marisol Valenzuela, Daria Montemaggiori, Giorgia Galanti “The golden stain of time”: the inpainting of gildings on wooden sculpture Emmanuelle Mercier, Erika Benati Rabelo A case study on reconstruction of the faux marble paint layer on a baroque wooden tabernacle Maja S. Miklin Retouching approaches to artwork on paper in the laboratory for conservation and restoration at the Croatian State Archives. Retouching of a Watercolour Landscape and a Map of Zadar from the 19th Century Sanela Huzjak Approaches to the conservation treatment and chromatic reintegration on watercolours, charcoal drawings, and a lampshade handpainting Leonor Loureiro The photographic retouching as fundamental intervention Rubén Morales González 130 138 144 152 160 166 176

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17 Influence of lighting sources in the processes of colour reintegration Beatriz Doménech, Vicente Guerola Blay, María Castell Agustí Chromatic reintegration in late 19th century albumen prints: analysing and testing different methodologies in Calouste Gulbenkian´s albums Alba Guerrero Selective removal of layers in layered systems of retouching: research project in progress Sagita Mirjam Sunara, Dorotea Krstić Reconstructing of The Sappho painting towards a better understanding in retouching Marija Lena Bosković, Sandra Šustić The issue of metamerism in Mario Agrifoglio’s paintings. Identification of fluorescent pigments through raman spectroscopy to define a methodology for retouching Serena Francone, Silvia Bruni, Chiara Zaffino, Katia Galli, Vittoria Guglielmi, Maddalena Boscacci Retouching religious paintings – examples from private practice Lana Kekez, Kristina Krivec, Julija Baćak Calcium hydroxide nanoparticles for wall painting retouching. The chapel of Saint Michael in the Royal Monastery of Pedralbes, Barcelona Rosa Senserrich-Espuñes, Lidia Font-Pagès Retouching a double-sided 19th century processional flag-icon Filip Adrian Petcu Selecting methods for retouching a polychrome and gilded altarpiece with elements dating from different periods Sara Aničić Eterović, Ivana Letilović, Katarina Tomaš Mixing and matching. A survey of retouching materials Ana Bailão, Liliana Cardeira Fernando Mardel, a portuguese painter-restorer. Retrospective of his retouching work Carolina Rodrigues Ferreira, Fernando António Baptista Pereira, António Candeias, Mercês Lorena 188 194 200 206 212 218 226 232 244 248 256

18 The reconstruction of three strongly damaged panel paintings of a 16th century Sienese predella Ágnes Kuna, Tímea Bakonyi, Erdei Gábor Inpainting in Exhibition Clara M.Prieto 264 270

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Abstract Italy has made a specific choice in pictorial treatment of lacunas: Roman Vertical tratteggio and Florentine selezione cromatica. Both methods are based on the same approach avoiding deceptive retouching in favor of visible techniques to make losses recognizable at a close range of view. Currently in Italy we continue to carry out recognizable retouching on public paintings. Nowadays, however, the choice of intervention is made mostly by art historians who are responsible for and in charge of public conservation projects, so restorers run the risk of taking a secondary role in the decision making concerning the presentations of artworks. Because of the lack of a unified approach in Italy, but also because of the significant costs that differentiated intervention could represent, a private conservator working on public paintings has to find compromises in terms of time and costs, when resolving problems. The case presented in this paper concerns the retouching treatment of AN OPPORTUNITY TO REFLECT ON DIFFERENCIATED RETOUCHING TECHNIQUES USED IN ITALY: METHODS AND MATERIALS. PROBLEM SOLVING IN A PRIVATE PRACTICE CONTEXT. Leonardo Severini E-mail address: [email protected]

1. MAIN TEXT The crucial subject of retouching and chromatic compensation of paint losses has, over the centuries, received a great number of solutions, materials and techniques. Restorers are called to intervene on the face of paintings with the risk of altering the original aspect of the artwork. [1] The extents, limits and methods of loss reintegration have been the subject of international debates and attempts were made to impose regulations. In general conservators are in agreement on the reversibility a cycle of seven large panels painted by Giuseppe Valeriano and Scipione Pulzone for the Chiesa del Gesù in Rome at the end of XVI century. Removing opaque coatings, old retouching and overlaid fills, the Superintendence decided for a visible intervention in a large amount of losses. We therefore decided to apply method of selezione cromatica carried out with hatching in varnish colors onto a flat chromatic tempera base laid on the fillings. Keywords chromatic compensation of paint losses; Differenciated retouching; Hatching treatments; Inpainting; Retouching techniques; Selezione Cromatica; Visible retouching. of the materials to be used and the limitation of retouching only inside the losses, but currently there are various methods to do that. The Italian position in this matter was to propose an unusual choice of re-integration using the differentiated techniques, reflecting a specific rationale of systems in order to give as much visibility as possible of the autograph parts of a painting with no later additions. They were originally conceived to avoid the risk of falsification caused by deceptive or cosmetic retouching, not considered a valid response to the aim of making original text distinguishable. A position derived from Cesare Brandi’s thinking who refused the notion of reconstructing the areas of loss “by analogy” which he considered a falsification of history and an aesthetic offense. Visible retouching aims at reintegrating the image by reducing the visual impact of the losses while ensuring that the restoration is clearly recognizable upon close inspection, in such a way that it neither competes with the original nor conceals the traces of time. The goal of these methods was to obtain an objective, rational and scientifically based inpainting tool limiting the subjectivity of restorers [2]. The techniques of differentiated intervention on paint losses in Italy are two: Roman tratteggio and Florentine selezione cromatica. The reason why there are two different techniques is because there are two Italian public Institutes of conservation of paintings: ISCR in Rome (Istituto Superiore per la Conservazione ed il Restauro; founded in1939) and OPD in Florence (Opificio delle Pietre Dure; founded in 1975). [3][4] These two institutes belong to the Ministry for Cultural Heritage (MIBACT: Ministero dei Beni e delle Attività Culturali e del Turismo) and they considerably affect the choices of the officials who supervise the conservation of public works. [5][6] The diffusion of the two methods is linked to the areas of influence of the two National Institutes along the Italian territory [7]. In any case these two methods evolved over time with experimentations and

24 Leonardo Severini variations [8][9] adapted to specific cases. Nevertheless the differentiated techniques are presented and taught (frankly not always properly) by both the national schools (ISCR and OPD) as practically the only solution to lacunae reintegration, without acknowledging the possibility of using the mimetic method, which is considered as falsifying in the context of public education. It must be considered however that restorers with their own private studios work both for public institutions and private collectors, who never ask for a differentiated treatment! “Conservators became bilingual so to speak” [7], meaning that they used differentiated inpainting for most public paintings and mimetic treatment for everything else. Therefore the overview of the situation in Italy is slightly complicated as you can find different retouching solutions within the same museum, collection or church. It depends on a lot of factors; generally decisions are taken by public conservation institutions and government ministry officials (most of whom are art historians) that should verify the quality and rightness of the interventions but also often decide which methods have to be used. It’s a matter of fact that only in few cases do directors of conservation treatments decide to choose the option of visible retouching, that is used less and less often, because it takes longer and therefore costs much more and is not always well executed. So it’s important to know the procedures perfectly in order to do a satisfactory job. Both methods are technically built up by juxtaposition of fine brush strokes of pure transparent color (usually watercolor) applied with an hatching technique. Their differences mainly consist in the direction of brushstrokes: vertical for the tratteggio and following forms and pictorial ductus in selezione cromatica. [10] When looking at the painting in the normal way, hatched colors melt together producing a sense of wholeness. The technique is similar to that adopted by Italian Divisionist or Neo-Impressionist painters who tried to obtain an effect of maximum luminosity and brightness by taking advantage of the additive color mix phenomenon. The case presented in this paper is the retouching treatment of a cycle of large panels using selezione cromatica technique. The conservation treatment, that took more than three years to complete, was on seven large paintings (2,50 meters height each) by Giuseppe Valeriano and Scipione Pulzone at the end of the XVI century for the Cappella della Madonna della Strada inside the Chiesa del Gesù, the mother church of Jesuits in Rome. The cycle represents one of the most important example of pictures from the Counter-Reformation. [11] The artists were called to decorate an entire chapel with Stories of the Virgin and they chose to use the oil on wood technique especially because the panels, fitted with hinges, had to cover the greatly valued treasure of the church: the relics. In fact at the back side of each of the seven Figure 1 • Walk-in of the Chapel of Madonna della Strada after treatment. Figure 2 • Orthophotography of the Chapel of Madonna della Strada after treatment.

