<i>Gessoes</i> in Portuguese Baroque Gilding Grounds: Part 2: Analytical Study of Historical Samples and Archaeological Reconstructions

Cardoso, Isabel Pombo; Pye, Elizabeth

doi:10.1080/00393630.2016.1266430

Cited by 4 publications

(5 citation statements)

References 25 publications

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“…In line with the preparatory technique of that time, a different distribution of calcium sulphate dihydrate and anhydrite mineral phases was observed within the distance from the surface. Anhydrate (gesso grosso) was found mainly in the bulk of the ground, whereas calcium sulphate dihydrate (gesso sottile) was found closer to the metal layers as a kind of white bole layer [34][35][36]. This result further corroborates the execution of the water gilding technique, where the use of a white ground bole served the purpose to burnish the applied Ag leaf.…”

Section: Discussionsupporting

confidence: 69%

“Argento Deaurato” or “Argento Biancheggiato”? A Rare and Interesting Case of Silver Background in Italian Painting of the XIII Century

et al. 2020

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The painting depicting the “Virgin with the Child and two angels” by a Tuscan anonymous artist of the XIII century, has raised great interest regarding the execution technique including the use of silver, applied on wood as a background. An in-depth investigation was carried out especially concerning the burnishing process of the silver leaves as well as a detailed inspection of the nature of the organic compounds over the metal leaf and the degradation products of the silver layer. To this aim, a multianalytical approach was used including UV–VIS microscopy along with an Ultra-High-Resolution Scanning Electron Microscopy (UHR-SEM), as well as Fourier Transform Infrared (FTIR), fluorescence and micro-Raman spectroscopies. As a result, the presence of an oil-resin varnish layer in the uppermost layer and a wax-protein layer between the varnish and the metal layer as well as the evidence that the silver leaf was applied with high accuracy directly to the preparation layer, were clearly demonstrated. Furthermore, degradation products of the silver leaf were identified as sulphides, chlorides, and oxides. The holistic approach herein adopted enabled a step forward in the knowledge of the 13th century silver leaf gilding technique, adding value to the originality of this artwork. In this respect, the scientific evidence led to the assumption that likely this painting originally showed a silver-colored background (“argento biancheggiato”) as compared to the initial theory of a case of “argento deaurato”.

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Section: Discussionsupporting

confidence: 69%

“Argento Deaurato” or “Argento Biancheggiato”? A Rare and Interesting Case of Silver Background in Italian Painting of the XIII Century

et al. 2020

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“…This double-layered ground is then covered with a bole layer (a fine coloured clay). The whole forms a composite system with gradually finer and smoother particles, which provides an extremely smooth surface onto which the gold leaf is applied and burnished to produce a shiny gilded surface simulating solid gold [1][2].…”

Section: Brief Description Of Gilding Gesso Groundsmentioning

confidence: 99%

“…This particle shape and size also increases the plasticity of the paste, improving its workability; it speeds the carbonation rate, as well as increasing the final strength of the mortar [6,[79][80]. The slaking process is also used for producing gesso mate powders in order to achieve extremely small and lamellar gypsum particles which have a vital impact on quality and durability of gilded and polychrome surfaces, although through different mechanisms [2][3][4].…”

Section: Evidence Of Transference Of Practicesmentioning

confidence: 99%

“…However, this cannot be considered as the only reason since there is some gypsum in Portugal (though grey), and access to natural gypsum was possibleas nearby countries, with known commercial contacts, have good gypsum rock supplies (Spain, France and Morocco). Furthermore, there is documentary and analytical evidence of the extensive use of gypsum as the raw material for the gesso grounds since the 13th century [1][2].…”

Section: The Curious Case Of the Use Of Gypsum Plaster In Portugalmentioning

confidence: 99%

“…These southern European gilding grounds, gesso grounds, are commonly made of gypsum based materials (as aggregates) mixed with size glue (as binder) and typified by a double-layered structure. These materials and practices used to produce them were clearly aimed at obtaining long lasting and high quality gilded surfaces due to the importance of these religious objects [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

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Preparing the foundation for stable gilding: the origins of materials and practices – a review

