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Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected] © 2013 - www.ciram-art.com PAINTING STUDY Imaging, Chemical analysis, dating

CIRAM Scientific Study of Paintings - 2013

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CIRAM leaflet to understand how we can scientifically test paintings for authentication purpose.

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Page 1: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

PAINTING STUDY Imaging, Chemical analysis, dating

Page 2: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

OBJECTIVES The scientific analysis of a painting answers various concerns:

- Characterization of the pictorial techniques, - Attendance at the restoration/preservation of the works of art, - Falsifications research…

The results obtained come as a complement of a stylistic expertise. The analysis brings objectives data essential to the knowledge of the work of art such as:

- Research of a signature, - prominence of underlying drawings, - visualization of pentiments, - identification of restorations, - characterization of the different materials used, - dating of the support (canvas, wood, paper,…)

Our work is the object of a critical synthesis report gathering all the photographic documentation and the complementary analysis results.

CIRAM promises to answer these problematics in the strict respect of a rigorous scientific reasoning.

MEANS IMPLEMENTED Imaging in raking light This study is realised with a powerful halogen lamp, diffusing a cold light. The shootings are realised thanks to a digital camera. This method of observation of the work of art underlines all the asperities of the surface and the reliefs (cracks, eventual upheavals or sinkings of the pictorial substance). It permits to characterize the state of preservation of the varnish and of the paintings grounds, the presence of deteriorations and of eventual restorations.

Views of detail, in raking light. The areas surrounded by dotted lines seem to present a nexus of superficial crackings denser than on the rest of the painting. Oil painting, Fine arts museum of Pau.

Page 3: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

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Views of details, in raking light. The area is characterized by long regular crackings. Besides, we observe lines marked along the right arm, at the level of the head and between the wing and the left arm (arrows). It could suggest the presence of pentiments. Oil painting, Fine arts museum of Pau.

Page 4: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

Image in Ultra-Violet spectra The luminous source used for this study is constituted by a whole of neon lights lighting up in the ultra-violet (black light). The shootings are realised thanks to a digital camera. They permit to present the whole work of art and detailed areas. This method of observation of the surface of the canvas makes particularly visible the surpaints of surface present over the varnish. Indeed, the lighting used engenders the fluorescence of the materials constituting the varnish in a visible way depending on their age. The fluorescence variations make appearing a relative chronology between different moments associated to modifications of the surface of the work of art.

Infrared reflectography (IR) The shots can be performed in the spectral range of the infrared, using the OSIRIS camera, the latest generation High Definition IR system. The images are immediately available on multiple media types (laptop, screen, projector, tablet...). Infrared reflectography generally permits to reveal underlying drawings, pentiments and eventual surpaints. A hidden signature or any other writing invisible to the naked eye can also be searched with this approach.

Views of detail, in white light (left) and in infrared reflectography (right). This method of imaging underlines the sharpness of the underlying drawing of the eyebrows. Oil painting, private collection.

Views of detail, in natural lighting and ultra violet spectra. We observe a dark transversal band and different fluorescence areas corresponding to restoration points having required a re-varnishing located and/or the use of pigments different from those employed initially. Oil painting, private collection.

CIRAM uses the Osiris IR camera.

Page 5: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

X-Ray radiography imaging The X-Rays, of high energy, penetrate all the layers of painting and of preparation of the canvas and permit to obtain an image of the repartition of the materials according to their density. X-ray radiography also permits to appreciate the preservation state of the work of art showing restoration areas, underlined by discontinuities in the image. Besides, it constitutes an efficient tool to characterize the presence of pentiments and surpaints. The important flexibility of our equipment permits to analyse in situ works of art of all dimensions. Then, digital images are treated in negative, to emphasize the contrasts and to facilitate the underlining of eventual "anomalies". In that case, the pigments of high density appear clearer on the shootings. Besides, to reveal some specific details, we also present the X-ray radiography images in their “positive” form: so the denser elements are darker on the shootings. These information are notified case by case. The radiography shootings can present the whole painting after digital reconstruction or detailed areas

Page 6: CIRAM Scientific Study of Paintings - 2013

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Pentiments and surpaints examples

The radiography underlines a pentiment at the level of the hand. Oil painting, private collection.

The X-Ray radiography underlines the presence of a cow, clearly identifiable, behind the vegetal lot and a part of the dirt track. Oil painting, private collection.