An opportunity to reflect on differenciated retouching techniques used in italy: methods and materials. Problem solving in a private practice context. 25 panels in-wall shrines are jealously conserved. The need for intervention was due to the structural problems of stability of supports. To obtain a correct intervention on the wooden panels and consolidation of paint layers we had to remove opaque coatings, old retouching and overlaid fills. Once the wooden supports were stabilized, the situation after the conclusion of the cleaning operation revealed on the painted side many extensive areas of losses. The question was which kind of retouching method should we adopt in this case? The Public official from Superintendence of Rome, an art historian, in charge of the intervention decided in favor of differentiated way of inpainting following the principle of visibility. Therefore I decided to apply the method of selezione cromatica not traditionally carried out with watercolors on white fills ground but through hatching treatment in varnish colors (Gamblin Conservation colors) onto a flat and even chromatic base tempera gouache (Schmincke gouache colors) laid on the fillings. [12] The use of a chromatic base is a practical expedient that greatly reduces the time needed to carry out the job, and the amount of varnishcolor retouching needed. At the same time it preserves the infilled surface, by creating a protective “skin”, which is morphologically similar to the surface of oil paint and therefore reduces the porosity of the gesso fillings. The filling was texurized with liquid putty. Texturing of the fills is important to obtain the optimal visual integration of the treated area, especially for varnished objects. The definite matching of the color has been carried out with strokes of three-toned varnish color after a first protective coating of varnish. To obtain a vibrant effect it is important that the brush is loaded in such a way as to produce a dense, sharp, distinct stroke of color that is not rigid (as in Figure 3 • the paintings after cleaning with losses already filled with gesso and rabbit skin glue. Figure 4 and 4bis • details with chromatic bases (left) and after hatching treatments with varnish colors (right). Figure 5 • detail with filled lacunas (left) and after hatching treatment (right).

26 Leonardo Severini tratteggio) but short and fractionally curved. Here it is important to select of paintbrush, solvents and quality of palette and materials used carefully. 4. CONCLUSIONS This kind of hatching reintegration, if not done well and subtly, can be perceived as an evident foreign element. [13] Although the Italian differentiated method appears to be very complex and is rarely requested, It is important nevertheless to know the correct application methods not only to respect the principle of visibility and recognisability of retouches from original parts but also to acquire a different perception of integration also useful for any kind of retouching techniques. By choosing pure colours, primary and secondary, splitting the tonality using subtractive synthesis we can match the colour in order to get the best result in terms of saturation, brightness, depth and vibrancy of the inpainting in a reasonable time and corresponding to the budget planned. REFERENCES Scientific article: [1] LACUNA, Atti dei convegni 2002/3 al Salone del Restauro di Ferrara. Edifir editore, Firenze 2004. [2] Muir K., Approaches to the reintegration of paint loss: theory and practice in the conservation of easel paintings. In IIC Reviews in Conservation n°10 2009. Figure 7 • detail of selezione cromatica with distinct few brushstrokes of pure color to match tonality Figure 6 • detail of selezione cromatica with distinct few brushstrokes of pure color to match tonality

An opportunity to reflect on differenciated retouching techniques used in italy: methods and materials. Problem solving in a private practice context. 27 Figure 8 • the seven panels after treatment [3] Brandi C., Teoria del Restauro, Rome 1963. [4] Baldini U., Teoria del Restauro e Unità di Metodologia, Nardini ed. Firenze 1988. [5] Bonsanti G., Theory, methodology, and practical applications – painting conservation in Italy in the twentieth century. In: EARLY ITALIAN PAINTINGS: Approaches To Conservation. Proceeding of a Symposium at the Yale University Art Gallery (April 2002) edited by P. Sherwin Garland, YUAG 2003. [6] Reifsnyder J.M., Cesare Brandi and Italian conservation theory: In and out of context. In Postprints: American Institute for Conservation – Paintings Speciality Group 16:23-32. 2003. [7] Olsson N., From mimetic to differentiated: traditions and current practices in Italian inpainting. In Postprints: American Institute for Conservation (AIC) - Speciality Group 16 (2003) 23-32. [8] Betts P., Italian differentiated inpainting techniques: a review. In PAINTING CONSERVATION CATALOGUE VOL.3. INPAINTING The Painting Speciality Group of the American Institute for Conservation of Historic and Artistic Works (AIC), C. A. Metzger (ed.), C. Maines (ed.), J. Dunn (ed.), 2011. [9] Ramsay L., An introduction to visible Italian retouching techniques. Postprints of the Image Re-integration Conference. 15-17 sept. 2003 Northumbria University. Newcastle upon Tyne, UK. Northumbria University press. 2007 [10] Ciatti M., Approaches to retouching and restoration: pictorial restoration in Italy, in Early Italian Paintings: approaches to conservation. Proceeding of a Symposium at the Yale University Art Gallery (April 2002) edited by P. Sherwin Garland, YUAG 2003. [11] Leone G., (a cura di) Le storie della Vergine nella Cappella della Madonna della Strada al Gesù - Il restauro. Gangemi editore 2017. [12] Christensen C., Inpainting binders and media: guache. In PAINTING CONSERVATION CATALOGUE VOL.3. INPAINTING The Painting Speciality Group of the American Institute for Conservation of Historic and Artistic Works (AIC), C. A. Metzger (ed.), C. Maines (ed.), J. Dunn (ed.), 2011. [13] Severini L., et al. An unusual case of integration and its solution, in: MIXING AND MATCHING Approaches to Retouching Paintings. Archetype Publications in association with ICON, BAPCR. 2010. Website: [14] www.leonardoseverini.it

Abstract This paper reviews the notion of neutral retouching in conservation. This approach, since its first use in the 19th century, has always had proponents and detractors. Today, the distrust of the notion is such that we could say it suffers from a bad reputation. The meaning ascribed to the term “neutral” can differ from one author to another. The terminological validity of the word is problematic in itself: conservators need to be cautious when using it. For ethically conscious conservators, it is important to overcome the lack of popularity of neutral retouching and to give it the attention it deserves. THE BAD REPUTATION OF NEUTRAL RETOUCHING Eve Bouyer Centre de Recherches en Archéologie et Patrimoine, Université libre de Bruxelles; CP 133/01, Avenue F.D. Roosevelt, 50, B-1050 Brussels; Eve. [email protected]

1. INTRODUCTION A neutral restoration can be done on any multicolour object: paintings, polychrome sculptures, decorated ceramics, posters, etc. The term “neutral” can be understood in different – even contradictory – ways, as will be shown in the third part of this paper. Broadly, “neutralising” means reducing the inconvenience caused by lacunas without reconstructing them. 2. HISTORICAL PERSPECTIVE ON THE USE AND REPUTATION OF NEUTRAL RETOUCHING Although the term “neutral” was most likely used first in the field of painting restoration, neutral interventions were realised earlier in other fields. A red-figured vase restored around 1830-40 is evidence of this: it still has a lacuna filled with a flat uniform colour matching the underlying reddish colour [1]. Marco Ciatti attributes the first explicit Keywords Neutral; Visible restoration; Aesthetics; Ethics; Terminology. textual reference to neutral retouching to the Italian art historian Giovanni Battista Cavalcaselle (1819-1897) [2], who stated that restorations should be recognisable to the naked eye in order for scholars not to be deceived. Directly influenced by Cavalcaselle’s ideas, the first neutral integration on a painting was made in 1858- 1861 by Gaetano Bianchi, on Piero della Francesca’s frescoes depicting the legend of the true cross, in the San Francesco Church in Arezzo [3; 4]. Once he had attained a ministerial post, Cavalcaselle imposed neutral toning throughout the recently united Italian Kingdom via a circular published 30 January 1877, which states lacunas were to be filled with a colour matching but less intense than the surrounding colour(s) [2; 4]. Neutral toning quickly became the subject of controversy and some restorers, such as Cosimo Conti, clearly expressed their disagreement with the ministerial guidelines [4]. Other restorers such as Filippo Fiscali completely aligned with Cavalcaselle’s recommendations. Fiscali is responsible for an interesting example of neutral integration made around 1890 on Benozzo Gozzoli’s frescoes at San Francesco Church in Montefalco [4]. In The Death of the Knight of Celano, an extensive lacuna was filled with a single brown colour matching the predominant colour of the scene but in a duller version (a colour photograph can be seen on the Wikiart website [5]). The ministerial guidelines were mentioned in Conservare o restaurare?, the famous 1893 essay by Camillo Boito written in the form of a dialogue: “Veda, per i quadri e per i dipinti a buon fresco un ordine circolare del Ministero impone che le lacune ed i buchi si riempiano di tinta neutra tutta uguale, sicché il riguardante non possa venire menato per il naso dall’abile restauratore” [6]. (You see, for panels and frescoes, a ministerial circular requires that lacunae and holes are filled with uniform neutral tint, so the viewer cannot be led by the nose by the skilled restorer). The lines following this quote indicate the existence of an early debate about neutral restoration. One

