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Abstract
A program for the rehabilitation of the Last Supper of the French sculptor Philippe Hodart was started in 2002. The clay images of the Christ and the Apostles, dated 1534, were broken and scattered. The first museum director, António Augusto Gonçalves, recovered most of the set and in 1960 gave the ensemble the deserved highlight despite its deplorable conservation state. The intervention, carried out for more than three years, allowed us to understand several factors related to the creation of the work and to show to the public aspects never revealed before.
The Work The Last Supper by Hodart, made in 1530-34, is composed by 13 figures: “twelve apostles together with the Christ, all in clay, all life-sized figures”. They were grouped around a table with the lamb and all the necessary things for the supper, everything made of clay, very natural and faultless”. The work was received by Friar Brás of Braga, who was in charge of the reformation and the works of the Santa Cruz Monastery of Coimbra, on January 8, 1534 [1, pp. 64]. The Santa Cruz refectory, made by Diogo de Castilho, was composed of a rectangular room, in the middle of which an arch would receive the ensemble: “a beautiful stone arch, where the Chapel called Supper of the Lord is, where the holy Master can be seen seated at the table with the twelve apostles, all figures in relief made with great spirit, and that represent that last supper so well” [1, pp. 78]. The Material The name terracotta derives from the Latin “terra cocta” which means “baked earth”. It designates, in a general way, the clay mixed, worked and fired in kilns, one time only, at a temperature between 900º and 1000º C. A more detailed definition may be the one of a relatively heterogeneous paste, of coarse structure due to the presence of pores and impurities, which constitutes a coloured, porous, opaque and uncoated ceramic body, cold manufactured and consolidated by heat [2, pp 81-82]. The results obtained by X-ray fluorescence and diffraction analysis performed to the sculptures revealed relatively high contents of SiO2, Al2O3 and K2O, as well as the presence of quartz, feldspars, illite/muscovite and traces of mullite. The clay composition is, thus, illite-kaolinite with calcite dispersed in the plastic component and quartz and feldspar in the non-plastic component. With these characteristics, along with the texture of the ceramic material and the geologic setting - the city of Coimbra – it is likely that the clay used came from local sources. The Technique The Making of the Figures The sculptures could not have been modelled at once as they are life-sized figures. Several breaks would have been necessary to allow the clay to dry, acquiring the necessary resistance, in order to progress with the modelling without deformations. The areas in work were probably covered between sessions with humid cloths to keep the clay malleable [3, pp. 23]. Diogo de Macedo [4, pp. 18] states that Hodart had the collaboration of a locksmith, Gabriel Belém, which would have executed the anchor structure for the artist studies. It is common practice to make the internal structure in iron or wood on which the clay is applied according to the figure’s volumes. A wood mallet is used to improve the shape of the structure according to a draft previously made. The apostles’ heads and hands were modelled apart, as proved by the terracotta spike conserved on only one figure’s head, the fact that they are hollow, the conic shape of the fists and the existence of openings in the neck and forearms. The draperies were the last to be modelled, by overlapping thin clay layers, as well as the hair, nails and costume ornaments, using different instruments depending on the intended texture. The carnation was subject to a more careful work; engobe was applied to smooth the face imperfections and to homogenise the surface, giving it an even and less porous aspect. Hollowing and sectioning The figures were hollowed to reduce the thickness of the walls in order to minimize the risk of facture. The marks of the instruments used for that purpose are still visible. In general, the thickness is constant to ensure that the contraction experienced during drying and firing is uniform [5, pp.28]. On the posterior side, some pieces have small sections – ‘lids’ - probably used for the hollowing process, facilitating the drying of the figures and the access to their interior after firing [5, pp. 28]. In order to avoid cracks Hodart left ventilation openings – ‘vents’ - of different shapes, often localised on the back of the head. These allowed the water vapours and gases from the combustion of organic matter to escape during drying and firing, avoiding the pieces to come apart [5, pp.28; 6, pp.31]. We believe that the sectioning of the figures was made after the hollowing when the clay was firm but still humid. Hodart would have sectioned the pieces on their harder areas according to vertical, horizontal and oblique planes, dividing them in two or three sections. Although some of them present small