III. Plaster Decoration: The Stucco Makers from Southern Switzerland at Work

Introduction

This article describes the materials and techniques employed by Ticinese stucco masters when they worked in their homeland (Fig. 1).¹ Plaster decoration is an ancient artistic technique, widely used since before classical times, that uses mixtures called stucco mainly based on lime, sand, and marble dust to create architectural decorations and three-dimensional works in imitation of marble.² A stucco decoration is usually made up of a supporting structure using bricks, stones, wood, nails, and metal bars; a first base layer of plaster for defining volumes, which was composed of lime and sand (sometimes with gypsum as an additive); and a finishing layer, of lime and marble powder, which may have received a surface polish or a whitening layer (Fig. 2). This “recipe,” behind its apparent simplicity, hides a large number of variations and tricks. A great deal of experience, an established ability to handle a material that was not easy to mould, and a keen artistic sense were fundamental skills required to create works of art. In fact, not all plasterers succeeded in becoming masters in their field; some of them stopped at intermediate roles such as “carver” or remained simple “squarers” in charge of executing the frames and serial elements.³

Between the sixteenth and seventeenth centuries, the stuccatori from Italian Switzerland took part in the decoration of the main building projects in all of Europe.⁴ Their methods of organizing their work, their ability to collaborate with other artists and tradesmen, their attention to updating formal requirements, and their strong ties to their native region—all of which maintained a continuous renewal of ideas and workforce—represented their strengths. These qualities probably would have been insufficient if they were not also accompanied by a particular ability to master the challenging aspects of making art from stucco*.* Despite previous research and numerous publications that have explored the works of the stuccatori and their cultural context, there has yet to be an examination of the art and industry of these artists, specifically of how their practical and technical “know-how” contributed to the great professional and artistic success that they enjoyed.⁵ Our main aim was to investigate the techniques that some of the most important stucco artists, such the Silvas of Morbio Inferiore, the Casellas of Carona, and the Colombas of Arogno, used to create significant works in their places of origin and to identify whether they worked according to a modus operandi common to Ticinese artists or whether each artist, “family,” or workshop had its own individual working techniques.⁶

In order to facilitate comparisons between works and masters and make it possible to point out the variations and continuities in their working methods, the analysis was limited to works located within a precise geographical context, mainly between Lugano and Mendrisio in southern Switzerland, and timespan, a little more than a century, between the late sixteenth and the early eighteenth century, in the period when the art of stucco was at its height. We can therefore imagine that the materials available were the same and that similar formal references and conditions may have influenced the organisation of workshops.

The research was developed by bringing together historical sources on the commissions of stucco decoration, art technology, archaeometry, and materials science, to put in perspective information gathered from a variety of sources. Written documents pertaining to the materials and the techniques used, preserved mainly in parish archives (including building books, contracts, bills, invoices, and receipts), and until now little explored, were a rich source of information about the history of the design and making of stucco.⁷ Visual analysis of the works of art and of their technical and executive features allowed for a better understanding of the fabric. Material analyses (chemical and petrographic) of the stucco decorations were crucial to understanding the characteristics and properties of the materials used,⁸ and to compare, with an archaeological and interdisciplinary approach, the analytical data with the historical and materials information. Experimental archaeology reproducing replicas of the stucco decorations was fundamental to establish a stronger understanding of the connection between material mixes, their use, and their final appearance.

Studying the technical aspects tied to the artistic production processes required that the researchers be able to tackle empirical and technical knowledge based on expertise that was not codified or rigidly defined. Such expertise was handed down in the workshop from father to son (or from master to apprentice), according to models and recipes that are now unknown and can only be reconstructed through an analysis that involves the intersection of direct and indirect sources.

The develoment of a working method

During the research on the art and industry of stucco decoration in present-day Canton Ticino, we were able to develop a systematic and methodological approach for the study of the technology of stucco making.

For the early modern period, the manuals and printed treatises that describe the technique used in the creation of stucco were collected by Carla Arcolao, and discussed in different contributions in the meeting of Bressanone in 2001,⁹ while numerous references to the European artistic literature (including the art of stucco creation) were included in Christoph Zindel’s 2010 text.¹⁰ Although these descriptions have enabled a better comprehension of the original works of art, the manuals and treatises, by their nature, retain a general and widespread knowledge far from the complex reality of single objects that are precisely described exclusively in the documents from worksites. Only through reading the archival sources was it possible to find the information required for this study. In certain cases, the documents even describe basic details about those who performed minor tasks, such as the payment of a manual laborer for the “l’innaffiatura degli intonaci anche nei giorni di festa” (watering the plaster on celebration days), an apparently insignificant detail, but one essential to show the care with which even great artists such as Pietro da Cortona monitored the curing of their works.¹¹ These fragments of information are precious, but unfortunately also rare and hard to find.

The empirical knowledge of the workmen is difficult to reconstruct, as this was mostly transmitted orally, but sometimes the documents, especially in the case of disputes, report the complexity of the reasoning at the root of the choices that were made. These documents are particularly valuable and often are the only ones to preserve the full cultural importance of the actions taken. Other important documents for an understanding of how contemporaries appreciated these decorations are reports to certify the quality of the work after completion. These assessments, done by other stucco makers or other experts, sometimes point out technical or visual defects of the works or, on the contrary, even suggest awarding an extra bonus to the plasterer who created a work of exceptional value.¹² The archival research often provides information not only relating to the quantity and provenance of the materials used, but also about the workmen and their way of operating, or about the events connected with the commission and the progress of the work.¹³

The main source of written information was found in parish archives, which have yet to be fully explored. Thus far, they have been used by art historians mainly to research names and attributions (Figs. 3a,b).¹⁴ Many parish and diocesan archives contain a significant number of building documents that are fundamental for studying the dynamics of worksites, in order to comprehend the production mechanisms and social organization of the work. Wherever possible, all the parish archives related to the stucco works studied and the patriciate archive of Castel San Pietro were analysed.¹⁵ They revealed extraordinary documents such as contracts, lists of materials, and payment notes. For instance, the Domaso parish archive preserves all the documentation about the execution of the decorations of the Chapel of Saints Francis and Anthony in the Church of San Bartolomeo, from the initial agreements between the clients and Agostino Silva to the completion of the project. The documents provide a daily account of what occurred on the site, describing the arrival of the materials and the people working there.¹⁶ Other archives particularly rich in documents were those of Valenza, Careno, and Morbio Superiore. Finally, it was essential to consult the archive of the Office of the Cultural Heritage (UBC – Ufficio dei Beni Culturali) in Bellinzona to retrace the conservation history of the stucco decorations, which were often modified and widely altered during past restorations.