30 Eve Bouyer protagonist in Boito’s dialogue claims that it disrupts aesthetic pleasure, and is unjustified where completion is nonconjectural. The other responds that, to him, having doubts concerning the painting’s authenticity is much more disruptive [6; 7]. Another early critique of neutral retouching was formulated in 1903 by the architect Giuseppe Sacconi, who was in charge of the restoration work in the upper Basilica of Assisi. Commenting on Giotto’s St Francis mourned by St Clare, he wrote that the choice of a single neutral colour for a painting can be wrong: “In many areas, it will appear dark against light, and vice versa…and will be more disturbing to the eye than a simple loss of paint from the intonaco” [4]. Neutral retouching had a lot of success in Germany in the 1920s and in Europe in the mid-20th century [8; 9]. This can be linked to a purist tendency called “archaeological” or “analytical restoration” that strongly rejected illusionism [3]. Artworks were perceived merely as historical documents, and their aesthetic value was put aside. In the name of authenticity, later additions were systematically removed and all losses were treated with a minimal, “archaeological” approach, where neutral integrations were the logical choice. Even if quite popular, neutral toning coexisted with more reconstructive approaches [2], and kept being criticised: German publications in 1928 reflected a profound debate between proponents and detractors of neutral retouching [10]. The same publications show that neutral restoration was often executed using grey [10]. Cesare Brandi reacted to the success of neutral retouching by promoting a new compromise – the tratteggio. For the sake of the artwork’s “potential unity”, he advocated for a more reconstructive but still recognisable approach. However, he thought that “where conjecture begins” (to quote Article 9 of the 1964 Venice Charter), the lacunas were not to be reconstructed, even with recognisable retouching techniques. For these nonreconstructible losses, he proposed some kind of neutral restoration. Connoisseurs of Brandi’s work might – rightly – disagree that he did so, as he famously criticised the idea of neutral colour. On one hand, Brandi highlighted a terminological nonsense: neutral colours do not really exist, because any colour will always alter the perception of the artwork. On the other hand, he disagreed with how those around him executed neutral retouching: with colours resembling the original ones. Influenced by the Gestalt theory of visual perception, he believed that such colours do not blend in, but on the contrary impose themselves and thus transform lacunas into figures that interfere with the painting’s legibility. He prescribed the use of colours that force the lacunas to look like they are on another level than the painting: in the foreground or – preferably – in the background [11]. One could consider this as some kind of neutral restoration, since it was intended to reduce the inconvenience caused by non-reconstructible lacunas (in the broad sense mentioned at the beginning of this paper). Similarly, Laura and Paolo Mora and Paul Philippot considered some losses non-reconstructible and wrote that “neutral tint” is “a totally inadequate term and a wrong notion, the misuse of which is usually nothing more than an excuse for avoiding the critical problem”. They recommended filling these losses in with the natural texture and colour of the arriccio [12]. In the same vein, Umberto Baldini considered that some lacunas are reconstructible, while others are not. For the former, he devised the selezione cromatica and for the latter, a new and very elaborate form of neutral retouching: the astrazione cromatica [13].

31 The bad reputation of neutral retouching Neutral toning embodies a purist tendency in conservation that flourished over a few decades of the 20th century. Brandi can be seen as a starting point for a reaction against this purism. The famous painting conservator Helmut Ruhemann is a prime example of this change in attitude. Initially, he promoted neutral retouching: in a 1931 paper, he explained that in order to “neutralise” the effect of paint losses, he used flat colours similar to either those surrounding the lacunas or the brownish underpainting [14]. But in 1968, he declared himself against “too visible” retouchings, acknowledging reconstructive ones, tratteggio included [15]. Conservators used to worry mainly about the material authenticity of artworks, in reaction to past excesses of deceptive and unethical restoration. But with the consolidation of ethical guidelines in conservation practice (reversibility and no overpainting of the original), attention to aesthetics regained its original importance. This helps explaining why neutral retouching increasingly earned a bad reputation. This is made obvious by the fact that today the term “neutral” is frequently used within quotation marks and/or preceded by the locution “so-called” [3; 9; 16]. This clearly suggests that neutrality is a myth in restoration. Critique might have reached a paroxysm in a book by Knut Nicolaus published at the end of the 1990s in several languages. Nicolaus associates neutral toning with a form of dogmatism, which is a severe accusation. And even more extreme, he states that he observed its use mainly among conservators who struggle with mimetic or normal retouching [17]. 3. WHAT IS REALLY MEANT BY “NEUTRAL” ? Meanings ascribed to the term “neutral” can be contradictory and lead to misunderstandings. This is well illustrated by a short LinkedIn discussion entitled “The Diplomatic Neutral Colour” [18]. It was launched in 2017 by Rita Udina, a book and paper conservator from Spain. She wrote that it can be a “good solution” and provided a link to her personal weblog showing an example of neutral retouching on a poster, with a flat uniform blue colour closely matching the one surrounding the large lacuna [19] (figure 1). Sheila Landi, a textile conservator in the UK, strongly reacted to the LinkedIn post, writing, “There is no such thing. As far as textiles are concerned trying to dye a ‘neutral colour’ it always ends up too green, too pink or too yellow. If used as a background for other colours all the so called neutral colour does is kill the object stone dead.” A first observation is that “neutral” might not be as “diplomatic” as the title of Udina’s post suggests. Secondly, Landi Figure 1 • Paper poster, «In the name of peace and progress!», Valentin Viktorov, 1959 © Rita Udina (http://ritaudina.com/

32 Eve Bouyer and Udina most likely have a completely different understanding of the term “neutral”. Indeed: a neutral colour might mean either matching a colour that appears on the original or choosing one extraneous to the original. The 1940 Manual for the Conservation of Paintings proves that this terminological ambiguity is not new. The adjective “neutral” was indeed used twice in the book: first, it mentioned a “neutral tint that matches the surrounding colour”, then referred to “neutral grey” [20]. When matching (more or less closely) a colour that appears on the original, there are at least three options. First, matching the main colour that surrounds a lacuna (figures 1 and 6). Because of the multiple meanings of the word “neutral”, the author of this paper proposes calling this option the surrounding colour. It was mentioned by Helmut Ruhemann [14] and in the 1940 Manual on the conservation of paintings [20]. A second option is choosing the colour that predominates on the whole object (figure 2). The author of this paper proposes calling this option the predominant colour. This corresponds to the definition of neutral tint provided by Ségolène Bergeon, who gives a good example: Pietro Perugino’s Resurrection from a predella with scenes of the life of St Jerome, in the Louvre, where grey was chosen for its predominance in the scene [21]. A third option is choosing a colour that lies under the original surface, and that was not necessarily visible when the object was in pristine condition (figure 3). The author of this paper proposes calling this an underlying colour. This colour can be that of the support medium (wood, canvas, arriccio, Figure 2 • Bowl with the Martyrdom of St Lorenzo, majolica from Urbino by the Painter of the basin of Apollo, ca 1521–1532; International Museum of Ceramics in Faenza, ac. n° 4974 (A. Orombelli donation, 1952) © Faenza, Museo Internazionale delle Ceramiche clay body etc.) or of another layer (coloured preparation, intonaco, ceramic’s white glaze etc.). This option was mentioned by Paolo and Laura Mora and Paul Phillipot [12] and by Helmut Ruhemann [14]. It is sometimes called “natural neutral” [8] or “background colour” [22]. In most instances, there is a drastic difference between the predominant and the underlying options, but with some artworks, they can be the same colour (figure 4). Aside from these three options, one can otherwise choose colours extraneous to the original. Indeed, when choosing one of the original colours seems difficult or Figure 3 • Basin with the Presentation of the Head of Pompeo to Caesar, majolica from Casteldurante, ca 1535–1540; International Museum of Ceramics in Faenza, ac. n° 10570 (M. Pedicini donation, 1960) © Faenza, Museo Internazionale delle Ceramiche