Page 7: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

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Scanning electron microscopy (SEM), Raman, PIXE, IRTF... These techniques permit to characterize the chemical composition of the pigments, of the minerals, of the binders and of the painting grounds. Example of SEM study An easel painting pigments analysis is going to permit to determine its chemical nature and to estimate the chronological compatibility between its use and the supposed era of the work of art. The following example concerns a sample of white pictorial layer Views of detail of the sample of white pictorial material. The white colouring is homogeneous. The indented texture of the sample suggests that it’s a painting with an acrylic binder (left: metallographic microscopy, dark area, x200; right : SEM, ES, x450). The elementary analysis of this white pictorial layer (Fig. 10) indicates that it is principally composed of zinc, with traces of silicon and of iron. These two last elements can correspond to an adjoining pictorial layer. The zinc is correlated to the presence of zinc oxide, ZnO, generally designated as pigment of « zinc white ». This pigment was widely diffused from 1850 and it is still used today

EDX spectra of the white pictorial layer. It is principally composed of zinc. This is a pigment of zinc white

Page 8: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

The second example concerns a sample showing a blue coloration with numerous white to grey punctuations (Fig. 11). These punctuations can correspond to a white preparation layer and/or to the mineral associated to the blue pigment.

General view of the sample of blue pictorial material. We observe a blue coloration associated to white to grey punctuations. (Stereomicroscop, x100).

The analysis of the blue pictorial layer (Fig. 12) shows that it is principally composed of silicon, potassium and calcium that correspond to the vitreous matrix. We also detect cobalt, responsible of the blue coloration. The presence of cobalt, of iron, of manganese and of arsenic suggests the use of ores of cobalt (skutterudite, cobaltite…) for the preparation of this "frit" of cobalt. This is a smalt pigment. The lead marks detected at the level of the blue pictorial layer correspond to the use of lead carbonate (white lead or ceruse). This pigment may have been used as mineral and/or as white painting ground. Cobalt is used as blue pigment of the vitreous materials (glaze, enamel, glass) since the ancient Egypt. In European graphic arts its making and use become a standard from the 16th century. View in detail and EDX spectra of the blue pictorial layer. Observation with high magnification of a vitreous phase of smalt (S) associated to microparticuls of white lead (arrows). We detect silicon, potassium, calcium, iron, cobalt, arsenic and manganese. This composition corresponds to the blue pigments of smalt kind. (SEM, ERD, x700).

S

Page 9: CIRAM Scientific Study of Paintings - 2013

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Example of RAMAN study The study by micro-spectrometry Raman is non-destructive; that’s why no sample is necessary. The examples of Raman study shown below reveal the presence of compounds corresponding to sulphate of barium (barytine) (Fig. 13), to white lead or ceruse (Fig. 14) or to black carbon (Fig. 15).

Raman spectra of a pictorial layer (a/) compared to the one of the barytine (b/). One of the compounds of this layer corresponds to sulphate of barium.

Raman spectra of a pictorial layer (a/) compared to the one of white lead (b/). One of the compounds of the layer corresponds to ceruse.

Raman spectra of a pictorial layer (a/) compared to the one of the black carbon (b/). One of the compounds of this layer corresponds to a black pigment made with black carbon or lamp-black.

a/

b/

b/

a/

a/

b/

Page 10: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

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Dendrochronology or Radiocarbon (14C) dating These techniques give chronological information about the support (canvas, wood, paper…) and/or the stretcher, which are complementary of the stylistic analysis of the work of art. Radiocarbon (14C) dating After cleaning of the wood sample and extraction of the CO2, the different carbon isotopes are separated by mass spectrometry. Then, the concentration in 14C is determined by comparing simultaneously the measures of 14C, 13C and 12C with the ones of reference products (oxalic acid, CO2, coal). The conventional age 14C is calculated with the method described by Stuiver and Polach (Radiocarbon 19/3 (1977), 355); it considers the correction of the isotopic fragmentation (δ13C), based on the comparison of the concentration ratio 13C/12C and 14C/12C. The uncertainty of measure (σ) merge the statistical uncertainties of the counting of the 14C residual, the variability of the measures and the effects of the subtraction of the « white ». The calendar age is calculated thanks to the following calibration: “CALIB rev 4.3” (Data set 2, 1998 decadal atmospheric data), Stuiver et al., Radiocarbon 40 (1998), 1041 - 1083. In the example presented below, a sufficient quantity of carbon was extracted of the sample, and a signal of satisfactory intensity was obtained during the measurement by AMS. The value of δ13C is normal. The results are reliable. Fraction pMC corrected Conventional age δ13C(‰) wood, alkaline residue, 4.1 mg C 96.63 ± 0.33 275 ± 30 BP -24.13 ± 0.09 Radiocarbon age: 276 ± 28 years BP Calibrated age: 2 Sigma cal AD 1514 - 1600 (Probability 48,8 %) (Probability 95,4 %) 1616 - 1668 (Probability 42,5 %)

1782 - 1798 (Probability 4,1 %)

In this example, the wood of the support is dated by Radiocarbon14 between the beginning of the 16th century and the second half of the 17th century.

