An approach to the study of the fungal deterioration of a classical art material: Mastic varnish

Romero-Noguera, Julio; López-Miras, María del Mar; Martín-Sánchez, Inés; Ramos-López, José Miguel; Bolívar-Galiano, Fernando

doi:10.2225/vol13-issue6-fulltext-11

Cited by 6 publications

(4 citation statements)

References 12 publications

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“…Its main purposes in a work of art are for protection and esthetics [23]. The natural varnishes traditionally used in painting are terpenoids, which undergo oxidation processes and other chemical changes that cause them to yellow and lose mechanical and optical properties [24][25][26][27]. One of the most frequent painting restoration tasks is to remove aged varnishes by using solvents and replace them with polymeric varnishes, generally acrylics, which are much more stable.…”

Section: The Varnish Layermentioning

confidence: 99%

Response Surface Model Applied to Fine Arts: The Case of the Restoration of Paintings

Romero-Noguera¹,

Pérez-Villares²,

Bolívar-Galiano³

et al. 2023

Response Surface Methodology - Research Advances and Applications

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Cleaning polychrome paintings and sculptures is an essential task in restoration treatment, since it irreversibly affects the appearance and material structure of such works of art. It is a completely “analogical” process consisting of removing surface dirt, aged varnishes or repainting (paints added to the original) based on the restorer’s experience and knowledge, as well as on different internationally accepted criteria for such interventions. In this chapter we are presenting an example of the adaptation of the response surface model to this field, which is complex and difficult to adapt to quantitative parameters and has never before been studied with this approach. Using the MODDE Go® experiment optimization and statistical design software, the effectiveness of cleaning pictorial works of art has been studied using various formulas composed mainly of water and a low-toxicity monoterpene: limonene. The model’s statistical validity is demonstrated, as well as its ability to determine the main factors that affect the cleaning by means of different responses (methods) to evaluate its effectiveness: an expert’s opinion using visible light and ultraviolet light, the amount of varnish removed using gas chromatography coupled with mass spectrometry, and the effects on color, lightness and gloss. The main influential factors were the concentrations of the two main components of the proposed formulations, water and limonene, which regulate the cleaners’ level of hydrophilia and lipophilicity, followed by the types of pigments and type of varnish used, and aging. Using an in silico simulation, the proposed model also enables specific compositions to be formulated for different scenarios and cleaning applications that are potentially effective and harmless to the pictorial materials and the restorers’ health.

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Section: The Varnish Layermentioning

confidence: 99%

Response Surface Model Applied to Fine Arts: The Case of the Restoration of Paintings

Romero-Noguera¹,

Pérez-Villares²,

Bolívar-Galiano³

et al. 2023

Response Surface Methodology - Research Advances and Applications

Self Cite

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“…The microorganisms listed here were selected on the basis of their capacity for growing and causing chemical changes in resins, as reported in earlier works [30][31][32][33]. Francis of Assisi (anonymous), both from the 17th century and are severely affected by biodeterioration processes (Figure 1).…”

Section: Microorganismsmentioning

confidence: 99%

“…The microorganisms listed here were selected on the basis of their capacity for growing and causing chemical changes in resins, as reported in earlier works [30][31][32][33].…”

Section: Microorganismsmentioning

confidence: 99%

“…Penicillium and Aspergillus are the most commonly described fungi associated with biodeterioration in polychrome artworks, and the genus Bacillus and Arthrobacter among bacteria [25][26][27][28][29]. Biodeterioration of these materials has been studied in past publications, which have described different analytical markers for these processes [30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

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Varnishes with Biocidal Activity: A New Approach to Protecting Artworks

2020

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Keeping agents that cause biodeterioration under control is a common task in restoring and conserving artworks. However, there are very few studies, specifically those concentrating on pictorial works, that provide solutions compatible with the complex mix of organic and inorganic materials to be found in such cultural assets. This study aims to use biocide products that are commonly used in this field (benzalkonium chloride, o-phenylphenol, and tributyltin naphthenate) and which are associated with natural varnishes with a long tradition in artistic practices, in order to protect paintings and polychrome sculptures from environmental fungi and bacteria without altering the original materials or the visual appearance of the artworks. The effectiveness or innocuousness of the treatments was tested chemically and visually via optical microscopy, gas chromatography–mass spectrometry (GC-MS), and a multidimensional scaling analysis (MDS); the treatments produced good results as regards the inhibition of microbial growth and scarce interaction with the artistic materials being studied.

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Photoreactivity of Oil and Alcoholic Diterpenic Varnishes: Key Role of the Polymerization Process

et al. 2020

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The conservation of artworks is a key issue in cultural heritage. The alterations of the varnish could be linked mainly to the photopolymerization of the natural resin. The photodegradation of sandarac and rosin under simulated solar light was studied using a multianalytical approach using a second derivative FT‐IR spectroscopy and gas chromatography coupled to mass spectroscopy. In all resins, main terpene molecules underwent esterification and perestererifications via the formation of hydroperoxides preferentially formed on tertiary carbons. This polymerization could be associated with the advice of important art manuals and treatises recommending exposing varnishes to the sunlight while drying. In a second step, these esters and perester bonds underwent photoscissions by Norrish I and II reactions, leading to the production of free terpenes in the varnishes. In sandarac varnishes, the vinyl bonds showed a strong reactivity associated with the formation of trans and cis secondary alkenes. These photochemical reactions could explain an important part of the problem of conservation of the varnish layers experienced by museums all over the world.

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An approach to the study of the fungal deterioration of a classical art material: Mastic varnish

Cited by 6 publications

References 12 publications

Response Surface Model Applied to Fine Arts: The Case of the Restoration of Paintings

Response Surface Model Applied to Fine Arts: The Case of the Restoration of Paintings

Varnishes with Biocidal Activity: A New Approach to Protecting Artworks

Photoreactivity of Oil and Alcoholic Diterpenic Varnishes: Key Role of the Polymerization Process

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