The bad reputation of neutral retouching 33 Figure 4 • Mina’i jar, polychrome stonepaste from Iran, 12th–13th century; The Metropolitan Museum of Art, ac. n° 17.120.183 (Bequest of Isaac D. Fletcher, 1917) © The Metropolitan Museum of Art (www.metmuseum. org) visually inappropriate, it is possible to select a new one that resembles a “blend” of the colours surrounding the lacuna (figure 5). The author of this paper proposes calling this an intermediate colour, term used in a paper by Meg Loew Craft [23]. An alien colour is applied to the object, but it still somewhat ressembles the original colours. In some cases, especially when the object shows a high contrast ratio, it might result in a dirty-looking colour, which is not very pleasing to the eye [24]. The fifth and last option the author identified is an extraneous colour which is not chosen for having a resemblance to the original colours but because it is supposed not to influence their perception. We propose to call this an unrelated colour. In practice, it is often a grey or beige colour. Some interesting examples are: • The 1940 restoration of Lorenzo Monaco’s Coronation of the Virgin, and the 1982 restoration of Duccio’s Annunciation, both conserved in the National Gallery and showing grey neutral integrations [9]. • The 1990 restoration of Piero della Francesca’s frescoes in Arezzo, particularly the scene depicting the victory of Constantine, which shows grey and beige neutral integrations (colour photographs can be seen on an interactive online feature [25]). • The 2000s restoration of a fresco cycle in the Neues Museum of Berlin: Aus dem Sagenkreis der Edda, by Gustav Heidenreich, Gustav Richter and Robert Müller; devastated during the Second World War, it shows today grey neutral integrations. Here, we approach the definition of neutral colour from fields other than conservation. To colour specialists, neutral precisely means achromatic colours: pure black, pure white and pure greys. Interior designers generally include as well colours similar to achromatics but that nevertheless Figure 5 • Bowl with Griffin, luster-painted earthenware from Egypt, 11th century; The Metropolitan Museum of Art, ac. n° 1970.23 (Louis E. Seley gift, 1970) © The Metropolitan Museum of Art (www.metmuseum.org) show an undertone, such as beige, taupe, off-white etc. Neutral grey is frequently mentioned in the literature, and apparently had a great success in Germany as early as the 1920s [8; 10]. It was devised with the good intention of being unobtrusive: because grey is supposed to be the result one would obtain by mixing all colours together, it was thought to be compatible with all original colours [10]. This usage was however soon criticised. Already in 1940, the Manual on the Conservation of Paintings called it “a fiction: it will always assume the complementary tones of the neighbouring colours, thus introducing an alien element into the painting” [20]. The same observation was made in 1968 by Ruhemann: “However grey a tinge may be in itself, the neighbouring or surrounding colour will give it, by contrast, a more colourful hue; and the most important rule is not to introduce any alien shade into the painting; if grey is not in it, none must

34 Eve Bouyer be added” [15]. These comments have something in common with those written by Sheila Landi; the author of this paper thinks that she might have had this understanding of the term “neutral” in mind when she reacted to Rita Udina’s post. Apart from these purely chromatic issues, executing a neutral retouching does not necessarily mean filling in all the lacunas of a given object with the same colour. It can also correspond to using several colours depending on the areas. It can be one colour per lacuna (figure 6) or several colours in the same lacuna that indicate the lost shapes without reconstructing details, as suggeted by Dimitrios Doumas [26]. Good examples of neutral integration with several colours in the same lacuna include: • The 1958 restoration of the main panel of Giovanni da Milano’s polyptych conserved in the Museo civico del Prato, qualified as “matching neutral” by Marco Ciatti [2]. • The 1972 restoration of two panels by Ugolino di Nerio (Isaiah and a diptych with Saints Simon and Thaddeus), both conserved in the National Gallery: they are considered neutral by some authors because of their flat unmodulated colours [9; 17]. Other examples can be seen in the European Illustrated Glossary of Conservation Terms for Wall Paintings and Architectural Surfaces [16] and in a paper by Dimitrios Doumas [26]. Not everyone considers this option as neutral; Jilleen Nadolny calls it “suggestive differentiated retouching” [8]. Indeed, it is partially – but still not fully – reconstructive. Finally, a neutral retouching does not necessarily mean a flat uniform colour. Some authors acknowledge that neutral can correspond to heterogeneous colours, notably those obtained with divisionist retouching techniques [8; 21]. It might be tratteggio, chromatic abstraction, pointillism (figure 6) or other means of making colours less flat (figure 4), such as the sponge technique. “Neutral” can mean almost anything to conservators (table 1). Should the term, which is often criticised and placed within quotation marks, be banished from the field of conservation? At the very least, it should be used with caution. Its use might be especially problematic when qualifying nouns that imply a concrete visual fact, such as colour, tone or tint. Indeed, as claimed by several authors, no colour/tone/tint can really be neutral. Even if a pure grey is neutral in isolation, it will not remain so when placed in a colourful context, which will induce chromatic interactions. Thus, it might be best to avoid such a wording. But maybe the adjective could keep being used when describing a human action, such as retouching or reintegration? Figure 6 • Bowl with Susanna and the Elders, majolica from the Fontana workshop in Urbino, ca 1545– 1550; International Museum of Ceramics in Faenza, ac. n° 6156 © Faenza, Museo Internazionale delle Ceramiche

The bad reputation of neutral retouching 35 Conservators tend to understand the term as it is used in chemistry, where neutral has a completely objective sense (neither basic nor acidic) and implies something completely innocuous, without any effect. This is of course completely impossible with reintegration issues: any choice will always affect perception of the artwork. But if we consider the term’s other uses – in geopolitics, law or sociology for instance – neutrality does not necessarily mean having no impact at all but rather “not taking sides”, staying as impartial as humanly possible. In this sense, the term “neutral” might be valid. Indeed, any neutral retouching will strongly influence the appearance of the artwork: it is not neutral as a visual fact. But it can be considered neutral as a human action, in that it expresses the desire to avoid influencing the viewer’s opinion on what used to occupy the lacunas and, in the meantime, to simply admit that the truth is unknown. 4. CONCLUSIONS Many problems regarding the terminology of conservation remain to be solved: the word “neutral” is one example among many. This paper highlights the term’s range of meanings and proposes specific terms for distinguishing the various neutral options. It also provides suggestions for using and interpreting the adjective more accurately, but the author believes reaching a terminological consensus will require much more critical thinking. Maybe it would be best to simply banish the term? But what should replace it? “Non-reconstructive”? Aesthetic displeasure is not an argument against neutral retouching. Certainly, it should not be used systematically for all types of losses, as was the case at certain points in the history of conservation: doing so would neglect the artwork’s aesthetic potential. Even if as a conservator you find it aesthetically unpleasant, there will always be cases where it is required because a reconstructive retouching would be deeply conjectural and thus unethical. In cases of deep conjecture, any attempt at reconstruction would necessarily be a personal, and thus partial, reinterpretation, liable to deceive the general public and misguide art historians in their stylistic or iconographic analyses. Because of its aesthetic implications, neutral retouching is not an easy exercise. Choosing a solution that is the least disruptive requires either natural talent or real effort to evaluate examples and assess possible options. To sum up, neutral retouching is sometimes required from an ethical point of view, but is a challenging exercise. It is therefore essential for conservators to get past prejudices against neutral retouching in order to give it the attention it deserves. TYPE OF COLOUR NUMBER OF COLOUR(S) APPLICATION OF COLOUR(S) matching the original surrounding the same colour everywhere predominant flat uniform underlying extraneous to the original intermediate several depending on the areas heterogeneous unrelated Table 1 • Summary of neutral options

