The conservation-restoration in technical plaster sculpture storage of the Faculty of Fine Arts – University of Lisbon
Marta Frade
Universidade de Lisboa, Faculdade de Belas-Artes, Centro de Investigação e Estudos em Belas-Artes, CIEBA. Largo da Academia Nacional de Belas-Artes, 1249-058 Lisboa, Portugal,
Marta Frade (PT) began her training at the Professional School of Heritage Recovery in Sintra in 1997, where she cultivated her interest in the heritage executed in plaster. This material proved to be of the utmost importance in her academic career. She completed her degree in Conservation and Restoration at the Polytechnic Institute of Tomar in 2005. Since 2011 she teaches as an Invited Assistant Professor of the Faculty of Fine Arts of the University of Lisbon and finished her PhD in Conservation and Restoration of plaster sculpture in 2018.
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The1 Collection – understanding preservation

(…) the place where the cultural objects incorporated in the collection are preserved when, for various reasons, they are not exhibited, can and should function in a complementary way, making study collections available, at any time. (Carvalho, Amaral, Sousa, and Tissot 2007)

The building that houses the plaster collection of the Faculty of Fine Arts of University of Lisbon (fig.1) was once the convent of São Francisco da Cidade.

The technical sculpture collection constitutes a place of memory and knowledge while keeping in itself traces from moments of our cultural and patrimonial history. It is a space that, through plaster, chronologically crosses different periods, styles, and typologies gathered in one space, experiencing the evolution of teaching through stories, lives and artists. Stories that travel through the experiences of pensioners and the shipment of their work to Portugal. This is a collection that connects countries as well as cultures of an expanding Europe.

In addition to the preventive conservation actions and activities developed in the sculptural collection, we recently returned to the ornamental sculpture collection of the Faculty of Fine Arts, University of Lisbon. This collection used to be set aside in a temporary warehouse (the one from the National Museum of Natural History) that, however, did not meet the minimum conservation conditions. Despite not comprising all the ideal conditions, the Faculty’s technical collection already holds a few considerations in its management and preservation.

Figure 1 - The plaster cast storage of the Faculty of Fine Arts of University of Lisbon

In the nineteenth century several plaster collections was founded due to the proliferation of copies by all academies of Fine Arts and the existence of private collections. In the period of academism, copying was an integral part of teaching a practice that later faded and vanished during modernism, ceasing from being a primordial matter. Because of this the plaster collections were gradually being devalued.

It is a historical heritage, “a fund aimed at allowing its usage to a community expanded to planetary dimensions and constituted by the continuous accumulation of a range of objects that congregate their past common belonging: artwork and masterpieces of fine arts and applied arts, work and products of all human knowledge” (Choay 2008, 11).

Following a period of forgetfulness, several projects aimed at the development and conservation of such plaster collections have been developed by other Professors (Viriato 2005).

In the scope of the PhD research entitled “A Conservação e Restauro de Esculturas em Gesso”, there are various actions taken in its prevention, conservation and restoration as well as in its dissemination.

Documentation and photographic survey

The process of documenting is the first step to take concerning the collections’ preventive conservation (Matos 2014). The sculptural collection that since 1982 has had an inventory of the its sculptures as well as their state of conservation is a good example of the importance of the process of documenting. In 2004 a new inventory was made in which 960 sculptures of different categories have been identified – busts, torsos, sculptural groups, architectural elements, among others.

Currently, there is a deficiency in the inventorying of silicone moulds, some of which have been created under the Centre for Sculpture and Related Technologies from the School of Fine Arts, which aimed at resetting and disseminating the collection. From such projects resulted the catalogues “Machado de Castro – Dos Conventos de Mafra a S. Francisco” and “Tasselos – Passado/Presente”.

The students attending the course on Laboratory on Conservation and Restoration will sporadically, from this year on, work with the inventory records of the moulds that compose the course, continuing the existing numbering.

In the management of the collection documentation the Faculty of Fine Arts, University of Lisbon has acquired the programme INART – Companies of the Future where all faculty collections will be handled together in a single and uniform tool.

