Peer Reviewed: Clarifying the Haze: Efflorescence on Works of Art

Ordonez, Eugena; Twilley, John

doi:10.1021/ac971692l

Cited by 30 publications

(20 citation statements)

References 8 publications

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“…A few cases of potassium and calcium soaps have been reported as well (Boon, private communication). In addition to the 'protrusion' phenomena, metal soaps were found to be associated with many other degradation phenomena: for example, efflorescences (Ordonez & Twilley, 1997), darkening due to increased transparency (Noble et al, 2005), delamination (Helou-de La Grandiere et al, 2008) exudates and drips (Boon & Hoogland, 2014), cracks (Duffy et al, 2014), among others. Most current studies highlight degradation phenomena associated with the presence of metal soaps in cultural heritage.…”

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confidence: 99%

Lead soaps in paintings: Friends or foes?

Cotte

Checroun

Nolf

et al. 2016

Studies in Conservation

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The origin(s) and role(s) of metal soaps in paints are a worldwide concern today. These hybrid compounds, containing both fatty acid chains and metals associated with a carboxylate function, are increasingly identified in paints. As reviewed in the first part of this work, the presence of metal soaps in paints is differently interpreted in scientific publications: metal soaps are sometimes considered to play a positive role as anchor points, during paint drying processes; they can also be considered as responsible for many degradation processes (protrusions, efflorescences, darkening, etc.). Their origins are also interpreted in various ways. In some paintings (in particular from the twentieth century), they have sometimes introduced on purpose, as additives, to modify the physical properties of the painting materials. In older paintings, metal soaps are usually thought to result from an uncontrolled reaction of oil with lead-based pigments, in particular lead white, red lead, and lead tin yellow. In the second part of this work, the review of historical recipes of lead-based paint shows an important number of recipes based on controlled mixing of oil with lead driers. In the third part, the experimental reproduction of such traditional recipes using walnut oil and litharge (PbO) shows that lead soaps can be formed, both in about one hour at ∼100°C, or in about one month at room temperature. It shows as well that after a few years, litharge is no longer detected in the paint medium, while different lead carbonates are. Finally, the micro-infrared spectroscopy and micro-X-ray diffraction re-analysis of protrusions from a nine-year model painting shows together with lead soaps, the presence of Pb 5 (CO 3 ) 3 (OH) 2 O ('synthetic plumbonacrite'), an unusual phase recently observed in a protrusion from a painting by Vincent Van Gogh. This work highlights (i) the multiple origins and roles of metal soaps in paints and (ii) the importance of combining the analysis of fragments from historical paintings with the analysis and reproduction of historical recipes. In particular, we show that the components detected today in historical paintings may severely differ from those originally used or prepared by the painter, complicating the assessment of the painter's intentions. More than the presence of metal soaps, the key questions to be tackled should be about their origins and (re)mobilization.

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confidence: 99%

Lead soaps in paintings: Friends or foes?

Cotte

Checroun

Nolf

et al. 2016

Studies in Conservation

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“…Tanto substâncias líquidas como sólidas podem migrar através de um filme de tinta [25][26][27][28][29] . Como a atividade dos microbicidas sugeriu a sua presença numa camada bem superficial da tinta, foi realizada a análise PAS, que, por suas características, já descritas, examina uma camada bem fina da superfície dos materiais, especialmente em maiores velocidades.…”

Section: Resultsunclassified

Análise por FT-IR (UATR E PAS) de microbicidas em filmes poliméricos de tintas comerciais