differences in size, which may be due to different firing or temperature variation inside the kiln [7, pp.71], most figures fit perfectly between them. Drying After the figures were hollowed and sectioned, the individual sections were left to dry out prior to firing, a process that was slow in order to avoid deformation, fissuration or even fracture [7, pp. 44] and to allow constant moisture evaporation. For this, the sculptor would have to cover the figures with a cloth for one or two weeks and then uncover them gradually. As the drying period depends on the clay thickness [6, pp. 33], it is considered that each apostle figure took between one and two months to dry. However, the figures drying at room temperature would not have loosened completely their moisture. This would only happen in the kiln at a temperature of 100º C, when atmospheric water evaporates. The firing The sculptor probably used a wood kiln equipped with an oven chamber and a chimney for hot exhaust gases, allowing the flames to move upwards and the hot gases to circulate between the sections that were not subjected to direct action of the flames. The sections’ dimensions allow us to state that the oven chamber had approximately 1 meter height and at least 80 centimetres width and depth. Considering the 39 months period that took Hodart to complete the work, it is likely that he used one single kiln. As the sculptor would finish a figure, that is modelling, hollowing and sectioning it, he would fire it, each section at a time. The mineralogic composition revealed several crystalline phases, namely illite/muscovite inherited from the raw materials and mullite formed during the firing, indicating that it was a slow process at a maximum temperature of 950º C. The polychromy Some sculptures present traces of polychromy and white preparation on the most protected areas of the figures, namely within or between the folds and under the arms or collars. Optical microscopy revealed that in general there is a yellow/brown layer applied immediately over the support and a white layer, probably preparatory, applied over the previous one, followed by two or three more overlayers. X-ray micro diffraction and microchemical analysis identified the pigments used: Prussian blue, lead white, charcoal, yellow ochre and vermilion on the most recent polychromy, and azurite, lead white and vermilion on the most likely original polichromy. Micro-fourier Transform Infrared Spectroscopy identified linseed oil, skin glue, proteins and starch as binders. Conservation State By decree of July 6, 1865 the Ministry of Public Works granted the Santa Cruz refectory to host the Coimbra Artists Association. When the Apostles’ Chapel was transformed into the association’s reading and meeting room, the figures’ arms were broken into pieces and used as waste material [1, pp. 86]. According to Aarão Lacerda, “the composition was hammered down to build a platform over which, in a shabby pedestal, the figure of D. Fernando was placed” [8, pp. 90]. Fernando de Pamplona [8, pp. 90] refers that the figures were taken out of the monks’ intimacy and tossed away carelessly to deposit rooms where they got broken and parts of them were even buried. In 1866, Possidónio Narciso da Silva, president of Lisbon’s Architects and Archaeologists Association, visited the place where the Supper was located and ordered to saw off the heads and the arms which he took back to the association, together with other objects. In 1890, António Augusto Gonçalves saved the Apostles from total destruction. Unaware of their origin, he recovered some heads, paying a guard from the Artists Association to reveal him where they were kept [9, pp. 230]. As part of Coimbra’s town council, he recovered from rubble what was left of the ensemble and restore it as he could. Table 1 shows the figures’ main conservation problems.
History and Methodology of Restoration
The restoration intervention had two main objectives: on the one hand, to restore the structural elements, with the main objective to provide both physical and chemical integrity and stability to the set; and on the other hand, to restore the formal and figurative values, where the reconstitution of the formal values of some figures was necessary for a good reading of the work. Restoration of the Structural Aspects Salt extraction Although this treatment was not a priority for all the figures, it was chosen to be performed first as it is easier to desalinate the whole piece than several fragments. The removal was made by osmosis applying patches of paper pulp with weekly conductivity measurements (figure 3). Disassembly The next stage was the disassembling of the figures and the removal of the wooden bases as they were unaesthetic, attacked by xylophagous insects and rotten, and unable to perform their function (figure 4). The materials that attached the figures onto their bases - gypsum, sisal and cement - were removed mechanically and the figures were disassembled in individual sections, previously identified. Incorrectly glued fragments were also separated, allowing a formal reading of the shapes.