In order to complement the constituent information on the inventory sheets, we have taken detailed photographs of the signatures (fig. 2), marks and stamps which on the long term may contribute to develop further knowledge on the origin of such artwork. Since “photography (…) is an integral and specialised part of collection documentation” we have been taking photographs with natural light, low light as well as with ultraviolet light in order to create a more complete and visual archive (Ladkin 2004, 17-32).

Figure 2 - Signature of the former in the area of the junction of the neck, in the sculpture Antínuo de Belvedere

Hygiene, storage and monitoring

The packaging of collection artwork directly depends on the set of conditions and characteristics of the building where they are stored as well as the space and the collection itself which may sometimes condition the type of furniture chosen to install in a given space, for instance. The technical collection of the Faculty of Fine Arts, University of Lisbon is located on the on the lower ground floor instead of on an upper floor where existing risks are less prominent since this building was once the convent of São Francisco da Cidade and also due to the fact that there are mainly classrooms on the first floor.

Sculpture storage, especially on large scale, constitutes several challenges. Sliding shelves are a very practical solution to adopt, however due to the diversity of sculpture size, weight and sometimes fragility, it has been decided to keep the shelves static and open, in order to avoid any abrupt movements (which are characteristic of cabinets or vertical sliding drawers) while also keeping room between them, facilitating the handling of artwork.

In bookcase storing, each artwork contains a label showing its inventory number which can also be found on the shelf with the existing number of copies, facilitating its search. The students have also been mapping the location of each collection’s artwork that is placed in shelves.The sculptures that are not in shelves are placed on a wooden platform with no direct contact with the floor, while the heavier sculptures are placed on a four-wheeled structure (two with a locking system and two without) in order to avoid possible water or capillary infiltrations. In Joana Amaral’s words, “All systems, whether cabinets, shelves or filing cabinets should be raised a few inches from the ground, thus enabling an effective cleaning as well as other maintenance activity” (Amaral 2011, 27).

The material study through methods of examination and analysis in preventive conservation intends to contribute to the study and/ or enrichment of the database through the comparison of changes that the artwork suffers due to the conditions met while in storage. In the specific case of a sculpture from Machado de Castro, the performance of radiography helped us realise that the presence of iron oxides on the plaster’s surface was not due to its internal structure as it was initially believed, but rather to poor packaging while in the collection. This has caused a migration of oxides from the shelves to the plaster’s surface, which made us become aware of the protection that should compose each shelf, in case they are made of iron.

This study also contributes to a closer monitoring of the evolution of the states of conservation. The analysis of conservation status allows the creation of a database of the original material without any addition, which we can use at the end of the intervention so that further additions are distinguishable.

The monitoring of variations in relative humidity and temperature values has also been conducted (fig.3). The last registered values recorded during the admission of the other part of the collection showed 16,5º of temperature and 66% of relative humidity.

Figure 3 - Example of Temperature and Relative Humidity Index Chart, inside the storage, from March 3 to April 7, 2017 (made by Inês Cavaco – student)

However, it is worth mentioning that some authors have been studying this matter and indicated values such as: temperature between 13º to 18ºC and 35% to 45% of relative humidity (Chapman 1997, 2) or temperatures of 21º to 23ºC and 45% to 55% of relative humidity (Bolognese 2008, 207). It is important to note that the “choice of relative humidity must always result from a compromise between all factors determining it” (Casanovas 2008, 96). As Garry Thomson stated in 1978, there cannot be such thing as universal rules that define environmental conditions (Thomson 1978, 88).

Thus, the indicated relative humidity values for plaster artwork should not be taken as universal values. We should take into account that if sculptures are kept in a given place for a long period of time, they will adapt to the temperature and relative humidity values and stabilise.

Public Awareness and Education

Public awareness and education are increasing both in the public sphere but also in the entire academic community and society in general. What we are today, what we know and do, is intrinsically linked to our past and to our heritage. And for that reason, scientific collections should be used as training tools for the dissemination of our cultural heritage.

One of the first measures adopted in the sculptural collection was the controlled and authorized access after a visit request. As referred by Nicola Ladkin, “the controlled access to the collection (…) fulfils the mission of the museum in what concerns education and interpretation, protecting, at the same time, the collection” (Ladkin 2004, 17-32).

