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MAGAZINE Archive Issue 13 The Conservation of the Altar Frontal from the Church of Nossa Senhora da Piedade de Santarém
MAGAZINE Archive Issue 13 The Conservation of the Altar Frontal from the Church of Nossa Senhora da Piedade de Santarém
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Abstract
The present article describes the conservation treatment of a 17th-18th century altar frontal from the church of Nossa Senhora da Piedade in Santarém. The altar frontal is decorated by a floral decoration in metallic thread on a beige silk damask fabric. The conservation-restoration treatment consisted mainly in mechanical and wet cleaning and physical stabilization which improved considerably its mechanical stability and aesthetics. A new exhibiting system was also implemented along with preventive conservation measures. The altar frontal is part of an extensive religious textile collection which has already been catalogued. This intervention shows a beneficial collaboration between the responsible for religious heritage and accredited conservation professionals in order to preserve objects of art that are so often threatened by lack of economic resources or simply by ignorance. Introduction The Church of Nossa Senhora da Piedade in Santarém was selected in 2006 as the Pilot Church of the Diocese of Santarém, under the “Safe Church - Open Church” Project, developed by the Institute of Police and Criminal Sciences. This project is focused on the implementation of actions at the level of safety and conservation for the protection of churches and its heritage, both movable and immovable. Among other measures, the inventory of the church movable assets was carried out, which allowed to quantify and to assess its technical quality and importance. It was also possible to assess the overall conservation state of the collections and to set up priorities for its conservation. The inventory also allowed to establish the predominance of textile objects in comparison to other object categories, namely about 300 objects from 700 (figure 1) [1]. The textiles collection is mostly composed of items from the 17th-20th centuries, mainly with vegetal decoration but presenting several typologies, techniques and materials [2]. While most of the items have a high artistic, historical or cultural quality, there are others that have a lower technical and artistic relevance. However, these are important to characterise the local production and for the local identity [1]. Thus, all the items were subject either to conservation-restoration treatment or to preventive conservation. This project of inventory and preservation of the church heritage was partially published as a catalogue which includes a series of specialised collaborations [1, 2]. This publication contains, among others, a chapter dedicated to the definition, conservation and preservation of the textiles, including the altar frontal in study. It is expected that this publication, along with other actions, will help to raise awareness among the responsibles of the other churches as well as of the general population in order to allow a better collaboration with accredited conservators. The altar frontal is an example of the assets that were treated. Its physical condition was greatly improved and stabilized by means of a methodology designed according to the current ethical criteria. A new exhibiting system was designed for its future preservation and display. At the same time, preventive conservation measures were recommended which can also be extrapolated to the entire collection with appropriate adaptations. Altar Frontal Technique and decoration Altar fronts are objects that have the purpose of decorating religious spaces, namely altars. They are also known as antependium and have several types of decoration depending on their manufacturing period. Nevertheless, they are always rich in decoration and it was one of the most prominent ornaments in the altar1 [3]. The present altar frontal originally belonged to the Convent of Donnas2 , according to the inscription found on a label sewn on the back (figure 2), and it was one of the pieces later taken to the church of Nossa Senhora da Piedade in Santarém after the extinction of the convent, in the late 19th century. The frontal has a rectangular shape and measures 280x100 cm (figure 3). It is made with beige damask3 fabric with decorations sewn with laminated golden-gilt thread (flowered4 ) and elements of lacework (galloons and metallic fringe) applied on a fabric support of brown taffeta which exceeded the frontal upper limit at about 10 cm and the laterals at about 4 cm.
Figure 1. Distribution of the movable heritage of the Church of Nossa Senhora da Piedade, where the textile category is predominant.
Figure 2. Identification tag with the origin of the altar frontal. Figure 3. General image of the frontal before the intervention (photomontage). - 5 panels of the field and 5 frontal panels, with 50 cm wide each (distance between the lateral selvedges); - 4 panels of smaller width, located on the frontal and field lateral edges, which may result in additions or cuts of the existing fields.