36 Eve Bouyer REFERENCES [1] Bourgeois, Brigitte – La fabrique du vase grec. Connaître et restaurer l’antique dans l’Europe des lumières. Technè. N° 32 (2010), pp. 5-10. [2] Ciatti, Marco – Approaches to Retouching and Restoration: Pictorial Restoration in Italy. In Early Italian Paintings: Approaches to Conservation. Proceedings of a Symposium at the Yale University Art Gallery (April 2002). New Haven: Yale University Press, 2003, pp.191-207. [3] Schädler-Saub, Ursula – Teoria e metodologia del restauro. Italian contributions to conservation in theory and practice. In Conservation and Preservation. Interactions between Theory and Practice. In memoriam Alois Riegl (1858-1905). Firenze: ICOMOS, 2010, pp. 81-94. [4] Conti, Alessandro – A history of the restoration and conservation of works of art. Oxford: Butterworth-Heinemann, 2007, pp. 313-344. [5] Wikiart – Death of the Knight of Celano. Available at: https://www.wikiart.org/en/ benozzo-gozzoli/death-of-the-knight-of-celano [17 Nov. 2017]. [6] Boito, Camillo – I restauri in architettura. In CRIPPA, Maria Antonietta, ed. – Camillo Boito, II nuovo e l’antico in architettura. Milan: Jaca Book, 1989, pp. 122-123. [7] Boito, Camillo – Conserver ou restaurer? (1893), translated from the Italian by Mandosio Jean-Marc. Saint-Front-sur-Nizonne: Editions de l’Encyclopédie des Nuisances, 2013, pp. 46-47. [8] Nadolny, Jilleen – History of Visual Compensation for Paintings. In Hill Stoner, Joyce; Rushfield, Rebecca, ed. – Conservation of Easel Paintings. Oxon: Routledge, 2012, pp. 573-585. [9] Ackroyd, Paul; Keith, Larry; Gordon, Dillian – The Restoration of Lorenzo Monaco’s ‘Coronation of the Virgin’: Retouching and Display. National Gallery Technical Bulletin. Vol. 21 (2000), pp. 43-57. [10] von der Goltz, Michael – Is it useful to restore paintings? Aspects of a 1928 discussion on restoration in Germany and Austria. In ICOM Committee for Conservation. 12th Triennial Meeting. Lyon, 29 Augustus-3 September 1999. Vol. I, London: James & James, 1999, pp. 200-205. [11] Brandi, Cesare – Théorie de la Restauration, translated from the Italian by Déroche, Colette. Paris: Editions du patrimoine, 2001. [12] Mora, Laura; Mora, Paolo; Phillipot, Paul – Conservation of Wall Paintings. London: Butterworths, 1984, pp. 310-312. [13] Baldini, Umberto – Teoria del restauro e unità di metodologia. Firenze: Nardini Editore,2001. [14] Ruhemann, Helmut – La technique de la conservation des tableaux. Mouseion. Vol. 15, n° III (1931), pp. 19-21.

The bad reputation of neutral retouching 37 [15] Ruhemann, Helmut – Technique and Ethics of Retouching. In RUHEMANN, Helmut – The Cleaning of Paintings, 1968, pp. 240-263. [16] Weyer, Angela; Roig Picazo, Pilar; Pop, Daniel; Cassar, Jo Ann; Özköse, Aysun; Vallet, Jean-Marc; Srša, Ivan, ed. – EwaGlos. European ILLUSTRATED GLOSSARY of CONSERVATION TERMS for WALL PAINTINGS and ARCHITECTURAL SURFACES. Petersberg: Michael Imhof Verlag, 2015, p. 330. [17] Nicolaus, Knut – Manuel de Restauration des Tableaux. Köln: Könemann, 1999, p. 291. [18]LinkedIn’s Conservator-Restorer group – The Diplomatic Neutral Colour. Available at: https://www.linkedin.com/groups/94889/9 48 89-6223512192315064322 [17 Nov. 2017]. [19] Udina, Rita – The Diplomatic Neutral Colour. Available at: http://ritaudina.com/ en/2017/01/02/retouching-inpainting-paperconservation-neutral-colour-field/ [17 Nov. 2017]. [20] Manual on the conservation of paintings. Paris: International Institute of intellectual Cooperation, 1940, pp. 22 and 107. [21] Bergeon, Ségolène – «Science et patience» ou la restauration des peintures. Paris: Editions de la Réunion des musées nationaux, 1990, pp. 194 and 224-225. [22] de Lapérouse, Jean-François; Stamm, Karen; Parry, Vicki – Re-examination and Treatment of Mina’i Ceramics at The Metropolitan Museum of Art. In Glass and Ceramics Conservation 2007: Interim Meeting of the ICOM-CC Working Group, August 27– 30, 2007, Nova Gorica, Slovenia, Nova Gorica: Goriški muzej Kromberk, 2007, pp. 112–119. [23] Loew Craft, Meg – A visual review of compensation philosophies for Islamic ceramics. In Loss Compensation: Technical and Philosophical Issues. Proceedings of the Objects Specialty Group Session, 22nd Annual Meeting in Nashville, Tennessee. June 10, 1994. Vol. 2, Washington DC: The American Institute for Conservation of Historic & Artistic Works, 1994, pp. 73-88. [24] Giboteau, Yvonne; Zumstein, Isabelle; Vinçotte, Armand – Considérations sur la restauration de céramiques archéologiques, notamment sur la restitution de la couleur. Conservation-restauration des biens culturels. N° 4 (1992), pp. 12-14. [25] Institute for Advanced Study – Interactive model: The Legend of the True Cross (Piero della Francesca). Available at: http://projects.ias.edu/ pierotruecross/pieroimages.html [17 Nov. 2017]. [26] Doumas, Dimitrios – Reconstructing the Image: A discussion on the Effectiveness of Restoration Methods for Painted Surfaces. Theory and Practice at the Benaki Museum Conservation Department. Mouseio Benaki. Vol. 10 (2010), pp. 83-103 . Also available at: https://www.benaki.gr/images/researches/pdf/ Anatypo_Doumas.pdf (17 Nov. 2017].

ABSTRACT Two series of Four evangelists, eight canvasses, formerly belonging to two Baroque churches (St Blaise and Our Lady of Carmel), attributed to the Baroque artist Mattia Preti, have been restored by the HRZ, Croatian Conservation Department Dubrovnik in cooperation with Opificio delle pietre dure (Florence). The international interdisciplinary restoration and research project determined the original prototype, explored the question of copies-replicas as well as possible origins within the same workshop. The stratigrafic analysis was performed and subsequently compared to the vast data base of Mattia Preti paintings (from Taverna) in the laboratory of the Opifico delle Pietre Dure. The results of the research and the conclusions regarding the copy-replica-original topic were presented as well as the specific characteristics of the pigments used for creating the Evangelist-paintings. The retouching from the former 19th and mid20th century restorations was presented and discussed. BAROQUE MASTER MATTIA PRETI AND HIS WORKSHOPTWO SERIES OF FOUR EVANGELISTS FROM DUBROVNIK Mara Kolić Pustić (1) | Carlo Galliano Lalli (2) | Nancy von Breska Ficović (3) 1. Croatian Conservation Institute (HRZ), Conservation Department Dubrovnik, Batahovina bb, 20 000 Dubrovnik, Croatia; [email protected] 2. Opificio delle Pietre Dure e Laboratori di Restauro di Firenze, viale Filippo Strozzi 1 – Fortezza da Basso, 50129 Firenze, Italy; [email protected] 3. Senior Art Historian, Avenue des Cèdres 6, 1640 Rhode Saint Genèse, Belgium; [email protected]