Understanding these complex aspects of the art of stucco also required familiarity with the technical terms of the documents to gain a full understanding of the words used in the ancient written sources. Sometimes the words have changed, they are written using vernacular terms, or they refer to objects that are no longer used or available.¹⁷

The choice of the sites to be closely examined took into consideration various criteria: the richness of the documentary sources, allowing for comparison between written documents and the work realized; and the accessibility of the upper part of decorations and the rear of statues to gain a complete view of all the technical details normally hidden when viewed from below. It was also crucial to observe stucco decoration in a poor state of repair, which revealed all the constructed internal layers including the masonry support structures, the metal anchorages (sometimes protected by thin cords or cloth), the thick coarse layers, and finally the white finish of lime and marble dust (Fig. 4).¹⁸

It was difficult to find works that met all these criteria. Some decorations that are highly interesting in technical-artistic terms were not accompanied by documents that retraced the phases of their execution, as many documents or books have been destroyed or dispersed over the centuries. Other decorations, perhaps well documented, no longer exist, have been greatly altered, or cannot be observed closely. Therefore, we had to cross-check the data collected to compare it with written sources and accessible sites. Some places could be investigated in greater depth, such as the Oratorio Imbonati at Cavallasca in Italy, the Chapel of the Madonna in the Collegiate Church of Balerna, the main altar and the altar of San Carlo in the Church of Sant’Antonino at Obino, the Shrine of the Madonna d’Ongero at Carona, the Church of Sant’Eusebio at Castel San Pietro, and the Oratory of Sant’Anna at Morbio Superiore in Switzerland. In other churches it was possible to conduct only partial research.

To clarify the activities of the Silva family and of Alessandro Casella, our field trips to the Italian provinces of Como or in Valtellina proved useful, enabling us to collect documentary material and observe works where their activity was certain and well documented. The Oratorio Imbonati at Cavallasca and the Church of the Transfiguration (or Sant’Ambrogio) in Cantù made it possible, due to their poor state of preservation, to observe technical aspects in great detail, including the presence, form, and construction of the supporting armature, the layers of mortar, and the finishes (Fig. 5). Whenever possible, we also consulted documents already quoted by other researchers, Luigi Brentani in particular.¹⁹ Although not directly related to our case studies, these documents belonged to the same geographical area and historical period, and so provided useful comparisons. Hence, despite the difficulties surrounding the start of our work, the data collected enabled us to reconstruct a fairly complete framework of knowledge.

With the selected works, visual observations were made to check and extend the information gained from indirect sources. The technical execution was documented and described in detail. The elements were subdivided according to three main types: architectural decorations (plain or moulded cornices), bas-reliefs (festoons and garlands, figures not completely projecting), and figures in the round.

The close-up examination of a work allowed for the identification of many details related to how it was created. As stucco is a plastic and malleable material, while it is fresh the surface is easily marked, so the smallest signs of the tools used are permanently preserved in the surface once it is dry. These signs can sometimes be almost invisible, readable only in certain light conditions, such as raking light. In other cases, they appear only with special instruments, such as a UV light or a portable microscope. With careful observation of the work, it is possible to identify how many layers it is made from, the tool used to shape the decoration (in wood or in metal, for example), and the presence of stamps or moulds.

On the basis of these observations, specific areas were selected based on their potential value for further scientific analyses. Technological analyses of the stucco were conducted with a particular focus on understanding the composition of the mortars, detecting the amounts of the different constituent ingredients (the relative amounts of binder and aggregate, the amount of gypsum, the nature of the lime), and identifying their structure and stratigraphic sequence to compare the analytical data with historical and material data. In the case of substantial purchases of gypsum at the building site, for example, it was important to understand whether and how the gypsum had been used, or, in the case of a particular material aspect, to understand whether the mortar had a different composition than that of neighboring areas.

The analytical research was carried out using methodologies widely recognized in this specific field and according to the same analytical protocol, which allowed for homogeneous and comparable results. The scientific analyses were conducted on approximately 250 samples, a significantly higher number of samples than those examined in other studies.²⁰ Approximately ten samples were taken for each case study. Despite their large number, this is still less than one would have wished, considering that stucco is a highly heterogeneous material and that variations in composition within the same decorative element, especially in a statue of complex form, are frequent.

Considering the characteristics of the work and its state of preservation, a specific sampling strategy had to be developed. As far as possible, we always tried to take an internal sample from the coarse layer that was as close as possible to the reinforcement bars and the associated finishing layer and, within the same case study, to take samples from works attributed or attributable to different hands, aware of the fact that it is not possible to establish a simple analogy between a material and an artist. Our investigations almost exclusively concerned the mortars and internal structures, as the polychromes, gilding, and surface treatments were often profoundly modified over time.

After a preliminary examination both with the naked eye and a binocular microscope with micro-photographic documentation at different scales, the analysis of the components (binder and aggregates) in their stratigraphic sequence was carried out using a polarizing microscope both in incident (visible and UV light) and transmitted light (PLM) (Fig. 6).²¹ Microscopy in incident light allows for the identification of the stratigraphic sequence of the sample including the number of layers, color, composition (where applicable), thickness, and adhesion. Microscopic analysis in transmitted light allowed the examination of the mineral phases (binder and aggregates) and the assessment of the proportion of the ingredients. A Scanning Electron Microscope (SEM) was used to investigate the elemental composition of the individual layers and to study the morphology and texture of the mortar binder.²²

It was more difficult to characterize the organic component within the mixtures, which is essential to improve the plasticity of the mortars and their workability.²³ The presence of these additives was suggested during visual observations. They seem to be present, for example, in the festoons of the ribs of the nave in the Church of the Sacro Monte of Ossuccio, in the presbytery of Santa Maria d’Ongero in Carona, and in the thin leaves of the vault of the Chapel of San Giovanni Battista in Morcote. Their properties have been verified by making replicas. However, organic additives are not always scientifically determinable due to the low percentage present in the mixture and the degradation they undergo over time.²⁴

The archival documents contain little information about the use of organic additives. The purchase of eggs or soap to be used for painting and polishing faux marble columns is sometimes recorded,²⁵ but we cannot exclude the possibility that milk or casein was added without being mentioned in the accounts. Less plausible, however, is the “silent” addition of more expensive oils, probably from linseeds or olives.²⁶ The search for organic material in the plasters was conducted using two different techniques: FT-IR FPA spectroscopy and the DOT-Elisa solid-state immunological technique capable of identifying different types of proteins such as albumen, milk, and glue.²⁷ FT-IR FPA investigations on several samples revealed the presence of a lipid component, while the protein component was only identified in traces. Interestingly, with the DOT-Elisa technique, the results were mostly negative. Based on these findings, it can be assumed that the material sought was indeed absent, or that it was below the detection threshold of the analytical technique. In some samples where the presence of organic material was not directly detected, calcium oxalates were identified that could be associated with an original presence of degraded organic matter. During our research, we could not investigate the role and presence of organic additives as it would have required a more in-depth and comprehensive study, which was not possible to include in this part of the work. The ability of these stucco masters to change the working and setting properties of their plasters using different organic and inorganic additives is a fascinating field of inquiry.