Figure 1. The sculptural ensemble "Last Supper" exposed at MNMC.
Figure 2. Apostles’ ancient wooden bases. Figure 3. During treatment; the extraction of salts. Figure 4. Apostle upper body already separated from its legs. Verification of the metallic elements Iron elements were used, probably to unite sections or to reinforce fragile areas. Their removal was not difficult as they were oxidised and unstable, unable to fulfil a bonding function and jeopardising the stability of the terracotta. However, it was sometimes required to drill holes around them in order to use pliers for their extraction (figure 5). Removal of the old filling materials All gypsum and cement fillings were mechanically removed as they were contaminating the support with salts and were disturbing the formal reading, overlapping the original surface (figure 6). Occasionally, when the removal would extremely weaken the support or when the adhesion of the cement was too strong, it was decided to remove as much as possible of the material but without reaching the terracotta surface. Polychrome consolidation and fixation It was found necessary to consolidate some areas and terracotta fragments due to their lack of cohesion and to fixate the traces of polychromy and preparation layer. Both procedures were performed by brushing, with an acrylic resin dispersion at 10% and 15% in organic solvent (figure 7). Cleaning All the sections and fragments were mechanically cleaned with soft hair brushes and a controlled suction vacuum to remove the surface dirt with low adhesion. The materials with stronger adhesion - glues, plaster and mortars - were removed on a later phase with scalpels and chisels. Chemical cleaning was performed selectively, reaching an average cleaning level and preserving all the white preparation and polychromy traces. The cleaning allowed the comparison between the fragments, leading to the conclusion that there were elements with different visual quality, and returned the pieces their decorative richness once many of the motifs were hidden under the dirt.
Parts Identification
Figure 5. Extraction of the metallic elements.
Figure 6. Separation process of the head from the apostle's body. Figure 7. Traces of blue polychromy. Figure 8. The new metallic base structure with three adjustable positions. A structure in aluminium composed by one or two parallel profiles and a third perpendicular one was designed for each of the figures. The first structure was used to attach the heads to the body (figure 9) and the second to attach two sections between them (figure 10). In this case, one of the two parallel profiles was placed on the respective section and the union was made with screws, facilitating the assembly and disassembly of the parts. The profiles are fixed on the interior of the figures with a 30% solution of acrylic resin in acetone and 25 microns stone powder. Although the principles adopted for the structures are identical in all figures, each of them presents a particular shape that adjusts to their volume and ensures the stability of the ensemble. Aluminium was chosen due to its good performance to oxidation, its lightweight and resistance and also its availability on the market in a great variety of profiles, allowing for a wide variety of solutions. For specific cases special solutions were adopted (figure 9-14): a) When jointing of sections was not possible due to the lack of access to the interior of the part (figure 11); b) For the almost total reconstitution of the elements and for the fixation of the lids (figure 12); c) To allow the assembly and exhibit of the parts with incomplete sections (figure 13 and 14).
Figure 9. Structure designed to attach the head to the body.