1. INTRODUCTION This project focuses on two series of paintings representing the four Evangelists. These sets of four paintings were located in two Baroque ecclesiastic buildings in the inner city of Dubrovnik: the confraternity church Our Lady of Carmel (Karmen), and St Blaise (Sv. Vlaho), the church honoring the patron saint of the city. Beside the article by Croatian art historian Kruno Prijatelj1 from 1981, there was not much more to be found about these paintings for The importance of each and every step of the conservation process leading to the final phase, the retouching, and the choice of the retouching method was demonstrated. It was proved that the two series of paintings were following the same prototype/drawing. This contributed in the execution of a mimetic kind of inpainting. Details of the paintings photographed in different phases of the restoration work were presented and the chosen retouching technique was explained and substantiated in detail. Keywords Pigments; Painting technique; Mattia Preti; Original-replica-copy; Four Evangelists; Inpainting decades. Prijatelj made some analogies to Mattia Preti’s work and suggested an attribution to his workshop. 1.1 Mattia Preti Mattia Preti (Taverna, Italy, 1613 - Valetta, Malta, 1699) was a renowned Italian baroque artist and Knight of the Maltese Order. His elder brother Gregorio was also a painter active in Rome. Mattia joined him and they worked together, but very quickly he became more popular and was commissioned to execute prestigious artworks. In 1653 he moved to city of Naples until 1661, when he transferred to Malta, where he spent the rest of his long and very active life. 1.2 Croatian Conservation Institute project In 2005 the Croatian Conservation Institute (HRZ) began the restoration of the series of Evangelists from Our Lady of Carmel and their excellent quality was revealed. A year later, the paintings from St Blaise church were also included into the project with the intention of a simultaneous work and research. It was clear from the beginning that there was some kind of a connection, but at the same time, there were significant differences between the two series that needed to be clarified. 1.3 Evangelist paintings by Preti in Italy and Malta The art historian Prijatelj was familiar with the painting Four Evangelists from the Galleria Abatelis in Palermo. However, in the meantime other, almost identical paintings to the Dubrovnik Evangelists emerged in the Catalogo Reggionato by John T. Spike2 . At the beginning, only one painting Figure 1. • Four Evangelists, Our Lady of Carmel Church, before and after conservation

40 Mara Kolić Pustić | Carlo Galliano Lalli | Nancy von Breska Ficović of Mattia Preti’s Evangelists-series was known: a St Mark, in Cosenza, Italy. It seemed to be identical as the one from the Our Lady of Carmel. Spike suggested that the painting belonged to the early Maltese period of the painter. Besides that, he also mentioned, two copies of Preti’s Evangelists St Mark and St Luke, from Malta. At that point, although he was not familiar with the existence of the two complete series in Dubrovnik, he rightly came to a conclusion that the St Mark in Cosenza was a part of a series of four paintings representing the four evangelists. As to that date, there was no trace of St Matthew and St John, the Dubrovnik paintings were fundamental for a reconstruction of the iconography of the series. 1.4 New discoveries/originals-copies context During the project, more paintings belonging to the evangelists’ topic were discovered. Beside St Marc in Cosenza, the existence of another original by Preti, a St John, also in Italy, was confirmed. An information about a sold St Luke in Munich, pictured only in a black and white photo, was also found. Furthermore, the remaining two copies from Malta were traced. These discoveries shed new light on the importance of the two Dubrovnik series, making them part of a quite popular original set of paintings by Mattia Preti. 2. MATERIALS AND METHODS During restoration works it was established that the original dimensions of all eight paintings were the same. In case of the Carmel-series the linen support has a 10 cm broad, stitched addition along the right border. In comparison, the St Blaise series has been painted just on one wider piece of canvas. Interestingly, the two paintings in Italy, have the same dimensions and, besides that, they have the same sort of support as the Carmel series: the one with a 10 cm stitched addition. If we compare the 2 Dubrovnik series and the Italian one, they seem to be exactly the same up to the smallest detail. The only difference has been detected in the fringe on the forehead of the saint. As the UV fluorescence and x-rays suggested, and the different character of material has confirmed, originally that difference did not exist at all. It was a consequence of a later intervention. Figure 2. • Four Evangelists, St Blaise’s Church, before and after conservation

Baroque master Mattia Preti and his workshop- Two series of four evangelists from Dubrovnik 41 2.1 Earlier interventions The research has shown that there had been two earlier interventions on both series of paintings. An AustroHungarian, around the beginning of 20th century and a second one, done in Zagreb in the 1950-ies. During the first intervention, the linen support was mended with patches and in 1950-ies a wax and resin lining was executed. Two different interventions were also confirmed by two different sorts of fillings. In the Austro-Hungarian intervention a brown toned varnish was applied. In 1950-ies, that varnish was removed only in some, mostly brighter areas and in some areas, it was not removed at all. The fillings were applied in all damaged areas and the retouching was executed accordingly to the level of cleaning. Some filling and retouching was spreading over the original. 2.2 Stratigrafic analysis The comparative analysis of the materials used by Mattia Preti was executed in the Opificio delle Pietre Dure in Florence, by Carlo Lalli. According to the previous assumptions, Maltese materials were to be expected. Earth pigments from Malta are rich in microfossils and were found on all Preti’s paintings from that period (1661-1699). It was discovered that the preparations of all eight paintings from Dubrovnik consist of similar, almost identical materials: earth pigments, ochre, calcium carbonate, some iron oxide, carbon black and tiny chips of glass in an oily binder applied in two layers. Differences between the Dubrovnik series have been found only in quantity and granulometry. The Dubrovnik paintings, however, do not contain any microfossils. Therefore, it was concluded, despite the previous assumption, that Maltese materials were not used in the execution of the Dubrovnik series. As for the pigments in paint layer, the situation was similar. For example, the flash colour consisted of: lead white, with some green earth and carbon black, red lake, earth pigment and vermilion particles. The presence of cerussite and hydrocerussite crystals in lead white was particularly Figure 3. • Detail of the forehead, St Mark the Evangelist, Our Lady of Carmel Church: a) during cleaning in visible light; b) x-ray during cleaning; c) during cleaning in UV light; d) after conservation

42 Mara Kolić Pustić | Carlo Galliano Lalli | Nancy von Breska Ficović interesting. The very same ingredients were actually found in the flesh colour on all paintings of both series. The black pigments appeared to be interesting too. The presence of a rare carbon black with high percentage of Sulphur was detected in both series. However, in case of the blue colour, another black pigment was used - the bone black. It was added to indigo along with the lead white. Again, the same pigment mixture was found on both series of Dubrovnik paintings. 2.3 Analysis conclusions In respect of all the findings – the following conclusion could be made: The measures of all Dubrovnik as well as the Italian paintings are the same. The linen support with the stitched addition on the right side is the same for Carmel Dubrovnik series as well as for the two Italian paintings. These two series can be considered as work of Mattia Preti and his assistants and therefore, one could be a replica of the other. The St Blaise series was created on base of the same drawing, probably in the same workshop but not in the same time, but consisting of very similar if not identical materials in preparation and in the paint layer. In that case the art historians and painting conservators are unanimous in conclusion that the St Blaise series was painted by another hand and can be considered as a workshop replica. In respect to that - the paintings from Malta can be considered as later copies with different proportions, absence of architectural elements and completely different painting skill. 3. RETOUCHING It is important to stress that all previous phases of conservationrestoration work are the ones that contribute and define the final inpainting phase. Each and every phase of work, when done properly, reduces and simplifies the final retouching process. If we do not manage to do the uniformed and thorough cleaning up to a chosen point and leave some “problems” to be resolved by the final inpainting phase or if we do not blend in the character of the filled area into Figure 6. • Detail of the forehead of the Child, St Luke the Evangelist: a) Our Lady of Carmel Church, gouache underpainting; b) Our Lady of Carmel Church, after conservation; c) St Blaise’s Church Figure 5. • Detail of St Luke’s eyes, St Luke the Evangelist, Our Lady of Carmel Church: a) after filling; b) after filling in raking light; c) after conservation Figure 4. • Taverna, the microfossils are visible; c) St Mark the Evangelist, St Blaise’s Church, Dubrovnik; d) St Mark the Evangelist, Carmel Church, Dubrovnik