The X-ray analyses to detect internal iron bars were conducted on the Oratorio Imbonati of Cavallasca and on some decorative elements in the churches of Castel San Pietro, Arogno, and Santa Maria d’Ongero.²⁸ The X-rays allowed us to observe the internal reinforcements, the different materials from which they were made (iron bars, iron wires, nails of different shape and size), and how they were made. Some of these reinforcements were constructed by the artist with great care in the choice of materials and their connections, while others show that the internal bars were inserted into the mortar in a hasty manner as the work progressed (Figs. 7a,b).

To clarify and better understand certain aspects connected to the use of materials, the creation of replicas was extremely important (Fig. 8).²⁹ These practical experiments had different functions, including verification of the working properties of a recipe or a particular material. For example, the use of different percentages of gypsum empirically evaluates when the plasticity of the mixture changes, or how long it remains plastic or tends to dry more quickly, making possible a better understanding of what is described in the sources. This part of the research was developed with the understanding that the materials used were not always the same, that in the sources some information could be taken for granted and thus not described, and that there is always a certain margin of error in the creation of a replica. Despite these limits, this process of “experimental archaeology” allows the acquisition of information that is not possible to acquire in any other way.

The materials and techniques

A first topic of great interest was connected to the understanding of the materials that were used, their provenance (whether they were local or imported), the processes to which the raw materials were subjected, and which workers prepared or used them.³⁰ The choice of a specific material was never unintentional: it could be based on cost or availability, or it could be connected to the special qualities that the artist expected through its use. The area around Lake Lugano is rich in clay, stone, and gypsum quarries. All the materials needed to create plaster decorations were readily available nearby.

The construction sites of Basso Ceresio alternated purchasing marble and gypsum,³¹ or gold or precious pigments, between the Como building market and Riva San Vitale, an important centre for the production and sale of bricks and lime.³² The kilns used for the flourishing activity of brickmaking were in fact also used for making lime, employing the dolomitic limestone available in the area.³³ Sometimes gypsum and marble were bought directly from the nearby quarries of Nobiallo and Musso, respectively.

The bricks, called quadrelli or pianelle depending on their size, were used to build the altar wall supports, the pilasters, and the entablature, and to provide a solid structure for all the projecting elements, both architecture and the decorative apparatus.³⁴ The pianelle, in particular, were small, thin paving slabs well suited for execution of the different profiles of the decorations (Fig. 9). The more closely that the outline of the supports matched the final one, the easier and faster was the work of the stuccatore. To facilitate the application of the final layer of stucco, bricks with rounded shapes or with a torus mould were used. These particular bricks are also mentioned in the Valenza archive³⁵ and in the architectural treatise of Alessandro Capra (Figs. 10, 11).³⁶

A coarse mortar (composed of lime, sand, and sometimes gypsum) was laid on the supporting structure, followed by finishing mortar (composed of lime and marble dust). To support the decorations projecting from the wall, nails were used, often with large heads, while the large three-dimensional statues had a metal or (more rarely) wooden framework.

Iron was an indispensable component of a stucco work, used both to give shape and support to projecting parts and to keep them anchored to the wall behind and prevent them from falling (Fig. 12). Sometimes the iron was referred to as a single undifferentiated supply for use by the stuccatore.³⁷ Other times it was described precisely using terms such as vergella or quadretto, thin and thick iron or copper wire, or nails of different sizes and length.³⁸ In the overall cost of a stucco decoration, payments for ironwork had a significant impact. To shape the large wings of the angels and other projecting three-dimensional elements, a special metal bar called a vergella was used (Fig. 13). Writing in the mid-1800s, Francesco Cherubini describes this as “a kind of iron band or strapping struck in the plane in such a way that it takes the form of a wavy or scalloped ribbon.”³⁹ The English term for the modern product with similar characteristics is “wire rod.” In the historic production, a rod of square cross-section, measuring about a half centimeter per side, was beaten and twisted in such a way that it could easily be bent and adapted even as the individual stucco works were in progress. The irregular surface, in some ways similar to that of modern improved-adherence reinforcement, also favored good adhesion of the preparatory mortar layers. Vergella was mentioned in almost all construction documents, testifying to its widespread use.⁴⁰ Wooden elements were used only rarely as internal reinforcements or anchorage: it was clearly a less expensive option but lacked the flexibility to follow the complex shapes of the figures.

The documents consulted did not suggest any particular attention to the selection of types or qualities of lime in order to prepare the stucco (mortar mix). Analyses of mortar samples showed that in most cases a magnesian lime was used, produced by firing local white dolomites.⁴¹

In Domaso, lime is bought in early October, slaked immediately, and then used in May after about eight months of seasoning. Treatises confirm this timeframe as part of best practices, although for finer finishes the authors suggest the use of lime seasoned for as long as several years.⁴² According to these sources, the older the lime, the easier it is to work, and the more durable it makes the stucco.⁴³

In archival documents, sand is usually referred to by the generic term sabbione, described by Cherubini as a coarse-grained sand.⁴⁴ In several works examined, the grain size of the sand used for the internal layers was indeed coarse, mixed, and unselected (Fig. 14). More details on the quality and origin of the sand are found only in documents concerning the Castel San Pietro worksite: the nearby “valley of Coldrè” was the source for four wagons of sabbiono sottile (fine sand) and four wagons of sabbione.⁴⁵ A sole mention of the use of multiple types of sand was found in the documents for the execution of stuccos of the Altar of the Immacolata in the Duomo of Valenza. For this work, by Antonio Colomba, there is mention of three different types: six barcielate (barrows) of ordinary sand, four barcielate of red sand, and one barcielata of granite sand, possibly a coarse-grained material.⁴⁶

Another key ingredient in making stucco decoration was gypsum. In worksites subject to sampling and analysis of the constituent materials, gypsum was used mainly in the internal layers and very rarely in the finishing layers.⁴⁷ The presence of gypsum in the coarse mortars assures the stuccatore a firmer and more controllable material, because the mortar does not distort during the setting process. The addition of a small percentage of gypsum (3–5%) sped up setting time and prevented excessive shrinkage, averting the formation of shrinkage fractures that would ruin the final effect of the work. Its presence in the finishing layers, on the other hand, was very rare because it shortened the drying time of the thin white finishing coat and made the material more difficult to work with.

