african masksTL tests thermoluminescence
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A fine Eastern Pende Panya-Gombe African mask. Coll.: David Norden

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CT scans ] Benin Bronzes

ThermoLuminescence Laboratories TL tests

Often people ask me how to be sure about an object age. The experience and to know how old objects looks like, by visiting Museums, international  ASA Alliance Science Art dealers, fairs and auction, helps you to put a reference frame, and the scientific tests will be there to CONFIRM what you already knew, with visual inspection. Don't think a test or a written authenticity certificate is 100% full proof or you might be cheated. Find a complete list of TL laboratories below.

David Norden

Google
 

TL TESTS ON BRONZES OR IVORY ARE VERY CONTROVERSIAL AND SHOULD NOT BE TAKEN 100 % SERIOUSLY !

For me BRONZES CAN'T BE DATED AND CERTAINLY NOT WITH TL TESTS until proven to have internal corrosion and logical traces of aging.

THE ONLY WAY TO TEST BRONZES ARE INTERNAL CORROSION TESTS AND METAL COMPOSITION COMPARED TO THE ONES IN THE BRITISH MUSEUM (For Benin bronzes) THEY ONLY DO THIS IN THE OXFORD LABORATORIES. 

METAL IS WORKING AS A SHIELD THAT STOPS THE NATURAL DECREASE IN RADIOACTIVITY.

So in case someone proposes you a Bronze or metal object with a TL test don't buy it before having done a second test to see if there is some internal corrosion of the metal and/or compare metal composition with known old pieces like the ones in the British Museum

DAVID NORDEN.

Tests can also be fooled. I had a Benin bronzes with a TL test from the inside core, and after doing a test on internal corrosion it proved not to be a valid test.

TL tests on Bronzes are controversial since you need a proof the core is original, and also the metal is  a quite of shield for the inside terracotta.

Also testing the core is not enough as a valid proof of age, since for bronzes you need to know if there is an internal corrosion in the metal, and the metal composition.

Thermoluminescence C14 test can only be used to date Terracotta's older than 300 years. eg.: Nok and Sokoto terracotta's that are 2500 - 1500 years old, and they will determine when it was fired for the last time. I also recommend to only trust European and American laboratories with a good reputation, avoid Chinese or South African tested items, read more about it at  http://seattletimes.nwsource.com/news/local/links/chinese_art/ 

Wood datation is more problematic and can also only be done for pieces older than 300 years old, and in association with a mineralogical test, to see if it is not a recent cut on an old piece of wood.

The best known laboratory in the World is Oxford, but you have plenty of other University's doing tests . 

See the middle of page for private commercial laboratories

David Norden.

read opposite view at Benin creation and read also the opinion of Reginald_Groux_on TL test and the answer of Galerie Hermann who did some testing on Bronzes he bought in Africa and comparisons with Museum pieces:

http://galerie-herrmann.com/arts/art6/Kolumnen/2008_10_TL_vrs_Metalanalyses.htm

You can have your own opinion, but for me these only TL tested bronzes are worthless.

David Norden

fist part found at:  http://www.aber.ac.uk/~qecwww/  

Europe University with TL departments 

University of Wales Aberystwyth  University of Durham luminescence laboratory University of Catania - Gruppo di Archaeometria di Catania
Technische Universitat Bergakademie
Freiberg
and dissertation page
Heidelberg- Max Planck Institute University of Liverpool
Oxford- Research Laboratory for Archaeology and the History of Art Sheffield- Centre for International Drylands Research
Technologiestichting STW
Scottish Universities Research and Reactor Centre (SURRC) Clermont Research Laboratory for Quaternary Geochronology, Tallinn Technical University
Netherlands Centre for Luminescence dating Laboratory  of Archaeometry, National Center for Scientific Research  Demokritos, Greece  

North America

University of Illinois at Chicago Dalhousie- TOSL laboratory AGE Laboratory  
McMaster University, Canada
Montreal- Laboratoire de luminescence Lux, University of Quebec at Montreal  Oklahoma State University  
Reno- Desert Research Institute
Salt Lake City  Simon Fraser University, Canada  University of Washington

Australia & New Zealand 

Australian National University, Canberra  Victoria University, Wellington

 

 

Private TL tests Laboratories

ArcheoLabs TL
méthodes scientifiques de datation appliquées à l'Art 
scientific dating methods applied to Art

une adresse sérieuse en France :Archéolabs dans l'Isère, la plupart des
archéologues travaillent avec eux

Le Châtelard, 38840, Saint Bonnet de Chavagne, France
Tel: +33 (0)4 76 38 51 03. Fax: +33 (0)4 76 64 01 60

Dr. Robert Neunteufel
Antiques Analytics GmbH
D-65813 Eppstein
Telefon +49(0)6198-576070

Mobil +49(0)151-55105713
Telefax +49(0)6198-500534
E-Mail:info@a-analytics.de
Internet: www.a-analytics.de 

Bortolot Daybreak Corporation
50 Denison Drive
Guilford, CT 06437-2344
U.S.A.