Baroque master Mattia Preti and his workshop- Two series of four evangelists from Dubrovnik 43 the original one, the inpainting process will be burdened by issues that should have been resolved in earlier phases of work and the conservator will be confronted with the challenge to “cover” and “mask” those issues with colour in final phase of work. Even if we are brilliant in that skill, the result will never be as good as the one when all phases are done thoroughly. As for the choice of a retouching method to be done, the decision was quite simple. The missing areas were not too big or hard to define, and having more paintings with the same motive made it even easier to choose the complete integration of missing areas into the original as a concept of a retouching. A good example of a potentially puzzling situation could be the area of the St Luke painting. The forehead of the Child could be interpreted as either damaged or left as unfinished on purpose - because St Luke, the painter, has not yet finished his work. In this case, with more paintings to compare, it was quite certain that we were not dealing with a superficial damage, but with an intentional “unfinished” area of a painting. The filling was based on plextol binder and brown earth, pigment filler close to the original preparation in tone.3 3.1 Underpainting The procedure of working with gouache4 can be described in several steps: 1. We start with a middle tone for a certain zone; 2. It is applied to the whole area of the same colour; 3. The next step is building up the shadows or lights in a way that a similar transparent layer will be needed for the whole area to blend it in into the original; 4. After completing the gouache underpainting, the first layer of varnish is applied with a brush. 3.2 “Colori a vernice”- glazing As for the final glazes, a selection of high quality stable pigments, Canada balsam and - optionally - a small quantity of varnish is needed. If the granulation of a pigment is not fine enough, it is necessary to grind it until it is. Earlier, shellsol T was used to wet the pigments during the grinding procedure, but distilled water and/or ethanol instead, seem to be more efficient and easier to control. It’s interesting to notice how much the tone sometimes changes in respect to a different granulometry. It’s good to keep that in mind for some certain cases when we do not need the transparency, but do need a darker tone. For example, on these paintings, in some situations the blacks were simply not black enough. For preparation of colours, a maximum possible quantity of pigment up to a saturation of the binder is needed. If there is too much binder, the colours tend to be less soluble with time and to transparent and shiny. The Canada balsam tends to get denser with time. Because its consistency is crucial for getting the right ratio of pigment and balsam, it’s good to know that Canada balsam can be successfully diluted with some ethyl-l-lactate. Once made, the colours are positioned on a plexiglas palette where they dry and can be resolved by different sorts of mediums (for example ethyl-l-lactate and acetone mixture).

44 Mara Kolić Pustić | Carlo Galliano Lalli | Nancy von Breska Ficović The role of the more volatile solvent is to control the speed of drying which becomes important in applying of every next layer to avoid dissolving the previous one. It is also important to have patience, to let each layer dry completely before proceeding. Furthermore, some brown colours tend to be less soluble once they are dry on the palette. For such cases, sometimes it helps if a drop of varnish is added to the mixture while preparing the colours. These colours do not darken with time. If they do change, they get a bit brighter, and, if necessary, it is quite simple to darken them some more. 4. CONCLUSIONS The described retouching method was introduced to Conservation department Dubrovnik by the Florentine colleague Stefano Scarpelli. It’s not a revolutionary method, on the contrary, it is a classic. Although, it is quite obvious that this was not the case of some specific approach, motivated by some particular situation, it is important to stress that presenting and discussing the “common”, “simple” situations can sometimes be left in a shadow and can be taken for granted. In fact, the “classical”, “usual” procedures need to be shared more. They are common and simple for those who know how to perform them, but not that simple for those who do not yet have the knowledge and the skill. The best way to learn, beside all the explanations and conferences, is simply to watch someone more experienced doing it. On the other hand, however experienced we are, there is always some space left for improvement and modifications. It can always get better. Finally, it is not only important to make a right choice of the materials that we are going to use. We also need to know how to use them and that can make a huge difference. There is no guarantee of doing a good job just because having used some suggested quality materials. The two Dubrovnik series are a perfect example to make that point: As elaborated, the same composition, same drawing was used as a base for the paintings, the same materials were applied and yet, the result is not slightly, but obviously different. However, much a conservator tries to be “invisible” and to let the work of art be dominant, his contribution is always present and it is always a kind of an interpretation that had been chosen. The retouching intervention becomes a part of a “life” of a work of art. We need to be aware of that and try to make the best of it. Figure 8. • Detail of the eagle, St John the Evangelist: a) Our Lady of Carmel Church, after filling; b) Our Lady of Carmel Church, after underpainting; c) Our Lady of Carmel Church, after conservation; d) private property, Italy Figure 7. • Detail of the parchment, St John the Evangelist, Our Lady of Carmel Church: a) after filling; b) after underpainting; c) after conservation

Baroque master Mattia Preti and his workshop- Two series of four evangelists from Dubrovnik 45 REFERENCES [1] LALLI, Carlo Galliano; VON BRESKAFICOVIĆ, Nancy; INNOCENTI, Federica; KOLIĆ PUSTIĆ, Mara – Le due serie dei quattro Evangelisti di Mattia Preti a Dubrovnik: un progetto multidisciplinare e di collaborazione tra il Laboratoria Scientifico dell’Opificio e l’Istituto croato di Restauro. OPD Restauro. Vol. 26 (2014), pp. 231-248 [2] KOLIĆ PUSTIĆ Mara – Tragom dubrovačkih naručitelja slika s područja južne Italije u baroknom razdoblju. Umjetnost i naručitelji, Zbornik Dana Cvita Fiskovića. Vol 3 (2010), pp.101-109 [3] KOLIĆ PUSTIĆ, Mara, ed. - The Four Evangelists in the Oeuvre of Mattia Preti, The Croatian Conservation Institute, 2009. [4] T. SPIKE, John – Catalogo ragionato dei dipinti, Centro Di, 1999. [5] PRIJATELJ, Kruno – Prilog odjeku Caravaggia u Dalmaciji, Peristil. Vol. 24 (1981), pp. 72-76 [6]Croatian Conservation Institute. Official website http://www.h-r-z.hr/en/index.php/spotlight/vijesti/1090-presentation-of-the-conservation-project-qthe-four-evangelists-in-the-oeuvre-of mattia-pretiq [7] SCARPELLI, Stefano”Il Restauro” ghirladnaio di Vallombrosa, “un restauro difficile, un ritorno trionfale” a cura di Caterina Caneva, ed Edifir Firenze, giugno 2006, pp. 48,49 [8] Museo degli Uffizi, “La Medusa di Caravaggio restaurata” a cura di Caterina Caneva. Saggio restauro ed retablo, Roma 2002 [9] Kermes rivista, “Una tempestiva risposta per la salvaguardia del patrimonio artistico di Dubrovnik” [10] Gli Uffizi, Studi e ricerche, No 14 “Nota di restauro” Cena con sposali di Gerardo delle Notti. I restauri dell’attentato, construtivo 1993-1995, ed Centro Di, Firenze 1995, pp.21-22 NOTES 1 Prijatelj Kruno Prijatelj, - Prilog odjeku Caravaggia u Dalmaciji, Peristil 24, Zagreb (1981), p. 73 2 John T. Spike, Catalogo ragionato dei dipinti, Centro Di, 1999 3 Filling: 10g binder (Lascaux Akrylkleber 498HV) + 40g water + 40g filler (pigment Iseo Braun - Kremer) 4 W&N selection of gouache colours with good stability characteristics is the one that was used

Abstract A project concerning the conservation and restoration of Girolamo da Santa Croce’s All Saints (All Saints’ Church, Korčula, Croatia) was carried out by the Dubrovnik Department of the Croatian Conservation Institute (HRZ) from 2013 to 2016. The treatment was primarily undertaken because of structural problems, since the original painting materials had become increasingly unstable. Moreover, the materials applied in previous interventions had aged poorly, resulting in overall degradation of the paint layer and thus compromising the proper reading of the artwork. Along with the stabilization of the panel and the paint layer, the inpainting (retouching) process turned out to be the most complex part of the restoration treatment. While relatively small lacunae were distributed over the entire surface of the painting, the lower area of the composition - depicting bicoloured floor tiles (pavement) – had sustained major material loss. The visual impact created by the pronounced cracks turned out to have a crucial effect on the viewer’s colour perception, not only “ALL SAINTS ARE IN THE DETAIL“: RETOUCHING A PAINTING BY GIROLAMO DA SANTA CROCE Katarina Alamat Kusjanović (1) | Sandra Šustić (2) 1. Croatian Conservation Institute (HRZ), Dubrovnik Department for Conservation, Batahovina bb, 20 000 Dubrovnik - Croatia; katarina.ak@gmail. com 2. Arts Academy of the University of Split, Zagrebačka 3, 21000 Split - Croatia; [email protected] 1 Head of the project: Katarina Alamat Kusjanović ; contributors: Antonio Blašković, Ivana Ćustović, Elio Karamatić, Mara Kolić Pustić, Sanja Pujo, and Sandra Šustić