In the frontal area, each panel is divided in the center by galloon application, in a total of 10 small panels of 25 cm wide. The galloons sewn with metallic thread divide the different panels. The upper and lateral perimeter of the object is finished by two overlapped strips of beige gallon.
Concerning the decoration, the damask fabric presents vegetal motifs developed symmetrically around an axis of longitudinal symmetry. The drawing contains highlighted flowers and leafs surrounded by decorations made by laminated golden-gilt thread in the espolinado technique, drawing flower laces and garlanded strings. A vertical selvedge which allowed to verify the decorative sequence was also found concluding that each panel of the field corresponds to a module of the decorative pattern. It should be noted that it was the combination of the materials and techniques that gave the shine and splendour to the frontal. When beige silk is used, it is causing a highlight reflection with the damask fabric. Part of the decoration is made of satin, with smoother and more reflective surface, contrasting with the taffeta areas. The lacework and the metallic decoration have also a strong contribution to the overall shine. In this type of damask decoration the ornamental motifs of large dimension from the 17th century evolved in the 18th century to designs increasingly more detailed. Thus, the middle size of the frontal motifs suggests that it belongs to a transition period. In addition, the used of metallic thread and the comparison with other frontals already dated and that are stylistically similar, make it probable that the frontal dates from the 17th century or early 18th century. Identification of materials The morphology of the fibers was analyzed by optical microscopy through the observation of the longitudinal cross-sections of the fibres5 in transmitted light (figure 4). The presence of silk on the support damask fabric, on the frontal edge galloon and in the core of the laminated thread of the decoration and lacework was confirmed, once the interior of the analysed fibres is smooth which is characteristic of the silk fibers Bombix Mori [5]. The same analysis was performed to the support fabric which revealed the presence of fibres with cellulosic constitution, most probably linen6 according to the presence of nodules [5]. However, this last fibre was impossible to identify. Concerning the laminated thread (figure 5), it was also not possibly to identify the component materials. However, the characteristic golden shine suggests the presence of gold. Given the oxidation of the most exposed laminated thread, where in some areas led to its browning, it is likely that the metal should be either a metal such as Cu or Ag or a gold-plated alloy, once the presence of pure gold itself wouldn’t led to such strong darkening7 and since it is the noblest element used in the production of metal decorations applied in textiles [6]. Furthermore, the use of metallic threads made of silver plated with gold (15th-17th centuries) and golden copper threads (since the 17th century) reinforce the hypothesis of the golden alloy thread from the 17th-18th century [7]. The material analysis verified the common use of more noble fibres, such as silk and laminated thread, on the visible decorations and cheaper fibres on the support fabrics. The application of laminated thread was reserved, especially, to the front side of the damask fabric. This analysis was also important as it helped in the selection of the materials to be used in the conservation-restoration treatment, allowing thus to select the most compatible materials with the original ones.
Figure 4 a and b. Optical microscopy images by transmitted light from the longitudinal cross-section of the fibres.
