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CIRAM Analysis – Works of art
                                              Analysis, authentication and dating
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Version 1.1 mise à jour le 18 mai 2009                                                                                   S...
Version 1.1 mise à jour le 18 mai 2009                                                          Stones analysis
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Version 1.1 mise à jour le 18 mai 2009                                                             Stones analysis
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Version 1.1 mise à jour le 18 mai 2009                                                                           Stones an...
Version 1.1 mise à jour le 18 mai 2009                                                                          Stones ana...
Version 1.1 mise à jour le 18 mai 2009                                                                        Stones analy...
Version 1.1 mise à jour le 18 mai 2009                                                                    Stones analysis
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Version 1.1 mise à jour le 18 mai 2009                                                                    Stones analysis
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Version 1.1 mise à jour le 18 mai 2009                                                                            Stones a...
Version 1.1 mise à jour le 18 mai 2009                                                             Stones analysis
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Version 1.1 mise à jour le 18 mai 2009                                                                           Stones an...
Version 1.1 mise à jour le 18 mai 2009                                                                 Stones analysis
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Version 1.1 mise à jour le 18 mai 2009                                                                  Stones analysis
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CIRAM Authentication Of Stone Objects - 2013

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A precious document from CIRAM laboratory to discover and understand how it is possible to test stone works of art.

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CIRAM Authentication Of Stone Objects - 2013