Page 11: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

Few bibliographical references Imaging D. Bagault, D. Vigears, 1995, La photographie au Laboratoire de Recherche des Musées de France, Techne n°2. M. Déribéré, 1976, "La photographie scientifique", In Toute la photographie, pratique, esthétique, applications modernes, publié sous la direction de P. Montel, Ed. Larousse, 3ème édition, Paris. J. Lang, A. Middleton, 2005, Radiography of cultural material, Elsevier, 198 p. H. Verougstraete, R. Van Schoute, T.H. Borchert, 2004, Restaurateurs ou faussaires des Primitifs Flamands, Ludion, 160 p. Pigments analysis D.A. Scott, L.S. Dodd, 2003, An Egyptian cartonnage of the Graeco-Roman period: examination and discoveries, Studies in Conservation, 48, 1, 41-56. D.A. Scott, L.S. Dodd, J. Furikata, S. Taminoto, J. Keeney, M.R. Schilling, E. Cowan, 2004, An ancient cartonnage broad collar: technical examination of pigments and binding media, Studies in Conservation, 49, 3, 177-192. F. Perego, 2005, Dictionnaire des matériaux du peintre, Belin, Paris, 895 p. J. Ambers, 2004, Raman analysis of pigments from the Egyptian Old Kingdom, Journal of Raman Spectroscopy, 35, 8-9, 768-773. J.M. Tullianni, C. Bertolini Cestari, 2005, Study of the degradation causes affecting stucco sculpture from the Valentino castle in Turin, Materials and structure, 38, 425-432. G. Rizzo, L. Ercoli, F. D'Agostino, 2003, The stucco work of Giacomo Serpotta and the Serpotta school. Constitutive materials, degradation and decay, Annali di Chimica, 93, 873-880. I.M. Bell, R.J.H. Clarck, P.J. Gibbs, 1997, Raman spectroscopic library of natural and synthetic pigments (pre-~ 1850 AD), Spectrochimica Acta Part A, 53, 2159-2179. K. Castro, P. Vandenabeele, M.D. Rodriguez-Laso, L. Moens, J.M. Madariaga, 2004, Micro-Raman analysis of coloured lithographs, Analytical and Bioanalytical Chemistry, 379, 674-683. D. Hradil, T. Grygar, J. Hradilova, P. Bezdicka, 2003, Clay and iron oxide pigments in the history of painting, Applied Clay Science, 22, 223-236. R.L. Frost, H.G.M. Edwards, L. Duong, T. Kloprogge and W.N. Martens, 2002, Raman spectroscopy and SEM study of cinnabar from Herod's palace and its likely origin, Analyst, 127, 2, 293-296. W.C. Mc Crone, 1994, Polarized light microscopy in conservation: a personal perspective, Journal of the American Institute for Conservation, 33, 2, 101-114. F. Perego, 2005, Dictionnaire des matériaux du peintre, Belin, Paris, 895 p. B. Mûhlethaler and J. Thissen, 1969, Identification of the materials of paintings, Studies in Conservation, 14, 47-61. Radiocarbon dating 14 G. Marlowe, 1999, « Year one: radiocarbon dating and American archaeology, 1947-1948 », American Antiquity, LXIV/1, p. 9-32. W.F. Libby, 1955, Radiocarbon dating. 2nd ed., University of Chicago Press, Chicago. G. Marlowe, 1980, « W.F Libby and the archaeologists, 1946-1948 », Radiocarbon, XXII/3, p. 1005-1014. R.E. Taylor, 1987, Radiocarbon dating: an archaeological perspective, Academic Press, London, chap. 6. M. Stuiver et al., 1998, « CALIB rev 4.3 (Data set 2) », Radiocarbon, vol. 40, p. 1041-1083. A.J.T. Jull, 2003, Radiocarbon, vol. 46, 18th conference, Wellington.

Page 12: CIRAM Scientific Study of Paintings - 2013

Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 – [email protected] North America - Phone +1 917 509 5616 – [email protected]

© 2013 - www.ciram-art.com

To learn more about CIRAM Services To ask for a Study Visit our website www.ciram-art.com Contact us EUROPE Office & Laboratory, Bordeaux, France

Phone / Fax +33 (0)5 56 23 45 35 e-mail [email protected]

NORTH AMERICA Office, New York, USA

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