Figure 4a shows silk fibres, characteristically with the interior smooth while figure 4b shows a typical image of a cellulosic fibre, most probably linen due the presence of nodules on the interior. Figure 5. Optical microscopy image by reflected light from a laminated thread, where the S torsion of the metal around the fiber core can be seen. Assessment of the conservation problems In the analysis of the conservation state of a textile object it is important identify the degradation of the object but also the degradation agents that induce it. Thus, determining the problem source it will be easier to develop and to implement the solutions. The frontal present problems mainly at a physical and mechanical level, that contribute to its weakness and that also affect its aesthetic reading. The major forms of degradation (figure 6) can be enumerated as follows: - Loss of textile material by the presence of tears (25% loss of warp threads) and lacunas (10% loss of warp and weft threads); - Loss of metal by the presence of lacunas (5%) and detached metallic threads (30-35%); - Wrinkles, creases and strains (10%); - Oxidation and darkening of the metallic surface (80% of the areas with metallic thread); - Yellowing and darkening of the silk fibres (90%); - Presence of dirt as agent of degradation, in the form of solid particles (90%), damp stains (20%), paint stains (3%) and rust lacunas or stains (5%, especially on the support fabric); The tears, caused mainly due to the loss of warp threads, are located mostly in the central panels. Furthermore, there are also some tears in the areas under the fringe, here being caused by the local galloon anchors in the fabric which induced tensions, and abrasion in the fringe of the silk fabric. The appearance of gaps is also considerable in the in the lower panels, near the lower end which is also more favourable to wear, and especially in the first panel. In these same areas there are more formal alterations such as wrinkles due to the weight of the fabric and creases due to the incorrect storage since the frontal was often folded in the same areas, bearing the weight of other parts. The areas with detached laminated thread are mainly concentrated in the central area of the panels and at the bottom, mostly due to the use, handling and abrasion of the surface. The border areas between the fabric and the decoration with laminated thread are intrinsically weaker areas as they are made from two different materials – fibre and metal – that react differently to the relative humidity and temperature. Since environmental conditions were not controlled, the frontal was subjected continuously to cycles of swelling and shrinking leading to the weakening of those union areas and to the detachment of many laminated threads. Aesthetically, the frontal is affected by tears, lacunas and detached laminated threads revealing the underlying support fabric of darker colour. Furthermore, the oxidation and darkening of the metallic surfaces led to the loss of its characteristic golden glow. This alteration is due to the inherent natural degradation of the metal and it occurs especially in the most exposed metallic surfaces. This has contributed to its abrasion and humidity absorption, and to oxidizing agents, such as some pollutants and oxygen itself, since the metallic surfaces located in the most protected areas in the fringe still maintain a strong golden shine. The silk fibres have a natural yellowing caused by oxidation and ageing due to ultraviolet. Dirt, dust, sand and soot in particular, were more or less adherent to the fibres and its interstices and according to its nature it was difficult to remove. The presence of fat particles, like wax, and several types of stains, including ink, that adhered firmly to the fibres was also observed. Regardless of the nature of the dirt, it induced degradation in medium to long term. Furthermore, dirt can cause abrasion, loss of flexibility, irreversible colour change, increased acidity and occasionally total destruction of the fibres [6]. Conclusions of the conservation state The main conservation problems of the frontal are the lacunas and tearing which prevent the normal handling of the object and compromise its stability. These degradations have a negative influence on the aesthetic reading of the frontal. Considering all these problems, the conservation state of the frontal should be qualified as poor but given that the fibres and galloons are relatively resistant, it can be considered reasonable. The treatment will consist largely in the stabilisation of the vulnerable and detached areas and cleaning. The aesthetic improvement is mainly a direct consequence of physical and chemical treatments. Conservation and Restoration Intervention Considering the nature of the materials and the diagnosis of the conservation problems, the intervention was divided into several stages according to conservation principles and intervention criteria currently established. Disassembly of the frontal This was an essential step for the continuation of the following treatments, namely cleaning, washing, and lacuna stabilisation. The disassembly was performed by separating the various components: the support fabric of the several panels, the panels, the fringe and the galloons. All items were