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See detailDistinction by micro-Raman spectroscopy and chemometrical analysis of copper phthalocyanine blue polymorphs in oil-based and acrylic samples
Defeyt, Catherine ULg; Van Pevenage, Jolien; Learner, Tom et al

in Van den berg, K.J.; Burnstock, A.; de Tagle, A. (Eds.) et al Issues in Contemporary Oil Paints (2014)

Copper phthalocyanine (CuPc) blue, commonly named phthalo blue is the most important synthetic organic blue pigment in the 20th and 21st century artists paints. Phthalo blue, which is adopted by artists ... [more ▼]

Copper phthalocyanine (CuPc) blue, commonly named phthalo blue is the most important synthetic organic blue pigment in the 20th and 21st century artists paints. Phthalo blue, which is adopted by artists since 1936, is a polymorphous pigment. Currently, the alpha, beta and epsilon CuPc polymorphs are used in artists paint formulations. The identification of the CuPc crystal form provides technical and chronological information relevant for studying artworks. Raman Spectroscopy (RS) is a very valuable technique for the detection of phthalo blue in paint layers. However, the spectral interpretation is not straightforward concerning the CuPc polymorph distinction. To overcome the problem we have previously developed a procedure combining RS and chemometrical analysis. The experimental results that we obtained have demonstrated its efficiency for predicting the CuPc crystal form in unknown paint samples. In the present work, this procedure was applied on oil-based and acrylic paints from Sam Francis’ studio and the Getty Conservation Institute (GCI) Reference Collection. [less ▲]

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See detailAnalytical study of “La Famille Soler” by Picasso: from the Blue Period to Cubism
Defeyt, Catherine ULg; Vekemans, Bart; Vandenabeele, Peter et al

Poster (2013, September 23)

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See detailCopper phthalocyanine blue pigments in conservation
Defeyt, Catherine ULg

Doctoral thesis (2013)

The phthalocyanine family, and more specifically the copper phthalocyanines (CuPcs) are the most important blue and green artists’ pigments from the end of the 20th century. This thesis focuses on the ... [more ▼]

The phthalocyanine family, and more specifically the copper phthalocyanines (CuPcs) are the most important blue and green artists’ pigments from the end of the 20th century. This thesis focuses on the CuPc blue pigments used in the artists’ paint formulations. CuPc blue extensive use as modern artists’ pigment and its implications in conservation science are pointed out. Their discovery, chemical composition, molecular structure and general properties are also reviewed. Additionally, the polymorphism and the influence of the crystal form on the final properties of the phthalo blue pigments are discussed. A methodology using non-destructive techniques and statistical analysis is then presented. This new procedure allows the identification of the CuPc crystal form in paint layers and is suitable for artwork analysis. Some CuPc polymorphs are prone to crystallization defects in presence of aromatic solvents, leading to a reduction of color strength and a shift in hue. Crystallization resistance of the CuPc polymorphs has then been assessed by means of crystallization tests performed on dry pigments and on paint films. Case studies are then presented. La famille Soler by Picasso has been studied by imaging and non-invasive analytical techniques. The successive underlying compositions have been revealed and the pigments used for the different compositions have been characterized. Then micro-samples taken from Delvaux’s paintings and Francis and Lichtenstein’s studio paints have been analyzed to characterize the blue pigments preferred by these artists. The crystal form of the phthalo blue pigments identified from four micro-samples taken from two Léger and Pechstein fake paintings have been investigated as well. Finally, the historic phthalo blue samples from the Getty Conservation Institute Reference Collection have been studied. [less ▲]

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See detailPB15’s discrimination in oil paintings by non-destructive methods
Defeyt, Catherine ULg; Vandenabeele, Peter; Van Pevenage, Jolien et al

Poster (2013, March 29)

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See detailPB15 polymorphic distinction in paint samples by combining micro- Raman spectroscopy and chemometrical analysis
Van Pevenage, Jolien; Defeyt, Catherine ULg; Moens, Luc et al

Poster (2013)

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See detailMicro-Raman spectroscopy and chemometrical analysis for the distinction of copper phthalocyanine polymorphs in paint layers
Defeyt, Catherine ULg; Van Pevenage, Jolien; Moens, Luc et al

in Spectrochimica Acta Part A : Molecular and Biomolecular Spectroscopy (2013), 115