Differences have been observed between the execution of architectural decorations, often made without gypsum, and more complex sculptures or three-dimensional works in which gypsum played a decisive role in the creation of the modelling. The amount of gypsum added into the mix was usually variable among the different plasterers and from area to area within the same work.

Variations in the use and composition of the coarse layer were also observed. Sometimes the differences in mortars were macroscopic and recognisable to the naked eye, as in the example of a stucco from the Sanctuary of the Madonna d’Ongero in Carona, which is characterised by a mix rich of clay aggregate (Fig. 15), or the detail of the putto’s leg from the chimney piece in the Carlone house, which has mortar with a high percentage of gypsum in the inner core (Fig. 16).

The use of fibres and ropes was also widespread (see, for example, the hemp found behind the arm of Saint Gregorio in the Sanctuary of the Madonna d’Ongero or the wings of the angels of Sant’Anna in Morbio Superiore), often for the construction of protruding parts that had to be light and flexible (Fig. 17).⁴⁸ Bits of cord, fabric, and other fibres were also used to aid the adhesion of mortar, to increase the volume of reinforcement, and to connect metal elements. Purchases of these materials were completely regular; their use was described in Francesco Carradori’s treatise on sculpture and can be observed in the Imbonati Oratory in Cavallasca.

The white colour of the stucco decorations, which made them resemble marble, was achieved by the mixture used for the thin finishing layer, which varied from one or two millimetres to half a centimetre, and was composed of lime and marble dust in a ratio varying from 2:1 to 1:1.⁴⁹

On worksites in Basso Ceresio, the marble used was mainly from Musso, the only suitable source in the area. A note at Domaso explicitly stated that the marble came from Musso, was reduced to powder by the labourer, and then sieved.⁵⁰

To give greater realism to the robes or attributes of the statues, “real materials” were also used, as can be seen, for example, in the habit of St. Peter of Alcantara in Santa Maria dei Miracoli in Morbio Inferiore, closed by a real cord, or in the crosses carried by the saints, often made of white-painted wood (Fig. 18).

To speed up the decoration of cornices, wooden moulds were used. They were pressed on the fresh stucco to imprint the surface that was then finished by hand (Figs. 19a–g). In contrast, the use of moulds for shaping statues or faces or the use of casted elements was very rare; almost all these decorations were done freehand directly on site.

In the area and in the time frame examined in our research, the stuccos were usually white, sometimes finished with a layer of lime to make the surface smoother. The gilding was rare as it was very expensive and frequently done at a later time, when the community or the patrons could gather the necessary sum of money to purchase the precious gold. This particular work was always assigned to specialized professionals.⁵¹ Sometimes it can be seen that the parts of the decorations intended for gilding were prepared with a simple layer of yellow ochre, for definition of the extent and final effect of the work.

Conclusion

The study of the techniques with which some important stucco decoration was created supports the consideration of the role of materials and techniques in the interpretation of stucco works, going beyond a purely formal reading of the decorative schemes, thus placing this art in a wider cultural framework and providing important information to guide future conservation actions. The new data has also expanded with the knowledge of art historians, verifying the existence of “schools” and working groups, contributing to the clarification of attribution and dating and to the comparison of the decorations created by these artists outside their homeland and in this way to the evaluation of the role of the technique (in its variations and endurances) in the realization of their works of art.

During our research, we were able to observe not only the variety in the composition of the mortars but also great technical diversity among the plasterers, highlighting similarities and differences within the same geographical and temporal context. There was no standard recipe for either base or finishing mortars; instead, the masters prepared different mixes of sand and lime on a case-by-case basis, in view of the materials at hand, their observations of needs and conditions, and their accumulated expertise. The case of the Silva family is exemplary, in which the three generations of artists used a very similar basic mortar, which was worked in completely different ways. Some plasterers, Agostino Silva and Alessandro Casella in particular, worked in spurts, quickly superimposing layers of fresh mortar; others, such as Francesco Silva, worked more slowly, arriving at the desired result with a stucco that was rendered almost like clay. In Francesco Silva one can see the the executive precision and polished surfaces, in his son Agostino the ability to improvise and work quickly, in Casella’s decorations the many expert hands working at his side, all equally skillful and in perfect harmony, and in Colomba, finally, a “textbook” technique.⁵²

The collaboration among professionals with interdisciplinary expertise was fundamental to complete this research. Art historians, conservator-restorers, and scientific experts were able to exchange their knowledge and discuss open questions with colleagues from other disciplines. It is essential that the historical data from archival research be combined with direct observation of the works, conducted by expert restorers capable of interpreting the material and by a skilled plasterer who knows the difficulties of shaping such ductile mixtures. Finally, a scientific expert must be able to analyse the materials used, to confirm those hypotheses on the composition of the mortar that can be made by observing the works and reading the supply notes of the building site. For a deeper understanding of stucco making, it is crucial not only to identify the constituent materials of the mortars, but also the percentages, the manner of their mixing, the potential use of additives, and, once the mortars were prepared, the time and manner of their use, and any further additions or modifications. All of these factors were under the control of the master stuccatori, allowing them to adapt to their needs a material that by its very nature is difficult to work. Each stuccatore learned to modify the characteristics of the mixes—according to the peculiarities of individual sites, their own personal character and expressive needs, the time available, and the climatic conditions. These adjustments could be done in at least two ways: adding additives to the mixtures (such as oil or casein), or by developing particular treatments of the mortar (repeated mixing, addition of water during the setting phase, etc.). This processing technique was never described in the literature, and it can only be reconstructed by systematically working with replicas.

The project may establish a research method with a strong interdisciplinary focus, crucial for gaining a better understanding of the processing skills needed to realize a stucco decoration. This methodology, shared with other scholars and partners, can now serve as the foundation for developing further projects.⁵³

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Jean, Giacinta, Alberto Felici, Giovanni Nicoli, Marta Caroselli, and Stefania Luppichini. “Art and Techniques of the Stuccatori: Understanding Through Replication.” In Reflecting on Reconstructions: The Role of Sources and Performative Methods in Art Technological Studies. Proceedings of the ICOM-CC Working Group on Art Technological Source Research, Cologne Institute of Conservation Sciences, University of Applied Sciences, September 26–27, 2019. https://www.icom-cc-publications-online.org/4612/Art-and-techniques-of-the-stuccatori--understanding-through-replication-

———, ———, Marta Caroselli, and Giovanni Nicoli. “Le decorazioni a stucco nella Regione dei laghi: un progetto per lo studio delle tecniche artistiche.” In Stucchi e stuccatori ticinesi tra XVI e XVIII secolo: studi e ricerche per la conservazione, edited by Alberto Felici and Giacinta Jean, 11–28. Florence: Nardini, 2020.

