Works of Art  AUTHENTICATION       EXPERTISE          DATING             March 2012
When Science meets Arts               Study of Authenticity on                             Dating with C14 and TL         ...
Stone study                                                         sandstone, limestone, schist, jade, marble, ...Dating ...
2                     nd                          step: Material and its corrosion - Intrusive                            ...
Study of metal alloys                                                                                             Bronze, ...
2nd step: Corrosion study - Intrusive                                                      (2 x 2 mm)We have to observe if...
Terracotta analysis                                                                                                       ...
2nd step: Object homogeneity – Non intrusive                          X-Ray radiography of this figure shows no internal a...
Study of wood, ivory, bone, textile...                                                                                    ...
Calibrated date                                                                                                           ...
To learn more about CIRAM servicesTo ask for a study …Visit our websitewww.ciram-art.comContact usEUROPE                  ...
CIRAM -  Scientific Tests on Works of Art - 2013
CIRAM -  Scientific Tests on Works of Art - 2013
CIRAM -  Scientific Tests on Works of Art - 2013
CIRAM -  Scientific Tests on Works of Art - 2013
CIRAM -  Scientific Tests on Works of Art - 2013
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CIRAM - Scientific Tests on Works of Art - 2013

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Leaflet introducing CIRAM laboratory. CIRAM provides scientific services to authenticate the works of art, including radiocarbon & thermoluminescence dating, tests on stone & metal objects.
Worlwide activities.
Offices in France & USA

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CIRAM - Scientific Tests on Works of Art - 2013

  1. 1. Works of Art AUTHENTICATION EXPERTISE DATING March 2012
  2. 2. When Science meets Arts Study of Authenticity on Dating with C14 and TL stone, bronze, brass, silver, tests on wood, ivory, gold, glass, painting… textiles, terracotta…For more than 10 years, CIRAM scientific team has been analyzing more than 5.000 objects for the most renowned dealers, the most prestigious auction houses and major national museums. Extract of the commercial references of CIRAM Art Dealers: Jacques Barrère, Brimo de Laroussilhe, Pierre Dartevelle, Bernard De Grunne, Christian Deydier, Bernard Dulon, Lance Entwistle, Sam Fogg, Fortuna, Michael C. Hughes, Guy Ladrière, J.J Lally & Co, Nasser & Co, Phoenix Ancient Art, Royal Athena, Simon Ray, Jules Speelman Auction houses: Artcurial, Christies, Koller, Piasa, Pierre Bergé & Associés, Sothebys, Tajan Museums: Louvre, Petit Palais, Auguste Rodin, Arthur Rimbaud, Fondation Giacometti, The American Battle Monuments Commission More than a simple provider, CIRAM promises to be a scientific quality partner and an experienced adviser. Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  3. 3. Stone study sandstone, limestone, schist, jade, marble, ...Dating a stone is possible, but it concerns the creation of the material, and not the carved phase.So, we have to analyze the corrosion processes of the stone. As they are very slow, the study of stonefigures is efficient for objects presumed of at least 300 years old.As a consequence, our analysis require complementary approaches (tools marks, surface deposits,weathering of stone, origin of this corrosion…) that form a body of evidences, from which we candiscuss about their chronological compatibility with the presumed period of the carving of the object. 1st step: Surface analysis – Non intrusiveThis preliminary study allows to exhibit modern treatments or not,but it is not sufficient to establish the antiquity of an object.We can investigate for: Traces of carving and polishing, tools chips ... Superficial deposits: burial sediments, modern application ... Surface treatments: cleaning, acid attack ... Ancient and modern polychromy Modern polishing marks (arrows) M lithopone white (1870 AD) MModern polychromy on a modern Manganese-rich deposits (M)object or an ancient one voluntary applied Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  4. 4. 