Cardoso

2019

Cons. Património

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This paper is the fifth of a series and focuses on tracing the history of the use of gypsum based products as well as of the use of ground layers, centred on a review of published analytical evidence. The purpose is to contribute for the understanding of these long traditions which led to the choice of specific materials and practices used for producing gilding grounds in southern Europe. In fact, several practices and the raw material gypsum used in gilded surfaces do have an extremely long tradition, which can be traced back to the Pre-Pottery Neolithic B. The systematic use of these materials, especially the use of ground layers for decoration and other purposes, suggests not only an intention but also, somehow, the notion of a complex concept, the concept of a composite material, even at these very early periods, from which gilding origins. In addition, the particular case of Portugal shows that aspects such as religious, political, and sociocultural influences played a central role in the choice of gypsum as the raw material, which was curiously used exclusively for gilding. Resumo Este artigo, o quinto de uma série, explora a história da utilização do gesso e de camadas de preparação, baseado numa revisão de literatura com evidência analítica. O objectivo é contribuir para a compreensão destas longas tradições que estão na génese da escolha de materiais e de práticas específicas utilizadas para produzir camadas de preparação de douramento no sul da Europa. De facto, a utilização do gesso como matéria-prima bem como de certas práticas, associadas à produção de superfícies douradas, tem uma tradição extremamente longa identificando-se já no Neolítico Pré-cerâmico B. O uso sistemático desses materiais, especialmente na produção de camadas de preparação, para decoração ou outros propósitos, indiciam não só uma intenção mas também, de alguma forma, a noção de um conceito complexo, o conceito de material compósito, mesmo nestes períodos tão remotos. Por outro lado, o caso particular de Portugal revela que razões religiosas, políticas, assim como influências socioculturais, desempenharam um papel central na escolha do gesso como matéria-prima, curiosamente utilizado em exclusivo no douramento.

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Manufacturing Technique and Conservation Treatment of a Unique Gilt-Bronze Statuette Excavated Through Restoration of the Step Pyramid, Saqara

MAHMOUD¹,

EWAIS

MOHAMED

2021

EJMSE

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Unexpected excavation of the Osirian statuette was inaugurated in 2021 during a conservation project at the first step in the western façade of King Djoser Pyramid which dates back to the Ptolemaic era. Varies strategies of the examination techniques, such as stereo and polarizing microscopes, and scanning electron microscopy coupled to energy dispersive X-ray spectrometry and X-ray diffraction were undertaken to characterize the chemical structure of gilt-layer, preparatory layer, and bronze alloy to evaluate their condition. This paper describes the actual condition of the statuette after excavation inside the King Djoser Pyramid, and characterization of the corrosion phases, and determines the best technique for conservation. Visual investigation revealed that the core of the bronze statuette was in good condition, but most gold with gesso was misplaced. Investigation and analyses results demonstrate that amazing technique which gilding has been accomplished as a thin layer over the white substrate from gesso. X-ray diffraction establishes that cuprite and atacamite resulting from the activation corrosion were the major minerals covering the statuette. Besides, calcite and gypsum were detected, which are to be a part of the preparatory layer. EDX results demonstrate that pure gold was likely used in the gilding layer. The gilt-bronze statuette was made of multi-layered surfaces. The solid cast was used in the crafting technique. Fixation of remaining plaster to metal was undertaken using Clucel G (4%). The figure was immediately treated via popular methods as mechanical tools and solvents. Benzotriazole inhibitor (3%) was used to cure the activation of bronze disease. The coating system was applied by using 3% paraloid B72. Finally, the statuette was preserved in the storage with the appropriate conditions.

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Gessoes in Portuguese Baroque Gilding Grounds: Part 2: Analytical Study of Historical Samples and Archaeological Reconstructions

Cited by 4 publications

References 25 publications

“Argento Deaurato” or “Argento Biancheggiato”? A Rare and Interesting Case of Silver Background in Italian Painting of the XIII Century

“Argento Deaurato” or “Argento Biancheggiato”? A Rare and Interesting Case of Silver Background in Italian Painting of the XIII Century

Preparing the foundation for stable gilding: the origins of materials and practices – a review

Manufacturing Technique and Conservation Treatment of a Unique Gilt-Bronze Statuette Excavated Through Restoration of the Step Pyramid, Saqara

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