et al. 2014

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Resumo: Este trabalho mostra a avaliação de duas técnicas de espectroscopia no infravermelho por transformada de Fourier (FT-IR), Universal Reflexão Total Atenuada (UATR) e Detecção Fotoacústica (PAS), para a caracterização dos microbicidas, OIT, carbendazim e diuron, mais comuns em tintas acrílicas imobiliárias, levando-se em conta as características de cada técnica de análise de superfície tal como a profundidade de amostragem, sob o aspecto qualitativo. A análise PAS, utilizando-se a velocidade de 0,20 cm.s -1 , mostrou-se a única adequada ao estudo. A presença dos microbicidas na película de tinta seca foi, também, confirmada por meio de análises microbiológicas e HPLC. Palavras-chave: Tintas, microbicidas, FT-IR, UATR, PAS. Analysis by FT-IR Techniques (UATR and PAS) of Microbicides in Polymeric Films of Commercial PaintsAbstract: This paper shows the evaluation of two Fourier transform infrared spectroscopy techniques (FT-IR), Universal Attenuated Total Reflection (UATR) and Photoacoustic Detection (PAS), for the characterization of the microbicides OIT, carbendazim and diuron, which are used in acrylic paint formulations. We considered the characteristics of each surface analysis technique, such as sampling depth. The PAS analysis, using the speed of 0.20 cm.s -1 , proved to be the only technique suitable for the study. The presence of the referred microbicides in the dried paint film was also confirmed by microbiological and HPLC analyses. Keywords: Paint, microbicides, FT-IR, UATR, PAS. IntroduçãoMateriais de recobrimento, como as tintas, contêm água, dispersões poliméricas, pigmentos, cargas, modificadores reológicos, aditivos e outros ingredientes. São, potencialmente, suscetíveis ao ataque microbiológico no seu estado úmido e precisam ser preservados com produtos químicos, denominados microbicidas, popularmente designados biocidas, atuando neste caso, especificamente, como preservantes ou conservantes [1] . Atualmente, recobrimentos arquitetônicos interiores são os materiais com maiores demandas e restrições ambientais e toxicológicas para os preservantes, e isso explica porque tão poucas moléculas são usadas para a preservação de tintas e em tão baixas concentrações quanto possível, geralmente <1% [2] .Os microbicidas são produtos incorporados às tintas, cuja função é protegê-las, tanto no estado úmido quanto no estado seco, visando à inibição do crescimento de microrganismos (ou sua morte), garantindo maior durabilidade às tintas e aos filmes secos [1,3,4] . São classificados conforme seu uso, sendo conhecidos como fungicidas, bactericidas e algicidas. Existem no mercado cerca de 250 diferentes microbicidas, destinados à proteção da tinta na lata e do filme aplicado [5] . Os fungicidas 2-methoxicarbonilamino-benzimidazol (carbendazim), 2-N-octil-4-isotiazolin-3-ona (OIT) e o algicida N'-(3,4-diclorofenil)-N,N-dimetilurea (diuron) são os microbicidas mais populares no mercado brasileiro para a preservação do filme seco.Devido a sua alta toxicidade para fungos, o OIT é usado, principalmente, como um ...

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“…[3][4][5][6] The TFA was applied to a data matrix, consisting of the recorded spectra of the mixtures (binary and ternary) in the 4000-370 cm -1 region.…”

Section: Resultsmentioning

confidence: 99%

“…Conservation treatment of these objects is highly dependent on well-established knowledge of the salts present in the efflorescence. [6][7][8][9] On the other hand, identified salts could indicate the origin of the efflorescence as well as the degree of degradation processes.…”

Section: Introductionmentioning

confidence: 99%

Characterization of salt efflorescence using target factor analysis. Development of the method

Kuzmanovski

1997

J. Braz. Chem. Soc.

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Usando-se análise fatorial TFA (target factor analysis), tentamos desenvolver um método simples e prático para determinar a composição de sais na eflorescência de pinturas de parede, conveniente para o uso no trabalho diário de restauradores. O desenvolvimento do modelo TFA para determinação qualitativa da composição de depósitos de sais nas pinturas de parede é baseado no uso de um banco de dados de espectros de infravermelho das substâncias encontradas na eflorescência. Para isto, vinte espectros de infravermelho de substâncias encontradas comercialmente foram registrados, formando o banco de dados. A análise fatorial (TFA) foi então aplicada para determinar a composição qualitativa dos sais. O procedimento foi testado inicialmente em diferentes misturas artificiais dos sais, binárias e ternárias, mimetizando a eflorescência encontrada nas pinturas de paredes. Como TFA mostrou bons resultados nas misturas preparadas, o mesmo procedimento foi aplicado com sucesso na determinação da composição qualitativa de amostras de sais coletados de duas igrejas na República da Macedônia. Os resultados obtidos confirmaram que o procedimento proposto é adequado para estes tipos de análises.An attempt is made, using target factor analysis (TFA), to develop simple and practical approach in determining the composition of the salts in efflorescence of the wall paintings, convenient for use in daily work of conservators. The development of the TFA model for determination of qualitative composition of salts deposits on the wall paintings is based on the use of infrared spectra database of substances found in the efflorescence. For this purpose, a total number of twenty infrared spectra of commercially available substances were recorded, setting the database. The target factor analysis was then applied in order to determine the qualitative composition of the salts. The procedure was first tested on different artificial, binary and ternary mixtures of salts, mimicking the efflorescence found in the wall paintings. Since the TFA showed good results on the prepared mixtures, the same procedure was successfully applied in determining the qualitative composition of salt samples collected from two churches in Republic of Macedonia. The obtained results confirmed that the proposed procedure is suitable for these types of analyses.

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Peer Reviewed: Clarifying the Haze: Efflorescence on Works of Art

Cited by 30 publications

References 8 publications

Lead soaps in paintings: Friends or foes?

Lead soaps in paintings: Friends or foes?

Análise por FT-IR (UATR E PAS) de microbicidas em filmes poliméricos de tintas comerciais

Characterization of salt efflorescence using target factor analysis. Development of the method

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