numbered and marked, and their original location was identified for future reference during the assembly operation. Mechanical Cleaning Beyond fabric’s evident loss of brightness, the observation under magnification revealed small particles of dirt (dust and other solid substances) and drops of wax that could be removed by mechanical means. The cleaning procedure was performed using a vacuum with thin nozzles, with controlled suction, and with the help of tweezers and scalpels to remove the wax drops in the fabric, lacework and support, on both sides. The most vulnerable areas, those with metallic thread and tearings, were protected by tulle during this process. The result was a considerable removal of solid dirt particles which were less attached to the fibre’s surface as seen in the filter (figure 7), as well as several lines that originally sewed the frontal. Wet Cleaning Although mechanical cleaning removed a large amount of dirt, there were still certain types of stains more closely linked to the fibres and to the metallic surfaces, likely to be removed only by washing. Washing is an irreversible operation and, as such, it should be carefully considered. The frontal presents on the support fabric one single type of fibres – silk – that, despite the reported problems, show favourable mobility and endurance. At the same time, the damask is a composite material with the presence of additional wefts of laminated thread which may cause a problem once the actual cleaning methods of metals can degrade the adjacent fibres [6]. The fibres and the laminated thread were capable to withstand a soft cleaning which consisted in the application of distilled water8 and a neutral and anionic surfactant9. A test was performed on the smallest element of the ensemble, in the frontal upper right corner, which showed no alteration or risk for the metallic elements. The dimensions of the elements were recorded before and placed between tulle for easier handling and protection during the washing. A natural sponge was also occasionally used. After washing, the water excess was removed with white Turkish towels and flattened with weights. After this procedure, there was a considerable increase in the brightness of the silk fibres, despite their yellowing and ageing, as well as some metallic sheen. The ink stains and those caused by humidity were reduced. The wrinkles and creases were successfully removed and the fibres in the areas of tears and lacunas were properly aligned. It was, thus, a fundamental step to improve the conservation state of the frontal. Consolidation by needlepoint This phase of the treatment was fundamental to return the mechanic stability to the object as it allowed to stabilise the areas with tears and lacunas and to consolidate the detached metallic elements. Although mechanic, this intervention it is completely reversible which brings significant advantages in terms of conservation. To this end, we resorted to the application of partial supports of natural silk10, fully compatible in material, density, malleability and colour with the original material. Each fabric support covered a field panel and the respective frontal. The stabilization of the tearings and lacunas and fixation of the detached laminated thread was performed using needlepoint with natural silk thread making perpendicular lines to the weft and regular spacing of approximately 5 mm. The number of stitches was the minimum required to the stabilization of degraded areas. In the areas with laminated threads the spacing was bigger (8-10 mm) in order not to be visible. At the end, some fixation points were performed to fix the silk support uniformly across the panels at regular space. After consolidation, a partial facing of nylon tulle was also applied for protection in the lower areas of the panels that presented lacunas (figure 8). Partial consolidation was performed in the galloon of contour and support fabric using, in this last case, partial supports of flax fibres. Reassembly of the frontal After the intervention, the frontal was reassembled on its position taking into consideration the order and original location of every individual item (panels, galloons and fringe). During the reassembly, the same stitches and lines of natural fibres were used (figure 9).
Figure 6. Schematic representation of the main conservation problems of the frontal: - lacunas and tears; - lacunas and detached metallic thread, - wrinkles and creases; – wax drops.
Figure 7. Dirt that was retained in the filters of white fabric, during the vacuuming of the field panel and the frontal. Figure 8. Detail of the area protected by tulle, before and after the intervention. Figure 9. Detail of some areas from the frontal with tears, lacunas and detached metallic thread, before (a, c and e) and after (b, d, and f) the intervention. Figure 10. Dimensions (cm) of the frame and application points of the Velcro® for fixing the frontal. Figure 11. Exhibition of the frontal mounted on the frame at the church of Nossa Senhora da Conceição in the Cathedral during the Easter Triduum. A barrier was placed in front of the altar for further protection. Exposure and use Religious objects involve a symbolic nature for the use in the church for which they were created. Whenever the conservation state of