In art analysis, copper phthalocyanine (CuPc) is often identified as an important pigment (PB15) in 20th century artworks. Raman spectroscopy is a very valuable technique for the detection of this pigment ... [more ▼]

In art analysis, copper phthalocyanine (CuPc) is often identified as an important pigment (PB15) in 20th century artworks. Raman spectroscopy is a very valuable technique for the detection of this pigment in paint systems. However, PB15 is used in different polymorphic forms and identification of the polymorph could retrieve information on the production process of the pigment at the moment. Raman spectroscopy, being a molecular spectroscopic method of analysis, is able to discriminate between poly- morphs of crystals. However, in the case of PB15, spectral interpretation is not straightforward, and Raman data treatment requires some improvements concerning the PB15 polymorphic discrimination in paints. Here, Raman spectroscopy is combined with chemometrical analysis in order to develop a procedure allowing us to identify the PB15 crystalline structure in painted layers and in artworks. The results obtained by Linear Discriminant Analysis (LDA), using intensity ratios as variables, demonstrate the ability of this procedure to predict the crystalline structure of a PB15 pigment in unknown paint samples. [less ▲]

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See detailAutomatic X-ray fluorescence scanning mobile system for 2D chemical analysis
Strivay, David ULg; Hocquet, François-Philippe; Dister, Hervé et al

Conference (2012, December)

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See detailContribution to the identification of α-, β- and ε-copper phthalocyanine blue pigments in modern artists' paints by X-ray powder diffraction, attenuated total reflectance micro-fourier transform infrared spectroscopy and micro-Raman spectroscopy
Defeyt, Catherine ULg; Vandenabeele, P.; Gilbert, Bernard ULg et al

in Journal of Raman Spectroscopy (2012), 43

Since the end of the 20th century, the α-, β- and ε-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide ... [more ▼]

Since the end of the 20th century, the α-, β- and ε-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide useful technical and chronological information for the study of works of art. Although when a CuPc blue pigment is identified, its crystalline structure often remains unspecified despite the interest for conservation science. In this study, X-ray powder diffraction, attenuated total reflectance micro-Fourier transform infrared spectroscopy and micro-Raman spectroscopy analyses have been carried out on 15 dry pigment samples of CuPc and acrylic, vinylic, alkyd, arabic gum and oil-based artists' paints. By using the polymorphic markers underlined for dry pigments, the CuPc crystalline structure has been successfully identified for most of the analysed artists' paints. However, according to the analytical technique used and the investigated paint sample, the obtained results largely differ. © 2012 John Wiley & Sons, Ltd. [less ▲]

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See detailThe influence of aromatic solvents on CuPC blue pigments in oil paintings
Defeyt, Catherine ULg; Wijnberg, Louise; Verbeeck, Muriel ULg et al

Poster (2011)

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See detailThe Influence of aromatic solvents on CuPc blue pigments
Defeyt, Catherine ULg; Vandenabeele, Peter; Lycke, Sylvia et al

Poster (2011)

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See detailExploration des fonds : La famille Soler de Pablo Picasso
Defeyt, Catherine ULg

in CeROArt : Conservation, Exposition, Restauration d'Objets d'Art (2011), 6

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See detailCompte rendu de Restauration et non-restauration en art contemporain 2
Defeyt, Catherine ULg

in CeROArt : Conservation, Exposition, Restauration d'Objets d'Art (2010), 5

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See detailFuture Talks, Compte-rendu du colloque organisé par Die Neue Sammlung, The International Design Museum, les 22 et 23 octobre 2009 à Munich
Defeyt, Catherine ULg

in CeROArt : Conservation, Exposition, Restauration d'Objets d'Art (2010)

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See detailModifications optiques du bleu de phtalocyanine de cuivre en présence d’hydrocarbures aromatiques : problématiques en conservation-restauration d’œuvres d’art
Defeyt, Catherine ULg

in Actes des 13es journées d’études de la SFIIC, Art d’aujourd’hui patrimoine de demain,conservation et restauration des oeuvres contemporaines (2009)

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See detailCompte-rendu de Restauration et non-restauration en art contemporain sous la direction de Marie-Hélène Breuil, ARSET, 2008
Defeyt, Catherine ULg

in CeROArt : Conservation, Exposition, Restauration d'Objets d'Art (2009), 3

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