1. INTRODUCTION The All Saints is a tempera painting by Girolamo da Santa Croce commissioned in 1540 as the altarpiece for the Church of All Saints on the Island of Korčula (Croatia). in the pavement area but also in all the painting’s bright parts. Furthermore, the smooth texture of the panel and the consequent colour reflection required outstanding precision in the retouching process as well as the use of the finest materials in order to achieve credibility for the reconstructed areas. Keywords Girolamo da Santa Croce, Panel painting, Mimetic retouching, Age-related craquelure, Reconstruction, Canada balsam It was painted on a relatively large wooden support (219 × 187 cm), consisting of six horizontal boards. Saint Peter, depicted as the Pope, stands in the composition’s center surrounded by St. Jerome and St. John the Baptist with three musician angels below his feet. The side parts of the composition display a group of 36 figures which includes apostles, evangelists, prophets, patriarchs, female and male saints, among others. The whole is topped by three arches and the Holy Spirit represented by a white dove. Horizontal and vertical accents of the composition give an effect of orderliness and repose (figure 1). [1] 1.1. Physical history of the painting and its influence on the decisions in retouching Historical records found at the Archive of the Conservation Figure 1 • The All Saints by Girolamo da Santa Croce (1540) before and after restoration. Photo © Vlaho Pustić / Ljubo Gamulin

48 Katarina Alamat Kusjanović | Sandra Šustić Department in Split made evident that the painting has undergone significant restoration treatments in the past, specifically due to the severe flaking of the paint layer. Condition report from 1959 describes the presence of a cradle on the back of the panel “probably made in the time of Austro-Hungarian Empire” and excessive damages in the paint layer: “The condition of the painting is very bad (…) the paint detaches from the wood and slides down.“ Despite the consolidation treatment performed in 1959, the dossier from 1977 reported another extensive consolidation of the paint layer. [2] Due to identical structural problems the painting was transported to Dubrovnik Department of the Croatian Conservation Institute in 2013 – severe flaking and increasing instability of the paint layer were again evident on the entire surface. In addition, the materials applied in the 1977 intervention had aged considerably, resulting in overall degradation of the paint layer and thus compromising the proper reading of the artwork (figure 2). A detailed technical study of the support and the paint layer indicated that the artist’s original technology was quite poor. The impregnation of the wooden support had lost most of its adhesive power. The aging of the materials in uncontrolled and varying climate in the church along with the inadequate cradle mounted on the back of the panel, have contributed to the development of particularly dense age-related cracks in the paint and primer layers. The visual impact of the cracking is highly pronounced - especially in the bright areas of the composition. This is due to the build-up of particularly Figure 2 • Details of the painting before treatment. Note the severe flaking of the paint layer. Photo © Vlaho Pustić Figure 3 • The painting after cleaning and filling of the lacuna. Photo © Vlaho Pustić

“All saints are in the detail“: retouching a painting by girolamo da Santa Croce 49 dark residues in the cupped paint fragments as a consequence of the consolidation and cleaning performed in previous interventions. [3] The perceptual effect of craquelure turned out to be of the outmost importance in forming a retouching strategy. While relatively small lacunae were distributed over the entire surface of the painting, the brightest area of the composition - depicting dichromatic pavement – had sustained major losses (figure 3). The aim of this paper is to examine the degree of finishing necessary to create an overall balance that will appreciate the condition of the paint layer and the age of the painting. Correspondingly, the applicability of mimetic retouching in such a demanding appearance of the original paint layer will be discussed as well. 2. MATERIALS AND METHODS 2.1. The effect of craquelure on the visual perception of All Saints The pattern of cracks is a visible record of the physical tensions within the structure of the painting [4] dependent upon the choice of materials and methods of construction employed by the artist [5]. The literature explaining the importance and characterization of cracks was reviewed by Keck (1969) and Bucklow (1997). Namely, the first records are due to artificial craquelure created by the art forgers (William Sanderson, Friedlander), while the general descriptions of the shape of the patterns were recorded by Stout (1977). More studious observations are of Marijnissen in judging the authenticity of the artwork (1985), and of Bucklow (1994, 1997, 1998, 1999, 2000) in analysing the association of cracks with the artist’s practice and their perceptual effect on pictorial image. [6] The result of this study made evident that the crack network - although subconsciously filtered out as irrelevant - has a large effect on the apparent tonality, i.e. it visually darkens and flattens the image. According to Bucklow [7], the cracks will have a large effect where they cross contrasting paint passages of the underlying image. Simple contrasting paint areas are used by Santa Croce to depict the floor on the All Saints – the decorative tile pattern was painted with two colours of different values – lighter (white) and darker (orange). The simplicity of the geometrical forms – lacking any figural elements – has contributed even more to the pronounced perception of all irregularities of the paint layer, especially the cracks on the white tiles. However, the contrast between the cracks and the underlying image (the floor) interferes with the perception of the contrasts between the tiles. This leads to the conclusion that the formation of the craquelure has gradually compromised the intention of the artist. Yet, on the other hand, it brings out the role of the craquelure as substantive element for achieving the precise tonality in mimetic retouching. Thus a close inspection of the shape and the characteristics of the craquelure has been made. It was manifest that the direction of the crack lines has approximated right angles typical of age-related cracks. The shape of the cracks is quadrangular - very usual in the paintings from the renaissance period – constituting a fairly fine mesh, with no predominant orientation, composed of vertical Figure 4 • Detail of the original paint layer. Note the size and shape of the crack network. Photo © Sandra Šustić

50 Katarina Alamat Kusjanović | Sandra Šustić and horizontal grooves. Assessment of this system reveals a distribution linked to paint constitution. It occurs predominantly in areas rich in leadwhite, such as the flesh tones and, of course, the tiled floor (figure 4). [8] 2.2. Reconstructing the major loss in underpainting Descriptive data on the preserved paint layer beneath the figures showed that Santa Croce employed a geometrical representation of the floor with square tiles, similar to pavement. [9] The square grids are foreshortened as the lines of the grid get farther away from the viewer. In addition, horizontal lines above the background arches and the lines of the paved floor are parallel to the picture plan. By tracing the lines of the floor around the loss - perpendicular to the picture plane - the vanishing point was easily localized and the set of missing parallel and horizontal lines was set up in underpainting using Winsor & Newton Designers’ Gouache (figure 5). This initial inpainting was made several shades brighter than the original paint layer. White tiles were painted with almost pure white colour in order to retain the maximum intensity of the surface for the upcoming glaze technique. Although the artist used only two colours to depict the floor - white and orange - it was noticed that each preserved tile contains subtle tone gradations within its surface. Thus, along with the basic shape of the tiles, the delicate volume was built as well. This helped to establish the liveliness of the ambience found in the preserved paint layer. 2.3. Emulating the appearance of naturally aged paint in glaze technique In order to achieve the illusion of depth, luminosity and patina, evident on the preserved tiles, the paints agglutinated with Canada balsam - with a refractive index approaching that of an aged oil medium - were chosen for final retouching. To match the colour of the tiles, the pigments such as umber, yellow ochre and blacks were indispensable. The first step was to spread a highly transparent dark glaze over the reconstructed tiles. Due to the relatively rapid evaporation of the solvents used (butanol, ethyl lactate) it was not easy to achieve uniform horizontal strokes. There were undesirable brush marks and uneven glaze accumulation on the surface, hence the same glaze was gently splattered over the surface with a brush. This treatment has gradually softened the edges of the glaze, thereby producing blurred effects of shading. Each tile was treated separately, while others were completely covered, in order to avoid unnecessary splattering of the surrounded area. The most important step in achieving mimetic retouching was to emulate the quadrangular network Figure 5 • The All Saints after underpainting. Photo © Croatian Conservation Institute Figure 6 • Reconstruction of the white tile. Note the artificial craquelure. Photo © Sandra Šustić