Since the creation in 20082009 of the course Technological Studies and Laboratory of Conservation from the Bachelor Degree in Sculpture, the students’ engagement in preventive conservation has become more frequent. This interaction also raised their awareness for the heritage value of the collection and its care. Likewise, they also realise the past to the point where they can use it in the present in order to build their future. During this course, the students interact with the conservator-restorer (fig.4) whose commitment is to conserve heritage at the same time as, in a dual position, they collaborate with the Professor who teaches and helps in the understanding of the valorisation of heritage and patrimony present in this plaster collection. They carry out the inventory process in a plan that helps the localisation of the remaining pieces of work in reserve on shelves or exposed in corridors.

Figure 4 - Students collaborate with the professor in preventive conservation of the plaster cast storage

The society in general has had access to the sculptural collection either through the organisation of Heritage Days or through activities promoted by the Faculty, such as Open Galleries in which the visits to the collection are, for safety reasons and when there are groups composed by a maximum of 8 people, always performed with the presence of a Professor/conservator-restorer. This on-site access to the collection awakens and stimulates interest in Heritage.

Throughout Europe there are several plaster cast collections with replicas of the most emblematic monuments and artworks. In the history of the academies of Fine Arts, the reception of these plaster replicas focused mainly on the pedagogy, and the replicas served as models in the drawing, painting and sculpture classes. The effort made by the technical reserve of sculpture of the Faculty of Fine Arts of the University of Lisbon underlines that these replicas, in addition to their main function, can contribute to other didactic-pedagogical activities.

In 2018 the project “Another way of seeing: Feeling!” took place. Teachers and blind students of the Helen Keller Center were invited to the Faculty of Fine Arts of the University of Lisbon and given a rare chance to touch replicas of sculptures in a museum - in this case a University Museum. This project presented to existing collections of plaster sculptures, a way of solving a common and transversal problem - that the exposed art cannot be touched. This project invited blind students to feel the shapes of the sculptures, to discover outlines, defining lines, the volume and even the emotions in plaster replicas (fig.5).

Figure 5 - The sense of touch - happiness, the exchange of knowledge, the joy of children touching art!

It was proposed, with this project, to deal with another way of approaching art, with a simple solution: the reproduction of plaster works near by the original in marble or bronze, make it possible to achieve a greater sensory interaction with the art and bring more children and educators close to the heritage (Frade 2018, 569-579).


In the follow up of a loan request, an evaluation/analysis of the artwork is made by the conservator-restorer and only after a favourable opinion will it be allowed to be borrowed. In other words, it needs to meet all the necessary conditions for safe handling. This assessment is made in the loan document through a “written and visual description of the artwork’s appearance” (Ladkin 2004, 17-32). A file/document where both the Faculty and the institution requesting a loan agree the loan conditions is opened. The insurance and conditions of transport (explicit in the following section) as well as an indication of existing exhibition rules are, therefore, determined. But not only the loan requests that are independent from the Faculty require a document. The internal requests for artwork to be handled in classrooms have a form in which a diagnosis of its state of conservation is made and that determines whether it has the conditions to leave the collection or not, the inventory number of the requested artwork as well as the amount of time that it will be in classroom context. In case the artwork does not have a copy, a liability form document will also be used. Only then will it be possible to hold control, besides the help provided by other Professors, and to take care of the artwork in the collection.

Requirements for plaster work transportation

In what concerns the transportation of plaster work, it should always be done in boxes (fig.6) lined with plates of expanded polystyrene while the artwork itself must be packed in polyethylene. In case of transporting a sculpture for an exhibition, it must be packed in a way that avoids any damages or possible eventualities caused during driving, such as sudden breaking.

The internal circulation must be executed by using a pallet jack (fig.6) or small cars with small tires. Transport vans must have air suspension, temperature control as well as bollards. Suspension is a matter of concern that dates back from the Napoleonic era and the transportation of sculptures from Rome to Paris. As Brigitte Bourgeois points out, “before the preventive conservation manuals, the commissioners were well aware of the difficulties of having to prevent all changes susceptible of damaging the artwork” (Bourgeois 1999, 156). The French government has nominated two commissioners in charge of sculpture transportation, who received advice from Valadier, Canova or the sculptor Joseph-Charles Marin (Bourgeois 1999, 156), this transportation made use of conservative boxes “in which the organisation of objects inside of it was crucial. Thus, the fixing boards were designed by wooden sculptors and not by carpenters, so that, and as Pâris said, the contours of the statues are precisely followed” (Bourgeois 1999, 156) and accompany the characteristics of the car that will proceed to the transportation. “Regarding land transportation, foreseen for the most delicate and precious artwork, it has been made in ordinary cars or sometimes in cars with specific suspension to cushion collisions and purposely used for such kind of transportation” (Bourgeois 1999, 156).