2 nd step: Material and its corrosion - Intrusive C (5 x 5 mm)According to the nature of the stone, the corrosion processesexpand differently, but we have to observe a weathering gradientbetween the carved face and the inside part of the stone.The natural corrosion of a stone presents different features: Surface porosity Important decohesion of grains Grains decohesion (arrows) at the carved surface (C) Differential dissolution Desquamation of the surface Reprecipitation of iron and manganese oxides Gradient of weathering B Decohesion of grains (arrows) at a broken area (B). Medium level.An artificial corrosion of the stone can be made with strongacids (hydrochloric, sulfuric, phosphoric, hydrofluoric ...).They leave detectable elements (Cl, S, P, F) and ahomogeneous weathering frontline. Fluorine-rich layer No decohesion or other corrosion feature inside the stone The expand of corrosion (arrows) Study of stone: from 1100€ is sub-parallel to the surface Scan or X-Ray imaging: from 750€ Study of stone & Scan: 100€ discount Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  5. 5. Study of metal alloys Bronze, brass, ironFor copper alloys (bronze and brass), we look for long time processes. So, in the most cases, we onlyanalyze objects presumed of at least 300 years old.The composition of the alloy, the nature and the degree of the corrosion establish a body of evidences,which indicates if these results are consistent or not with the presumed period of the object.If the piece has a closed shape and contains a residual casting core, a thermoluminescence test canbe performed as a complementary approach with the metal analyses. 1st step: Alloy composition - Intrusive (< 1mm)The first step of the analysis is to define the composition ofthe alloy and the nature of the embedded inclusions.We can detect formal elements of modernity, as aluminiumor phosphorus.We can exhibit the incompatibility of the composition of thealloy with the presumed date of the object (zinc-aluminium- Aluminium indicates this brasscopper-lead alloy, for example). has been made after 1850 AD.Even if the composition is not inconsistent with thepresumed date of the object, it cannot be considered as afundamental proof of authenticity. Zinc-aluminium alloys do not correspond to antique techniques. Is this "classical" bronze ancient or modern? Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  6. 6. 2nd step: Corrosion study - Intrusive (2 x 2 mm)We have to observe if the corrosion expands deep inside thealloy (natural origin) or if it remains superficial (artificial origin).We also have to define its physic-chemical features: Inter-granular corrosion Corrosion processes (arrows) Trans-granular corrosion expand inside the alloy. Weathering of lead globules and their shift to the surface Superficial increase of tin associated with the preferential corrosion of copper-rich phase Dezincification for brass Composition of corrosion products (the "patina") and research of chemical attack evidences (chlorine, sulfur). Typical dendritic corrosion (arrows). Corrosion processes (arrows) are superficial. They result from an acid attack. 3rd step: Object homogeneity – Non intrusive M The X-Ray investigation of the object allows to observe the structural homogeneity of the object and to identify:  restoration areas,  assemblies of ancient (A) and modern (M) alloys A Study of metal: from 1100€ Scan or X-Ray imaging: from 750€ Study of metal & Scan: 100€ discount Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  7. 7. Terracotta analysis Thermoluminescence (TL) TestsSince more than 30 years, the authentication of terracotta is based on thermoluminescence (TL)analysis, which gives an estimated age of the last heating of the material, with a standard deviationtypically around ± 20%.Nowadays, in order to detect more sophisticated forgeries, it is often necessary to complete thethermoluminescence approach with the visualisation of the internal structure of the object, with X-rayradiography or scanner.Crossing these two scientific techniques, in association with a stylistic analysis, guarantees theauthenticity of a terracotta object. 1st step: Thermoluminescence test - Intrusive ( 2 mm drilling) Sample n° 0411-OA-14M-1-P1 Thermoluminescence curves 4000 TL Intensity (a.u.) 3500 3000 Nat 2500 Nat + 4,4 Gy Nat + 8,8 Gy 2000 Background 1500 Sample n° 0411-OA-14M-1-P1 TL as a function of irradiation doseFor a recently heated object, TL 1000 TL intensities between 290 -370 °C ED value (Gy)curves (red) exhibit low intensities. 