Figure 10. Structure designed to attach two different sections of the body. Figure 11. Structure designed to attach the sections when lacking access to the interior. Figure 12. Structure designed to the almost complete reconstitution of the elements and lids fixation. Figures 13 and 14. Structure designed to facilitate the assembly and exhibition of sculpture with incomplete sections. Jointing Whenever possible, the fragments were joint with acrylic resin (30%) in a first phase and later with epoxy resin. Two types of resin were used due to the fact that in the initial phase the fragments required a temporary gluing, as other fragments could be later found to complete the surface. A preliminary jointing ensured the possibility of easy removal whenever required. When it was considered impossible to adjoin another fragment and the acrylic resin was not sufficient to ensure the stability of the fragments, this was removed and a new jointing was performed with epoxy resin. The jointing of structural fragments, or of the parts where contact points were few, required the application of brass spikes. The process was assisted with diverse systems such as cases, sand pads, duct tape, plastic or fabric tape, clips, etc., adapted to the shape of the fragments and to their resistance. Filling The filling of the superficial cracks and fissures was performed with a vinyl-based paste (DAS), which is non-hygroscopic, resistant and very ductile, to which demineralised water was added to facilitate the modelling. In deeper, structural areas or where a mechanical resistance was sought, the filling was performed with acrylic resin at 30% in organic solvent (acetone), using as filler limestone powder of 25 microns. Conservation of the Formal Aspects Once the physical and chemical stability of the ensemble was ensured, the next objective was to return its formal reading by restoring the continuity of the surface and its aesthetic values. In order to allow a correct formal reading of the ensemble it was necessary to restore some figurative parts as several lacunas were disruption points in the composition. The adapted criterion was to differentiate the interventions performed, not deceiving the observer but warning him/her of our aesthetic concern, that of enabling the public to enjoy the ensemble. Reconstitutions The reconstitutions were made with a mixture of stone powder of 25 microns bonded with acrylic resin (30%) dissolved in organic solvent (acetone) at a level lower than the original. In situations where the areas to fill were large, it was necessary to use as filling Leca®, a very light and resistant spherical inert material. In places where it was not possible to apply the filling material, it was necessary to insert a polyethylene net attached to the terracotta with epoxy resin. The areas that would come in contact with the filling material were isolated with acrylic resin (3%) in organic solvent (xylene). The final layer was applied with vinyl paste DAS modelled in the same way as the original. Chromatic reintegration According to the principle of authenticity, as set out in the Nara Document (UNESCO, 1994), a difference between the original materials and those used in the present intervention was made. Indeed, the combination of both is easily perceptible by their different tones. The main objective was to provide a good reading of the figures and decorative motifs, while ensuring that the reintegration was discrete and in harmony with the ensemble. Acknowledgments The present work was carried out by the team of the National Museum Machado de Castro with the collaboration of contracted professionals. We express our sincere thanks to Ana Alcoforado, António Ferro, Ausinda Félix, Carlos Santos, Cecília Beirão, Cláudia Felix, Conceição Reis, Dulce Gonçalves, João Nora, João Pocinho, Narcisa Ferreira and Nazaré Neves.
Drawings by João Pocinho
References [1] J.M. Teixeira de Carvalho, A Cerâmica Coimbrã no século XVI, Imprensa da Universidade de Coimbra, 1921
[3] I. da Piedade e Vasconcellos, Padre, Artefactos, Symmetriacos e Geometricos, Lisbon, Joseph Antonio da Silva, 1733, pp. 48-51
[8] J. M. Teixeira de Carvalho, "Museus provinciais" Arte e Arqueologia, Imprensa da Universidade de Coimbra, Coimbra, 1925, pp. 89-91
[9] F. de Pamplona, Dicionário de pintores e escultores portugueses, volume IV, Livraria Civilização Editora, 4ª Edição, 2000
About the author Catarina Gersão de Alarcão Conservator-restorer of sculpture National Museum Machado de Castro, Coimbra Contact: mnmc.catarinaalarcao@imc-ip.pt,catarinaalarcao@gmail.com Catarina Alarcão graduated in Conservation-Restoration from the New University of Lisbon. She than received a grant from the Ministry of Culture in 1997 and undertook the Corso di Perfezionamento sui restauro dei materialli lapidei in the Istituto Centrale per il Restauro in Rome for 11 months. Since 1998 she works at the National Museum Machado de Castro being the responsible of the workshop of sculpture conservation-restoration. She coordinates internships and training programs, and she designed and coordinated the exhibitions “Esculturas em diálogo” and “Conhecer é conservar” that took place in the same museum. She published “Introdução ao estudo material e à conservação da escultura em pedra e em madeira” [Introduction to material study and to the conservation of sculpture in stone and wood] (December 2002) and has presented several communications of projects developed in the museum and from her private practice.
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