  1. 1. CIRAM Analysis – Works of art Analysis, authentication and dating of works of art CIRAM Analysis Analysis and dating of cultural heritage CIRAM Archaeology Analysis and dating of archaeological artefacts CIRAM Track Safe marking and traceability of objects AUTHENTICATION OF STONE SCULPTURES: CONTRIBUTION OF THE SCANNING ELECTRON MICROSCOPY 16, Avenue Pey Berland – Chem’Innov – 33607 Pessac cedex – France Tél. : +33 5 57 34 21 18 Fax : +33 5 56 23 45 35 www.ciram-art.com Contact : Dr Olivier Bobin CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  2. 2. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 2/ 15 The analysis’ steps Dating Formation of the stone and of the crystals (millions, billions of years) : no interest for the authentication. Dating of the sculpture phase: impossible for works of art (no chronological marker) Surface analysis Tools marks: fashioning and polishing, metallic shreds... Superficial deposits: burial sediments, modern application... Surface treatments: cleaning, acid attack… Polychromy: painting ground, pigments, lacquers... Material analysis Stone nature Degree and origin of the weathering Decay gradient Study of the object homogeneity Restoration areas Assembly… CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  3. 3. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 3/ 15 The characteristics of the stone THE MATERIAL It is an heterogeneous material that associates mineral K M phases more or less denses, more or less resistant… Sandstone: sedimentary stone composed by quartz, feldspars, micas aggregated by a clay or calcitic cement. Q N Q Limestone, marble: stones composed by calcite and dolomite. C K Granite, Schist, … Jade, Stone crystal, … C ITS WEATHERING Area weathered In surface Ionic exchanges, dissolution, reprecipitation Embrittlement sheeding, of the surface weathering, erosion CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  4. 4. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 4/ 15 The characteristics of a stone Why does the composition of the stone constitute the first step of the analysis? We investigate the weathering processes of the stone. They directly depend on its nature: ⇒ reprecipitation of iron and/or manganese oxides on the sandstones ⇒ disintegration and dissolution of the calcite in limestones ⇒ … Some modern materials are used to simulate stones. Sorel cement (magnesium oxychlorides) invented in 1867 CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  5. 5. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 5/ 15 The surface analysis THE TOOLS’ SHAPING MARKS traces of shaping of the stone, by bush hammering… decor by incisions … Acier inoxydable (Fe-Cr-Ni) stainless steel ⇒ Recently sculpted ⇒ Recently cleaned up METALLIC SHREDS Ancient alloy: iron, bronze… Modern alloy: Stainless steel, tungsten… Iron ⇒ Formerly sculpted ⇒ Recently sculpted with a metal of quot;ancient typequot; THE TOOLS’ POLISHING MARKS We use an abrasive (hard mineral) of small-size. The result is the presence of polishing scratches. Traditional techniques (manual) leave scratches with variable and Modern techniques (mechanical) multidirectional dimensions. leave fine and unidirectional scratches. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  6. 6. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 6/ 15 The surface analysis THE SUPERFICIAL DEPOSITS They are generally constituted of earth, roots, fungus, … These deposits can come from a natural environment (burial sediments) or from a voluntary application. Iron and Manganese mineral silicated phase : Fungus and/or bacteria colonies: buried in natural deposit or pigment applied ? a humic environment Clinker phase: modern cement Volontary application, to simulate roots’ traces CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  7. 7. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 7/ 15 The surface analysis THE DECORATIONS It is generally about polychromy or lacquer. White lead (ceruse) Pigments and techniques are of ancient type ⇒ Original polychromy ⇒ Modern polychromy realised with pigments of ancient type Pigments and techniques are of modern type Modern application on a modern object White titanium (1923) Lithopone white(1870) Modern application on an ancient object THE SURFACE ANALYSIS, in summary: Preliminary study that permits to turn down the obvious fakes. Complementary to the analysis of a cross-section, to characterize the whole object. Study necessary, but not sufficient to establish the antiquity of an object. Ferric chloride: orange acid used to attack the material and to simulate a burying deposit. Absolutely not, a cleaning product or a natural compound. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  8. 8. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 8/ 15 Stones weathering Which are the characteristics of a weathered stone? Does a weathering gradient between the carved surface and the interior of the material exist? Is the stone decay natural or artificial? The results obtained are going to form a bundle of clues that will permit to give our opinion on their compatibility or not with the presumed age of the object. Typical conclusions These results indicate the object has not suffered any deteriorations linked to a natural long time ageing, posterior to its phase of sculpture. These results are inconsistant with the presumed age of the object. These results indicate that the object has suffered a deterioration linked to a natural long time ageing, posterior to its phase of sculpture. These results are consistant with the presumed age of the object. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  9. 9. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 9/ 15 Stones weathering THE CHARACTERISTICS OF THE WEATHERING –The superficial porosity A superficial porosity, caused by the cement dissolution, is developing. It is a natural phenomenon, nevertheless it is necessary to control there is no acid residue. Deteriorated stone Undeteriorated stone THE CHARACTERISTICS OF THE WEATHERING – The superficial decohesion The grains present in surface break away the ones from the others. This is also caused by the partial dissolution of the cement. It is nevertheless necessary to control the decohesion does not come from the work of manufacturing. Deteriorated stone Undeteriorated stone CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  10. 10. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 10/ 15 Stones weathering THE CHARACTERISTICS OF THE WEATHERING – The differential dissolution The feldspars are more sensible to deterioration than quartz. That’s why we have to observe the preferential dissolution of the feldspars. F Q F F Q Deteriorated stone Undeteriorated stone We also observe the exfoliation of the micas. M Q M Deteriorated stone Undeteriorated stone In calcareous stones, we find this phenomenon of preferential dissolution of calcite than dolomite. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  11. 11. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 11/ 15 Stones weathering THE CHARACTERISTICS OF THE WEATHERING – The desquamation The desquamation surface is the extreme result of the decohesion and of the dissolution. It can be observed as well on sandstones as on limestones. THE CHARACTERISTICS OF THE WEATHERING – The reprecipitation of oxides The dissolution of the intergranular cement and the exchange with the environment involve the formation of oxides and/or of hydroxides of iron and of manganese: quot;black patinaquot; of the sandstones. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  12. 12. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 12/ 15 Stones weathering THE CHARACTERISTICS OF THE WEATHERING – The gradient The carved surface has to show deterioration degree more important than in the middle (cutting line) or than at the level of the breaks. The intern part of the stone and the break areas are better preserved, since they suffer few or no direct quot;attacksquot; from the environment. It results a deterioration gradient between the carved surface, the breaks areas and the interior of the material. Surface sculpted Break Cutting line Stone gradually weathered THE CHARACTERISTICS OF THE WEATHERING, in summary: The superficial porosity The superficial decohesion The differential dissolution The desquamation of the surface The reprecipitation of iron and manganese oxides Presence of a weathering gradient Is it necessary to observe all this criteria to claim a stone is naturally deteriorated? Is it possible to reproduce artificially these processes? CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  13. 13. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 13/ 15 Stones weathering THE ARTIFICIAL WEATHERING The only means to accelerate or simulate a deterioration, is to make a surface treatment, principally with strong acids: hydrochloric, sulphuric, phosphoric, hydrofluoric acid... ⇒ Elements markers of this type of attack Cl, S, P, F ⇒ There is no differential dissolution ⇒ The front attack is linear Fluorine (HF acid) Fluorine (HF acid) Stone artificially deteriorated In summary… The authentication research uses a bundle of clues that permits to define: The nature of the material The degree of the weathering The deterioration gradient The nature of the decay The surface analysis permits to obtain complementary information: The tool marks The superficial deposits The decoration Nevertheless these analysis techniques encounter limits: They are not dating techniques. They study slow processes: efficient for objects of at least 300 years old. The samplings are reduced compared to the dimensions of the object. It would be necessary to define, in complement, the degree of homogeneity and deterioration of the object. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  14. 14. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 14/ 15 The homogeneity degree of the object The X-ray radiography This method allows to evaluate the structural homogeneity of the piece and to locate: ⇒ the restoration areas ⇒ the assembly areas However, the dimensions often important of stone sculptures limit our investigations by X-ray radiography (penetration of the X-rays). No break in the neck Break in the neck Break in the neck and metallic tenon CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com
  15. 15. Version 1.1 mise à jour le 18 mai 2009 Stones analysis Page 15/ 15 In summary… The authentication research involves the complementarity of the approaches and of the analysis methods: Analysis of the constitutive material of the object Analysis of the degree and the nature of the weathering Characterization of the intern structure and of the homogeneity of the object CIRAM proposes a wide range of analysis permiting to bring the informations necessary to a rigorous authentication research. CIRAM SARL au capital de 21.000 € ENSCPB – Chem’Innov Tél. & Fax : 00.33.(0)5.56.23.45.35 480 825 652 RCS Bordeaux - APE 7112B 16 avenue Pey Berland Portable : 00.33.(0)6.66.63.80.99 SIRET 480 825 652 00021 33607 Pessac Cedex E-mail : contact@ciram-art.com N° TVA Intracommunautaire FR 56 480 825 652 France Site web : www.ciram-art.com

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