500 3000 TL Intensity (a.u.)Then, antiquity evaluation gives a 0 2500 50 100 150 200 250 300 350 400 450recent age. Temperature (°C) 2000 1500 1000 500 Dose (Gy) -0,6 Sample n° 0411-OA-14M-1-P2 0 Thermoluminescence curves -2 0 2 4 6 8 10 4500 ED TL Intensity (a.u.) value 4000 3500 Nat 3000 Nat + 4,4 Gy 2500 Nat + 8,8 Gy Background Sample n° 0411-OA-14M-1-P2 2000 TL as a function of irradiation dose 1500 TL intensities between 290 -370 °C ED value (Gy) 3500 1000 TL Intensity (a.u.) 500 3000 0 50 100 150 200 250 2500 300 350 400 450 Temperature (°C) 2000 1500 TL curves and antiquity evaluation 1000 obtained on this sample show that it 500 was anciently heated. Dose (Gy) -5,1 0 -8 -6 -4 -2 0 2 4 6 8 10 The estimated age should be about ED value 1000 ± 150 years old. Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  8. 8. 2nd step: Object homogeneity – Non intrusive X-Ray radiography of this figure shows no internal anomalies. Associated with TL results, it allows confirming its antiquity. X-Ray imaging of this horse shows it is composed by numerous terracotta pieces assembled with a modern technique. Even if TL showed the antiquity of the material, the observation of its structure indicates that this horse is modern. If the thermoluminescence analyses reveal a recent material, then the object is probably a forgery. If the results indicate it is an ancient material, we suggest completing the analysis with X-Ray radiography or scanner, in order to evaluate the homogeneity of the object. Thermoluminescence (TL): 300€ Scan or X-Ray imaging: from 750€ TL & Scan: 100€ discount Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  9. 9. Study of wood, ivory, bone, textile... Radiocarbon (C14) datingScientific analysis of objects made of wood, ivory, bone and textile (canvas for example) is based onthe dating of the raw constitutive material of the pieces, using Carbon 14 method.The age obtained gives information about the death of the organism.Assuming that the C14 measurement does not concern the shaping itself, we can, nevertheless,determine if the antiquity of the material (its date) is consistent or not with the presumed period of theobject and identify forgeries and restoration areas.An X-ray exploration of the objects can give further information about the shaping of the pieces and theirstructural homogeneity. 1st step: Dating of the raw material – Invasive (50 to 200 mg) Calibrated date 1170 – 1264 AD (95.4 %)Carbon 14 dating is based on themeasurement of the amount of the 14C thatcontain all the organic materials (wood,plants, bone, ivory…). Radiocarbon age [BP]It permits to determine the time since thedeath of the organism (cut of the tree,cotton picking, death of the animal…). Calendar date [AD]Radiocarbon age [BP] The accuracy of the dating depends on the antiquity of the material. It can vary between 100 years for material older than 300 years, and 250-300 years for younger ones (from 17th to 1950 AD), because of the necessary calibration of the C14 ages. Calendar date [AD] Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  10. 10. Calibrated date 1669 – 1710 AD (15.9%) 1716 – 1780 AD (26.7%) 1797 – 1890 AD (36.7%)In the range 1650 AD – 1950 AD, 1909 – 1944 AD (16.1%)there are have several possible intervals ofcalibrated dates for one radiocarbon age. Radiocarbon age [BP]Nevertheless, we can promote one or twoof them regarding the percent of probabilitythat affects each interval. Calibrated date 1962 – 1963 AD ( 6.0%) 1976 – 1977 AD (89.4%) Calendar date [AD]C 14 measurement [F C14] For material younger than 1950 AD, we can obtain a very accurate date (less than 10 years), considering the effects of the atmospheric nuclear bomb tests. Calendar date [AD] 2nd step: Object homogeneity – Non intrusiveThe X-Ray exploration allowsobserving the structural homogeneityof the object and identifying: R restoration areas (R) A assemblies of ancient (A) and modern (M) materials M Carbon14 (C14): 1190€, 4 weeks delivery Scan or X-Ray imaging: from 750€ C14 & Scan: 100€ discount Europe - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com
  11. 11. To learn more about CIRAM servicesTo ask for a study …Visit our websitewww.ciram-art.comContact usEUROPE office & laboratory near Bordeaux, France Tel. / Fax +33 (0)5 56 23 45 35 e-mail contact@ciram-art.comNORTH AMERICA office in New York, USA Tel. +1 917 509 5616 e-mail info@ciram-art.comJoin usFacebook, Linkedln, Twitter, Issuu, Slideshare, PearltreesEurope - Phone +33 5 56 23 45 35 – Mobile +33 6 64 14 24 10 - contact@ciram-art.com North America – Mobile +1 917 509 5616 - info@ciram-art.com © 2012 - www.ciram-art.com

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