the object allows it, it makes perfect sense to create systems for its display and use. The usual fixation method of the frontal to the altar was using nails, pins and even adhesive tape which caused damage to the frontal but also to the altar. In order to prevent further damage and to improve he display, the implementation of a new exhibition system was proposed. Textiles are fragile, sensitive to light and other degradation agents, and therefore the exposure time should be limited to short periods and resting periods should be scheduled. Thus, a removable display of easy assembly and transport in case of emergency was designed. A system was proposed that consisted in the construction of a wooden frame [8], of the same dimensions as the frontal (figure 10), which would match the bars and beams according to the distribution of the galloons, with the application of strips of Velcro® on all its extension. On the backside, a “lining” of washed cotton fabric was attached by needlepoint to the support fabric. Afterwards, some strips of Velcro® were also sewn to that fabric in the area of the gallons, which it is more resistant, in order to apply Velcro® in the frame as well. The distribution of these strips was planned to obtain a balanced weight distribution, avoiding thus unnecessary stresses. Besides the main advantage of adequate exhibition, the frame presents other relevant advantages such as: the physical separation of the frontal from the altar and its reduced weight, facilitating thus its transport, even in case of emergency; the suspension of the frontal at some distance from the ground which will avoid further degradation of the lower areas and the accumulation of dirt; the possibility of using the frame with other similar frontals and its use in other places than the church. It is also advisable to protect the frontal during the exhibition in order to avoid the deposition of dirt and to prevent damage from visitors. The most effective protection would be to place in front of the altar an acrylic sheet with the same dimensions and preferably with UV protection, or at least a physical barrier to keep visitors at some distance during the ceremonies (figure 11). It is known that light is one of the main degradation factors of textiles, with cumulative effects and causing irreversible damages to the fibres. Although churches are usually maintained in twilight, it is advisable to reduce the light exposure at the maximum and take appropriate preventive measures11. It is also strongly advised to expose the object for no more than 3 or 4 months, after which the object should be kept without light over a period of a few months. Another important aspect is that all the handling should be made with gloves and by more than one person due to its large dimensions. At the moment, the frontal is only used in the festive liturgical celebrations, namely on Easter and Christmas, for a maximum period of one month. Packaging and storage Prior to the inventory of the textile collection of the Church of Piedade, the entire collection of about 300 objects was kept inside two wood chests in the church, being of a considerable volume for such a small space. Due to economic and space constraints, it was not possible to built a space with appropriated conditions for the conservation of the collection. Nevertheless, during the inventory it was possible to improve the storage conditions by implementing shelves to avoid the excessive overlapping, and rolls of silk paper in the folds to prevent the formation of creases. The financial resources also did not allow the acquisition of special storage materials, known to the stable and chemically inert [9]. A satisfactory low cost solution was implemented by the use of cotton cloth unbleached and previously washed, and white silk paper (ideally acid free). These materials should be washed and substituted on a regular basis (annually). Concerning the frontal, and given its dimensions, it was decided to store it rolled12 up with the front part, which is more voluminous, on the outside. The rolling was done on a tube longer than the frontal and with a diameter larger than 20 cm [10]. The roll should not be too tight and it should be placed with an interface of other material to protect the surface of the object, and fixing the fabric with strips of tissue or Velcro®. On this case, previously washed and unbleached cotton fabric and a sealed cardboard tube were used as interface materials. The pieces were also properly labelled in a visible area for future reference. The environmental parameters from storage and exhibition areas should also be controlled in order to achieve values with minimal oscillations within relative humidity = 50 ± 5% and temperature = 20 ± 5 º C [6]. Conclusions and Future Work
The conservation-restoration intervention here reported was the starting point for the intervention on other textile items from the same collection as well as from other parishes in the Diocese of Santarém.