———, and ———. “Material and Construction: Stuccatori at Work in Basso Ceresio; Archival Sources and Material Evidence.” In The Art and Industry of Stucco Decoration in Europe from the Late 15th to the Middle of 18th century, edited by Giacinta Jean, and Alberto Felici, Rome: Officina Libraria, 2025, 209-38.

Lavizzari, Luigi. Escursioni nel Canton. Ticino Lugano: Tipografia Veladini, 1859–63; repr., Locarno: Armando Dadò, 1988.

Martinola, Giuseppe, Lettere dai paesi transalpini degli artisti di Meride e dei villaggi vicini (XVII–XIX). Bellinzona: Edizioni dello Stato, 1963.

Monti, Pietro. Vocabolario dei dialetti della città e diocesi di Como. 1845; repr., Bologna: Forni, 1984.

Palmieri, M., M. Vagnini, L. Pitzurra, et al. “Development of an Analytical Protocol for a Fast, Sensitive and Specific Protein Recognition in Paintings by Enzyme-linked Immunosorbent Assay (ELISA).” Analytical and Bioanalytical Chemistry 399 (2011): 3011–23. http://doi.10.1007/s00216-010-4308-1.

Pecchioni, Elena, Fabio Fratini, and Emma Cantisani. Le malte antiche e moderne tra tradizione e innovazione. Bologna: Patron, 2008.

Quagliaroli, Serena, and Giulia Spoltore, eds. “‘Quegli ornamenti più ricchi e più begli che si potesse fare nella difficultà di quell’arte’: la decorazione a stucco a Roma tra Cinquecento e Seicento; modelli, influenze, fortuna. Horti Hesperidum 1 (2019).

Romeri, Massimo. Il percorso di Alessandro Casella dalla Valtellina al Valentino. Turin: Fondazione 1563 per l’Arte e la Cultura della Compagnia di San Paolo, 2022.

Torraca, Giorgio. “Tecnologia delle malte per intonaci e della conservazione degli intonaci antichi.” In Diagnosi e progetto per la conservazione dei materiali dell’architettura, edited by the Istituto centrale per il restauro, 203–21. Rome: De Luca, 1998.

Vasari, Giorgio. Le vite de’ più eccellenti architetti, pittori, et scultori italiani, da Cimabue, insino a’ tempi nostri. Edited by Luciano Bellosi and Aldo Rossi. Turin: Einaudi, 1991.

Vecchiattini, Rita. La civiltà della calce: storia, scienza e restauro. Genova: De Ferrari, 2009.

Vocabolario dei dialetti della Svizzera italiana. Bellinzona: Centro di dialettologia e di etnografia, 1952.

Zindel, Christoph. Güldene Kunst-Pforte: Quellen zur Kunsttechnologie; eine chronologische Übersicht gebundener Quellenschriften zu Baukunst, Bildnerei (Skulptur und Plastik), Malerei, Graphik, Kunstgewerbe, Kunsttheorie und Restaurierung von der späten Antike bis 1900 mit bibliographischen Daten, Kurzkommentar und Registern. Bern: HKB, 2010.

Zumbühl, Stefan, Nadim Scherrer, and Urs Eggenberger. “Derivatization Technique to Increase the Spectral Selectivity of Two-Dimensional (2D) Fourier Transform Infrared Focal Plane Array (FT-IR FPA) Imaging: Analysis of Binder Composition in Aged Oil and Tempera Paint.” Applied Spectroscopy 68 (2014): http://doi.10.1366/13-07280

Notes

1. This article was based on the research financed by the Swiss National Research Fund “The Art and Industry of Ticinese Stuccatori from the 16th to the 17th century.” See https://data.snf.ch/grants/grant/160092. Some of the topics of this article have been further explored in Giacinta Jean et al., “Le decorazioni a stucco nella Regione dei laghi: un progetto per lo studio delle tecniche artistiche,” in Stucchi e stuccatori ticinesi tra XVI e XVIII secolo: studi e ricerche per la conservazione, ed. Alberto Felici and Giacinta Jean (Florence: Nardini, 2020), 11–28; and Giacinta Jean and Alberto Felici, “Material and Construction: Stuccatori at Work in Basso Ceresio; Archival Sources and Material Evidence,” in The Art and Industry of Stucco Decoration in Europe from the Late 15th to the Middle of 18th Century, ed. Giacinta Jean and Alberto Felici (Rome: Officina Libraria, 2025), 209-38. The project was coordinated by Giacinta Jean and Alberto Felici and carried out with the collaboration of Lucia Aliverti (historical and archival research), Giovanni Nicoli (technical analyses), Stefania Luppichini (data management), and Marta Caroselli and Giovanni Cavallo (scientific analyses). ↩︎

2. Claire Gapper, “What Is ‘Stucco’? English Interpretations of an Italian Term,” Architectural History 42 (1999): 333–43. ↩︎

3. Giuseppe Martinola, Lettere dai paesi transalpini degli artisti di Meride e dei villaggi vicini (XVII–XIX) (Bellinzona: Edizioni dello Stato, 1963) 15:24–25, 38, 92. ↩︎

4. Christine Casey, Making Magnificence: Architects, Stuccatori and the Eighteenth-Century Interior (New Haven: Yale University Press, 2017). ↩︎

5. See the recent excellent publications that are sparking renewed interest in stucco decoration, such as: Serena Quagliaroli and Giulia Spoltore, eds., “‘Quegli ornamenti più ricchi e più begli che si potesse fare nella difficultà di quell’arte’: la decorazione a stucco a Roma tra Cinquecento e Seicento; modelli, influenze, fortuna,” Horti Hesperidum 1 (2019); Massimo Romeri, Il percorso di Alessandro Casella dalla Valtellina al Valentino (Turin: Fondazione 1563 per l’Arte e la Cultura della Compagnia di San Paolo, 2022); Alessandra Giannotti et al., eds., “Lo stucco nell’età della Maniera: cantieri, maestranze, modelli” special issue, Bollettino d’Arte (Rome), 2022. ↩︎