Figure 6 - On the left: conservative box and on the right: pallet

Temporary Reserve and its Extension into New Spaces

The secondary reserve where part of the sculptural collection corresponding to part of the ornamental sculpture was to be found, did not meet any of the conservation requirements: from water infiltration through the walls to dirt deposition coming through the tiles while registering 13ºC of temperature and 84% of relative humidity.

The suitability of old buildings to Faculties, Museums and/ or Collections implies saving resources (Conçalves 2008, 4). It is a complex requirement to transform a place in order for it to meet all the necessary conditions to receive a collection; it “involves a complex problematic, particularly in what regards the collection’s preventive conservation, which may require the initial investments for the building’s adaptation” (Conçalves 2008, 4).

The enlargement work that directly connects the sculpture technical reserve with new spaces that will receive part of the collection starts with the overthrow of walls and door openings (fig.7) as well as rehabilitation of walls and painting, increasing the number of classrooms assigned to the course of Laboratory of Conservation and Restoration of the Bachelor Degree in Sculpture.After the collection has passed through different places (Matos 2014), this year we managed to gather the entire collection in only one place, keeping the exposed artwork in the corridors, classrooms and offices. In this new space continuous to the existing technical reserve, we extended the safety procedures such as fire detectors and the placement of two extra fire extinguishers.


Transportation has been carried out by an artwork transport company which was always followed up by the conservator-restorer. The transporting vans that have been used fulfilled the requirements already mentioned above, even though, it has not been possible to transport about 500 pieces of artwork in separate conservative boxes. Very strong plastic boxes with polyether-urethane foam and multicellular structure have been used to proceed to artwork transportation, while for artwork of larger dimensions, boxes lined with polystyrene plates were used and straps were placed to secure the artwork. The artwork transportation took a total of 7 days and 15 journeys.

Figure 7 - The enlargement of new spaces


Since it is not possible to have the appropriate furniture, the pre-existing shelves were used, which allow air circulation and are very resistant. Although in the packaging of two-dimensional artwork one refers to drawers, the work transferred from one collection to another were rather humid and therefore not suitable for enclosed spaces. We also took into consideration the type of material that in this particular case is plaster, which is characteristic for its humidity absorption capacity. We also placed a ladder with a landing area and wheels with lock so that the artwork in higher shelves can be safely accessed.

Figure 8 - The new spaces with the pre-existing shelves


In managing the sculptural collection of the Faculty of Fine Arts, University of Lisbon, the process of preventive conservation has been a routine registering constant progress. In the context of our PhD investigation, preventive conservation has become one of the main priorities. We have been further developing work that was initiated by other Professors, students and technicians by adapting methodologies with the help of technology and science. Without the possibility of having the ideal means to store them in the collection, we do not cease to put into practice the necessary measures to minimise all effects of degradation. It is, thus, a work in constant evolution which aims at fulfilling the functions of the collection: to teach and diffuse knowledge on art in a space that gathers memories.

Marta Frade (PT) began her training at the Professional School of Heritage Recovery in Sintra in 1997, where she cultivated her interest in the heritage executed in plaster. This material proved to be of the utmost importance in her academic career. She completed her degree in Conservation and Restoration at the Polytechnic Institute of Tomar in 2005. Since 2011 she teaches as an Invited Assistant Professor of the Faculty of Fine Arts of the University of Lisbon and finished her PhD in Conservation and Restoration of plaster sculpture in 2018.


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  1. This article is an updated version of an article published In Colecções de Arte em Portugal e Brasil nos séculos XIX e XX, As academias de Belas-Artes Rio de Janeiro (2016), ARTIS – Instituto de História da Arte da Faculdade de Letras da Universidade de Lisboa - Programa de Pós-graduação em Artes Visuais da Escola de Belas Artes da Universidade Federal do Rio de Janeiro, Lisboa, Caleidoscópio. [return]