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

1. Works of Art
AUTHENTICATION
EXPERTISE
DATING
March 2012

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, Christie's, Koller, Piasa, Pierre Bergé & Associés,
Sotheby's, 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. 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 stone
figures 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 can
discuss about their chronological compatibility with the presumed period of the carving of the object.
1st step: Surface analysis – Non intrusive
This 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) M
Modern 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. 2
nd
step: Material and its corrosion - Intrusive C
(5 x 5 mm)
According to the nature of the stone, the corrosion processes
expand differently, but we have to observe a weathering gradient
between 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 strong
acids (hydrochloric, sulfuric, phosphoric, hydrofluoric ...).
They leave detectable elements (Cl, S, P, F) and a
homogeneous 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. Study of metal alloys
Bronze, brass, iron
For copper alloys (bronze and brass), we look for long time processes. So, in the most cases, we only
analyze 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 can
be 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 of
the alloy and the nature of the embedded inclusions.
We can detect formal elements of modernity, as aluminium
or phosphorus.
We can exhibit the incompatibility of the composition of the
alloy with the presumed date of the object (zinc-aluminium-
Aluminium indicates this brass
copper-lead alloy, for example).
has been made after 1850 AD.
Even if the composition is not inconsistent with the
presumed date of the object, it cannot be considered as a
fundamental 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. 2nd step: Corrosion study - Intrusive
(2 x 2 mm)
We have to observe if the corrosion expands deep inside the
alloy (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. Terracotta analysis
Thermoluminescence (TL) Tests
Since 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 deviation
typically around ± 20%.
Nowadays, in order to detect more sophisticated forgeries, it is often necessary to complete the
thermoluminescence approach with the visualisation of the internal structure of the object, with X-ray
radiography or scanner.
Crossing these two scientific techniques, in association with a stylistic analysis, guarantees the
authenticity 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 dose
For 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
50 100 150 200 250 300 350 400 450
recent 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. 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. Study of wood, ivory, bone, textile...
Radiocarbon (C14) dating
Scientific analysis of objects made of wood, ivory, bone and textile (canvas for example) is based on
the 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 the
object and identify forgeries and restoration areas.
An X-ray exploration of the objects can give further information about the shaping of the pieces and their
structural 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 the
measurement of the amount of the 14C that
contain all the organic materials (wood,
plants, bone, ivory…).
Radiocarbon age [BP]
It permits to determine the time since the
death 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. 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 of
calibrated dates for one radiocarbon age.
Radiocarbon age [BP]
Nevertheless, we can promote one or two
of them regarding the percent of probability
that 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 intrusive
The X-Ray exploration allows
observing the structural homogeneity
of 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. To learn more about CIRAM services
To ask for a study …
Visit our website
www.ciram-art.com
Contact us
EUROPE office & laboratory near Bordeaux, France
Tel. / Fax +33 (0)5 56 23 45 35
e-mail contact@ciram-art.com
NORTH AMERICA office in New York, USA
Tel. +1 917 509 5616
e-mail info@ciram-art.com
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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