6. Information on these artists can be found at https://restadistucco.ch/en/artists. ↩︎

7. The archival sources consulted were: Arogno, Chiesa di S. Stefano, Archivio Parrocchiale, cart. “Documenti antichi da riordinare”; Bissone, Chiesa di San Carpoforo, Archivio Diocesano di Lugano, Conti della chiesa, 1653–1727; Careno, Chiesa di Santa Maria, Archivio Parrocchiale di Pognana, uncatalogued file containing documents on the parish church of Careno, “Libro dei conti, 1668–1699 (Careno)”; Castel San Pietro, Chiesa di Sant’Eusebio, Archivio Patriziale, cart. “Contratti e conti saldati – Inventari Beni Chiesa Parr. 1500/600,” “Libro dove si notta le spesse dil Comune di Castello – Libro dove si notano le spese o ricavate delli Cons.i della Comunità di Castelo S. Pietro incominciando dall’anno 1663”; Chiuro, Chiesa dei SS. Giacomo e Andrea, Archivio Parrocchiale, Ro67I5: “Libro della Scola SS.mo Rosario a Chiuro”; Civo, Chiesa di S. Andrea, Archivio Parrocchiale, libro dei conti: “In questo libro sono descritti i Conti della Chiesa Parrocchiale di Sant’Andrea di Civo”; Como, Duomo, Archivio Storico della Diocesi di Como – Fondo Fabbrica del Duomo, “Libri contabili, 1666–1670,” “19.1–Libri di casa 15”, “Libro Mastro della Vener. Fabrica MDCXXVII,” “Cassa della Veneranda Fabbrica dall’anno 1671 al 1675,” “Fabbrica e Riparazioni”, titolo XVI, fasc. 1 and 5, cart. miscellanea, titolo XXXIX, fasc. 9; Archivio Storico della Diocesi di Como, Eredità, cart. 27, “Stima fatta da Maestro Francesco Bracheto del Palazzo del Balbiano”; Domaso, Chiesa di San Bartolomeo, Archivio Parrocchiale, cart. “Documenti antichissimi,” ex-Matrimonialia n. 4, cart. ex-Matrimonialia: “Scrittura d’obbligo del S.re Agostino Silva per stuccare l’altare di S. Ant.o”; “Notta della spesa, che si va facendo dal s Can.co Manrico et dal can.co Passalaqua per il stucco della capella de SS. Fran.co et Antonio nella chiesa di S. Bart.meo di Domaso…”; Morbio Inferiore, Santuario della Madonna dei Miracoli, Archivio Parrocchiale, libro B: “Libro nel quale si notta entrata et spesa che si fa nella Chiesa della B. V. Maria delle Grazie di Morbio di sotto, 1665–1726,” cart. 11: V. Chiese e Oratori–A5: “Cappella dei SS. Pietro e Paolo (1656)” and “Altari pitture (1671),” “VIII Sostanza Ecclesiale – 2 Cappellania di Paolo Silva”; Morbio Superiore, Chiesa di S. Giovanni Evangelista, Archivio Parrocchiale, Un. 7.2/doc. 1, Registro 4.1: “Libro della Ven. Confraternita della SS. Cintura nella V. Paro.le di Morbio Sup. 1700, Confraternita della B.V. della Cintura”; Ossuccio, Cappelle Sacro Monte e Santuario della Beata Vergine del Soccorso, Archivio del Santuario, “Registro dei conti dal 1699 al 1735”; Valenza, Chiesa di S. Maria Maggiore, Archivio Gasparolo, Scatola 12, Compagnia del SS. Sacramento, fasc. 2, Amministrazione, “Spese fatte dalla compagnia dal 1622 al 1634”; Torricella, Chiesa dei SS. Biagio e Maurizio, Archivio Parrocchiale, “1720/1670 al 1730 / B”: “Libro dove si descrive l’entrata et uscita d’ogni anno dalli priori della Compag.a del Carmine di Torricella”; Vercana, Chiesa di S. Salvatore, Archivio Parrocchiale, Registro senza indicazioni in copertina (from 1611), “Libro de conti della fabrica di s. Salvatore del cne di Vercana Lago e Dioc di Como, et Capella esistenti nella Chiesa parochiale di S.to Salvatore sud.o cominciando dal Anno 1639 avanti”; Villa Coldrerio, Oratorio della Madonna del Carmelo, Archivio dell’Oratorio, libro “Conti della ven. Confraternita della B.V. del Carmelo – dal 1615 al 1661.” ↩︎

8. On the instruments used, see notes 21–22, 28. ↩︎

9. See Lo stucco: cultura, tecnologia, conoscenza, eds. Guido Biscontin and Guido Driussi (Venice: Arcadia Ricerche, 2001). ↩︎

10. Carla Arcolao, Le ricette del restauro: malte, intonaci, stucchi dal XV al XIX secolo (Venice: Marsilio, 1998); Francesca Albani, “‘L’arte di fare’ lo stucco in area lombarda tra XVI e XIX sec.,” in Biscontin and Driussi, Lo stucco, 365-372; Christoph Zindel, Güldene Kunst-Pforte: Quellen zur Kunsttechnologie; eine chronologische Übersicht gebundener Quellenschriften zu Baukunst, Bildnerei (Skulptur und Plastik), Malerei, Graphik, Kunstgewerbe, Kunsttheorie und Restaurierung von der späten Antike bis 1900 mit bibliographischen Daten, Kurzkommentar und Registern (Bern: HKB, 2010). ↩︎

11. Pietro Malcom Campbell, Pietro da Cortona at the Pitti Palace: A Study of the Planetary Rooms and Related Projects (Princeton: Princeton University Press, 1977), 233. ↩︎

12. See Lucia Aliverti, Alberto Felici, and Giacinta Jean, “L’impresa dei Silva di Morbio,” in Pratiche architettoniche a confronto nei cantieri italiani della seconda metà del Cinquecento, eds. Maria Felicia Nicoletti and Paola Verde (Roma: Officina Libraria, 2019), 112–13. ↩︎

13. Aliverti, Felici, and Jean, 95–118. ↩︎

14. See the excellent series of books on Artisti dei laghi published with the support of the Cantone Ticino: https://www4.ti.ch/decs/dcsu/pubblicazioni/artisti-dei-laghi-itinerari-europei?noMobile=1&cHash=3937c7f6b5891fa1732ac3c98292d01e. ↩︎

15. More than seventy archives were consulted. See Lucia Aliverti, “La ricerca archivistica per lo studio delle decorazioni a stucco nella Regione dei laghi,” in Felici and Jean, Stucchi e stuccatori ticinesi, 29–44. ↩︎

16. Domaso, Chiesa di San Bartolomeo, Archivio Parrocchiale, cart. “Documenti antichissimi,” ex-Matrimonialia n. 4, cart. ex-Matrimonialia: “Scrittura d’obbligo del S.re Agostino Silva per stuccare l’altare di S. Ant.o”; “Notta della spesa, che si va facendo dal s Can.co Manrico et dal can.co Passalaqua per il stucco della capella de SS. Fran.co et Antonio nella chiesa di S. Bart.meo di Domaso…” (1691–92). ↩︎

17. For the area between Lugano and Como, these volumes have proven particularly valuable: Francesco Cherubini, Vocabolario milanese-italiano (Milan: Stamperia Reale, 1839–56); Pietro Monti, Vocabolario dei dialetti della città e diocesi di Como (Milan, 1845; facs. repr., Bologna: Forni, 1984); and Vocabolario dei dialetti della Svizzera italiana (Bellinzona: Centro di dialettologia e di etnografia, 1952–). ↩︎