The current Diocesan Commission for the Church Cultural Heritage from Santarém is the responsible for establishing the link between the churches and accredited professionals, contributing thus to increase the awareness of the heritage holders, and promoting a closer coordination and collaboration to their real needs. Thus, joint efforts have already begun to help safeguard the assets and in particular of the religious textiles. Although the starting point has often few resources, it is our objective to overcome these initial limitations in order to solve new challenges and develop solutions for the preservation of this important heritage. The adaptation of theoretical concepts to reality is a continuous but essential challenge as the conservation-restoration is feasible within the search of balance between the real and the ideal. Notes 1 This ornament has its origin in the towel that covered the altar table towards the floor, on the front and sides. With time, to be more practical, this towel was eventually cut at the corners and its front border part became an independent vestment [3]. 2 Convent of São Domingos das Donas was the feminine side of the Dominican Order. It started in the 13th century and it was extinct in the late 19th century [2]. 3 Damascus is a type of fabric that, on its primitive form, consisted of a background effect and a drawing effect given by the warp and weft of a single needlepoint, having the particularity of being reversible [11]. 4 Espolinado is a term used to describe a drawing effect formed by a weft that limits its work to the width of its motifs [11]. 5 Optical microscope Bresser Biolux AL. The samples were prepared on slides using glycerine. 6 The flax fibres are characterised by hexagonal cross sections [5]. In order to confirm the identification a transversal cross section of the fibre would be required. This was not performed due to the lack of the necessary resources. 7 Deposits of dirt, grease, lime deposits or even corrosion products from the metallic alloy can be found over gold but are not gold corrosion [6]. 8 Water is the most polar solvent that is known. It has the capacity to dissolve organic and inorganic polar dirt, to dissolve the acidic degradation products of the fibers, and to serve as plasticizer agent of polymers, improving their flexibility and allowing the removal of deformations [6]. 9 Tergitol NP9 (Nonylphenol Ethoxylate) was used to dissolve polar and non polar dirt [6]. Technical sheet available at: http://www.dow.com/surfactants/products/nonylph.htm (accessed on 17/05/2009). 10 The use of support fabric of compatible material to the original is an assurance that the new fabric will have a degradation pattern similar to that of the original silk, and will react similarly to the environmental factors. 11 The current maximum illumination value is 50 lux and in case the UV radiation exceeds 75 µW/lm UV filters should be used in both lamps and windows [6]. 12 Ideally, the frontal should be stored flattened in the interior of a box or shelf. However, due to the space constraints, such thing was not possible. References [1] E. Neves and M. Covas, “Igreja Piloto: Segurança, Conservação Preventiva e Inventário”, in E. Neves and J. Ganhão (coord.), Igreja de Nossa Senhora da Piedade, Santarém – História e Património, Diocese de Santarém, Santarém, 2008, pp. 52-57 [2] E. Armindo, “A Colecção Têxtil da Igreja de Nossa Sra. da Piedade”, in E. Neves and J. Ganhão (coord.), Igreja de Nossa Senhora da Piedade, Santarém – História e Património, Diocese de Santarém, Santarém, 2008, pp. 122-129 [3] T. Alarcão and J. A. S. Carvalho, Imagens em Paramentos Bordados. Séculos XIV a XVI, Instituto Português de Museus, Lisboa, 1993 [4] T. Alarcão and P. Tomás, “A arte dos têxteis: os paramentos da Santa Casa da Misericórdia”, in J. Fonseca (coord.), Misericórdia de Montemor-o-Novo – História e Património, Santa Casa da Misericórdia de Montemor-o- Novo, Montemor-o-Novo, 2008 [5] C. A. Farnfield et al., Identification of Textile Materials, The Textile Institute, Manchester, 1985 [6] A. Tímár-Balázsy and D. Eastop, Chemical Principles of Textile Conservation, Butterworth-Heinemann, London, 1998 [7] P. M. Tomaz, “Estudo e Tratamento de uma Casula do Museu Nacional de Arte Antiga”, Conservar Património 1, 2005, pp. 55-62 [8] C. Arruda and M. F. Godinho, “Trabalho de conservação e restauro de têxteis do Mosteiro de Santa Maria de Almoster”, Revista Estudos 4, 2003, pp. 78-80 [9] J. Tétreault, “Display Materials: The Good, The Bad and The Ugly”, in J. Sarge (ed.), Exhibitions and Conservation. Preprints of the Conference held at The Royal College of Physicans, Edinburg, The Scottish Society for Conservation & Restoration (SSCR), 1994, pp. 79-87 [10] J. Robinson and T. Pardoe, An Illustrated Guide to the Care of Costume and Textile Collections, Scottish Museums Council, 2000, available online at URL [pdf] (last visited on 17/05/2009) [11] Centre International d’Étude des Textiles Anciens, Vocabulário Português de Técnica Têxtil, C.I.E.T.A., Lyon, 1976
About the author
Eva Armindo
Conservator-restorer
Contact: eva.armindo@gmail.com Eva Armindo is a textile conservator-restorer. She has a Bachelor in Conservation and Resto-ration from the New University of Lisbon. She has worked as freelancer for a series of museums, religious and governmental institutions and at the moment she works, also as freelancer, at the Institute of Museums and Conservation (IMC IP.). She has published in national and international publications among which the latest at the ICOM-CC 2008
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