18. More than twenty sites and a larger number of chapels were surveyed. ↩︎

19. Luigi Brentani, Antichi maestri d’arte e di scuola delle terre ticinesi: notizie e documenti, vols. 1–4 (Como: Tipografia Emo Cavalleri, 1937–41), vols. 5–7 (Lugano: Tipografia Bianchi, 1944–63). ↩︎

20. Marta Caroselli et al., “Composition and Techniques of the Ticinese Stucco Decorations from the 16th to the 17th Century: Results from the Analysis of the Materials,” Heritage Science 8 (2020): 102. This article contains additional information about all of the scientific analyses. ↩︎

21. A Zeiss Axioskop 40 microscope coupled with a digital camera system (Axiocam) was used to document the thin sections. Images were taken using the AxioCam 4.5 software. ↩︎

22. A JEOL 6010-LA SEM–EDS (coupled with Energy Dispersive Spectroscopy microanalyses) with a backscattered electron (BSE) detector was used; images were acquired at 15.00 kV voltage and 45 and 200 × magnifications. EDS spectra and maps (K-lines) were obtained on relevant locations using the following acquisition conditions: volt 15.00 kV, process time T3, live time 90.00 s. ↩︎

23. Carla Arcolao and Alessandro Dal Bo, “L’influenza delle sostanze proteiche naturali su alcune proprietà degli stucchi,” in Biscontin and Driussi, Lo stucco, 527–38. ↩︎

24. Maria Perla Colombini and Ugo Bartolucci, “Protocollo analitico per la conoscenza dello stucco: tecniche cromatografiche e spettrometriche,” in L’arte dello stucco, conference proceedings, Campione d’Italia, November 21, 2006 (Como: New Press, 2006), 139–48. Here the presence of animal glue, casein, and egg was detected. ↩︎

25. In Valenza (Italy) soap was bought in 1633 (Chiesa di S. Maria Maggiore, Archivio Gasparolo, Scatola 12, Compagnia del SS. Sacramento, fasc. 2, Amministrazione, “Spese fatte dalla compagnia dal 1622 al 1634”); in Domaso (along Lake Como), on June 17, 1692, twenty-four eggs and soap from Venice were bought to polish the columns (Chiesa di San Bartolomeo, Archivio Parrocchiale, cart. “ex-Matrimonialia”); in Torricella (Canton Ticino) in 1718 soap was purchased probably with the same function (Archivio Parrocchiale di Torricella, “1720/1670 al 1730 / B”: “Libro dove si descrive l’entrata et uscita d’ogni anno dalli priori della Compag.a del Carmine di Torricella”). ↩︎

26. In Chiuro, on November 6, 1704, linseed oil was bought to be given to the gilders (Chiesa dei SS. Giacomo e Andrea, Archivio parrocchiale, Ro 67I5: “Libro della Scola SS.mo Rosario a Chiuro”). ↩︎

27. Stefan Zumbühl, Nadim Scherrer, and Urs Eggenberger, “Derivatization Technique to Increase the Spectral Selectivity of Two-Dimensional (2D) Fourier Transform Infrared Focal Plane Array (FT-IR FPA) Imaging: Analysis of Binder Composition in Aged Oil and Tempera Paint,” Applied Spectroscopy 68 (2014): http://doi.10.1366/13-07280; and M. Palmieri et al., “Development of an Analytical Protocol for a Fast, Sensitive and Specific Protein Recognition in Paintings by Enzyme-linked Immunosorbent Assay (ELISA),” Analytical and Bioanalytical Chemistry 399 (2011): 3011–23, http://doi.10.1007/s00216-010-4308-1. ↩︎

28. X-ray analyses were done by Thierry Radelet using an indirect digital device, with phosphorus plates (100 µm, 35 × 43 cm), which allowed levels up to 64,000 Gy. This parameter improves the performance of the plates in the case of three-dimensional objects, if compared to the analog system, because it is possible to obtain information from the different thicknesses with a single exposure, working in postproduction on the contrast of the images. The X-ray source used was Eresco 42MF 3.1, 5-200 kV and the scanner was DURR CR35 NDT. ↩︎

29. Giacinta Jean et al., “Art and Techniques of the Stuccatori: Understanding Through Replication,” in Reflecting on Reconstructions; The Role of Sources and Performative Methods in Art Technological Studies, proceedings of the ICOM-CC Working Group on Art Technological Source Research, Cologne Institute of Conservation Sciences, University of Applied Sciences, September 26–27, 2019: https://www.icom-cc-publications-online.org/4612/Art-and-techniques-of-the-stuccatori--understanding-through-replication-. ↩︎

30. This topic is thoroughly discussed in Jean and Felici, “Materials and Construction: Stuccatori at Work in Basso Ceresio; Archival Sources and Material Evidence,” in The Art and Industry of Stucco Decoration, 2025, 209-38. ↩︎

31. See, for example, the documents for the Chiesa di Sant’Eusebio, Castel San Pietro, Archivio Patriziale, “Libro dove si notta le spesse dil Comune di Castello - Libro dove si notano le spese o ricavate delli Cons.i della Comunità di Castelo S. Pietro incominciando dall’anno 1663,” payments in 1688 and 1704. ↩︎

32. See also Morbio Inferiore, Santuario della Madonna dei Miracoli, Archivio Parrocchiale, libro B, “Libro nel quale si notta entrata et spesa che si fa nella Chiesa della B. V. Maria delle Grazie di Morbio di sotto, 1665–1726,” payments in 1669. On the production of bricks at Riva San Vitale, see Sandra Eberhardt-Meli, Artigiani della terra: i laterizi in Ticino e il lavoro dei fornaciai (Locarno: Armando Dadò, 2005). ↩︎

33. Luigi Lavizzari records the kilns of Riva as firing stone “from white limestone or majolica and from dolomite, which is transported there from various parts, especially from the slopes of Monte Salvatore.” Escursioni nel Canton Ticino (Lugano: Tipografia Veladini, 1859–63; repr., Locarno: Armando Dadò, 1988), 1:117. ↩︎

34. Cherubini, Vocabolario milanese-italiano, s.v. “quadrell.” ↩︎

35. Valenza, Chiesa di Santa Maria Maggiore, Archivio Gasparolo, Scatola 12, Compagnia del SS. Sacramento, fasc. 2, Amministrazione, “Spese fatte dalla compagnia dal 1622 al 1634”, payment dated September 16, 1632. ↩︎

36. For images of profiled bricks, see Eberhardt-Meli, Artigiani della terra, 57; and Alessandro Capra, La nuova architettura civile e militare (Cremona: Pietro Ricchini, 1717; photographic repr., Bologna: Forni, 1987), 86–87. ↩︎

37. Chiuro, Chiesa dei SS. Giacomo e Andrea, Archivio Parrocchiale, Ro 67I5, “Libro della Scola SS.mo Rosario a Chiuro,” July 16 and August 5, 1698: “31 ½ lip [libbre] di ferro date per uso dello stuccatore – £ 25:4”. ↩︎

38. As per the list of irons for the Careno worksite, requested by Agostino Silva. Careno, Chiesa di Santa Maria, Archivio Parrocchiale di Pognana, uncatalogued file containing documents on the parish church of Careno, “Libro dei conti, 1668–1699 (Careno)”, note of April 15, 1684. ↩︎

39. Cherubini, Vocabolario milanese-italiano, s.v. “vergella.” Francesco Carradori, Istruzione elementare per gli studiosi della scultura (Florence: Tipografia della Società Letteraria, 1802), p. xxxvi, table XVI, n.18, lists the “Torci-Verzella: an octangular iron with an eye at one end, and that at the other twists at right angles, to receive the verzelle and exert force for bending them, and turning them in the direction needed.” ↩︎

40. See also Carradori, Istruzione elementare. More specifically, in our case studies we can mention the site of Careno (Chiesa di Santa Maria, Archivio Parrocchiale di Pognana, uncatalogued file containing documents on the parish church of Careno, “Libro dei conti, 1668–1699 (Careno)”: letter “Al M. Rev. Sig. Curato di Careno” of 1684 mentioning different materials requested by Agostino Silva); Vercana, Chiesa di S. Salvatore, Archivio Parrocchiale, Registro senza indicazioni in copertina (from 1611), February 22, 1626: “Vergiella de fero lire (libbre?) n. 5 a L 5 s.”; Domaso, Archivio Parrocchiale, cart. ex-Matrimonialia, “Notta della spesa, che si va facendo dal s Can.co Manrico et dal can.co Passalaqua per il stucco della capella de SS. Fran.co et Antonio nella chiesa di S. Bart.meo di Domaso…”, October 3, 1691; Civo, Archivio parrocchiale, “Libro dei conti”, October 3, 1695: “10 libbre vergella”, August 9, 1704: “5 tt [libbre] vergella L 4:15”; Chiuro, Archivio Parrocchiale, Ro67I5: “Libro della Scola SS.mo Rosario a Chiuro”, June 10, 1704: “lip 12 ½ vergela per uso de stucatori L 10”. ↩︎

41. The use of lime for plaster described in the technical treatises from Vitruvio to Jean-Baptiste Rondelet is well explained in Arcolao, Le ricette del restauro. On quarry areas and lime quality, see Rita Vecchiattini, La civiltà della calce: storia, scienza e restauro (Genoa: De Ferrari, 2009), 93. ↩︎

42. Arcolao, Le ricette del restauro, 4–5; and Vecchiattini, La civiltà della calce, 61. ↩︎

43. Giorgio Torraca, “Tecnologia delle malte per intonaci e della conservazione degli intonaci antichi,” in Diagnosi e progetto per la conservazione dei materiali dell’architettura, ed. Istituto centrale per il restauro (Rome: De Luca, 1998), 205. Recent research has confirmed that seasoned lime has better mechanical properties and is more workable. Elena Pecchioni, Fabio Fratini, and Emma Cantisani, Le malte antiche e moderne tra tradizione e innovazione (Bologna: Patron, 2008), 37–38. ↩︎

44. Cherubini, Vocabolario milanese-italiano, s.v. “sabbione.” ↩︎

45. Castel San Pietro, Archivio patriziale, cappella del SS. Crocifisso, “Libro dei conti”, 1688. ↩︎

46. Valenza, Chiesa di Santa Maria Maggiore, Archivio Gasparolo, Scatola 12, Compagnia del SS. Sacramento, fasc. 2, Amministrazione, “Spese fatte dalla compagnia dal 1622 al 1634.”. Ordinary sand cost 16 lira, including transport; the cost of transport had significant bearing, considering that sand was usually inexpensive; red sand costs 11 lira (5 lira for the material and 6 lira for transport), and granite sand 1 lira. ↩︎

47. On the use of gypsum, see Jean et al*., “Art and Techniques”; Marta Caroselli et al.*, “Gypsum in Ticinese Stucco Artworks of the 16–17th Century: Use, Characterization, Provenance and Induced Decay Phenomena,” Journal of Archaeological Science: Reports 24 (2019): 208–19; and Caroselli et al., “Composition and Techniques.” ↩︎

48. Leon Battista Alberti recommended crushing and grinding old ropes minutely if working a stucco when it is very hot so that water evaporates less easily from the mortar. De re aedificatoria, ed. Giovanni Orlandi and Paolo Portoghesi (Milan: Il Polifilo, 1966), book 6, chap. 9, 285. ↩︎

49. A record for Chiavenna (Archivio capitolare della Collegiata di San Lorenzo) notes the purchase of “stones to make powder to give white to the stucco.” Marble is pounded in a stone mortar, then sifted finely and mixed with lime in the ratio of two-thirds lime to one-third marble powder. Giorgio Vasari, Le vite de’ più eccellenti architetti, pittori, et scultori italiani, da Cimabue, insino a’ tempi nostri, ed. Luciano Bellosi and Aldo Rossi (1550; repr., Turin: Einaudi, 1991), chap. 4, 37, and chap. 13, 37, 55–56. This recipe was repeated by several following authors like Sansovino, Cataneo, Zanini, Félibien (see Arcolao, Le ricette del restauro). ↩︎

50. Domaso, Archivio Parrocchiale, cart. ex-Matrimonialia, “Notta della spesa, che si va facendo dal s Can.co Manrico et dal can.co Passalaqua per il stucco della capella de SS. Fran.co et Antonio nella chiesa di S. Bart.meo di Domaso…”, supply of November 20, 1691. ↩︎

51. The presence of original gilding on stucco decorations, not compromised by multiple restorations, is very rare. ↩︎

52. For a detailed technical description of many stucco decorations in Canton Ticino, see https://restadistucco.ch/en. ↩︎

53. The research project ERASMUS+ KA220-HED, “Stucco Decoration across Europe (STUDEC)”, no. 2022-1-CZ01-KA220-HED-000085652, is based on this methodological approach. It is being carried out in collaboration with Jana Zapletalová (Palacký University, Olomouc [CZ]), Serena Quagliaroli (Università degli Studi di Torino [IT]), Michał Kurzej (Jagiellonian University [PL]), and Jan Válek (Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, Prague [CZ]). ↩︎