Physical address (no mail or deliveries, please!): Bortolot Daybreak Corporation
11 Sycamore Way Unit 110 (Gray Eagle Business Park)
Branford CT 06405
U.S.A.

Telephone:    +1 203 453 3299 / +1 203 488 2483 Fax:   +1 203 458 9395

E-mail:  Customer support:  bortolotdaybreak @ sbcglobal.net
              (please remove the spaces either side of the '@' for a valid e-mail address)

Labor Ralf Kotalla 

http://www.kotalla.de/englisch/indexhaupt_e.htm  Kätzling 2, D-72401 Haigerloch ­ Weildorf  Tel.: 0049­7474/9536-0, Fax: 0049­7474/9536-10

Certificate kotallaTo satisfy the passion of collectors the inventive genius of falsifiers seems to be nearly inexhaustible. Proceeding on the assumption that nowadays it is possible to find everything ­ from total falsifications up to malicious part restorations on the international market of art, the question arises how the collector protects himself from falsifications and financial losses. 
A lot of minerals have the feature to store energy from a field of radioactive radiation and to radiate it again in form of light impulses, the so­called thermoluminescence "TL". The field is formed by the tracks of non­stable uranium, thorium, potassium and rubidium isotopes, which are nearly everywhere in the earth´s crust. With some exceptions, each clay, which is used for forming objets d´art and articles of daily use, contains such radiosensitive minerals. Quartz and feldspar have a favourite position as supporter of the "TL" feature.
The thermoluminescence analysis gives information of the last time of burning. The determination of age in the "TL" certificate refers to the "burning age" of the sample, which means the time of its last heating to a temperature of more than 500° celsius and shows the place where the sample has been taken.
To determinate the age, the ceramic samples are heated under conditions of laboratory, through which energy is setting free in form of visible light impulses. This energy is the measure for the radioactive self­ and ambient radiation, which influenced the ceramic minerals since the last burning. The more of the self­ and ambient radiation has been stored, the older the ceramics has to be classified.

As therefore the age of ceramics depends on the measure of the free setting energy, an exact determination of age is possible. 

The Ralf Kotalla Laboratory establishes only top quality expert reports. These are outstanding by quickness of analysis, precision of statements and layout. In urgent cases, transportation of objects for analysis or the taking of samples on the spot, abroad or at home, are part of the institute´s extensive service. Regular visits to Paris, Brussels and Zurich round off our service.
In all cases, from the taking of samples to the complete expert´s report, Ralf Kotalla is your partner.

 http://www.kotalla.de/englisch/indexhaupt_e.htm  Kätzling 2, D-72401 Haigerloch ­ Weildorf  Tel.: 0049­7474/9536-0, Fax: 0049­7474/9536-10

Marc GHYSELS

If you need to see the inside of the object, you need a CT-scans:

Click to see the inside Ct scanDr Marc GHYSELS Radiologist Artefact investigation by X-ray and CT Scanner

81 Rue Franz Merjay B 1050 Brussels - Belgium 

Phone : +32 2 343 53 93 Fax : +32 2 343 09 93 Mobile : +32 495 540 548
Email : marc.ghysels*skynet.be

see the inside at the website: http://www.marc-ghysels.com/ 

Same service is provided in the US by CT scans Rare Collections

Patrick Laycock in Bruxelles.

Brussels Art Laboratory.  141, avenue Winston Churchill      1180 Brussels Belgium Tel. : 00-322-344.54.70 Fax : 00-322-346.14.94 

The customers of Leacock's  Brussels Art Laboratory include private collectors, antique dealers, antique fairs (cf. vetting committee), auction-rooms, museums and the Belgian customs, courts and criminal investigation department

Monday and Wednesday : 9 to 12 a.m. and 2 to 6 p.m Saturday morning : 9 to 12 a.m.

Also :

Museo del Collezionista d'Arte, Milano, Italy

If you need to date wooden pieces 50 years or older there is a laboratory in Milan that is quite interesting. They developed a method to date wood that is different from C14 (valid on wooden pieces older than 300 years only) , they claim that they can date younger pieces quite accurately. 

They don't take the samples themselves, so the result is valid only for yourself as a confirmation (or infirmation) from what you know, and not a selling argument.

Also the analyses are only to know the age of the wood, and not the age of the carving, and also it is not because a piece is old that it gives a guarantee that the piece was made in a tribal context, stylistic studies and comparisons with known pieces are other keys to consider when establishing a piece authenticity.

www.MuseoArteScienza.com

via Q. Sella,4 -20121 Milano-  Piazza Castello Tel:+390272022488. Fax:+390272023156.  

e-mail: info (at) museoartescienza.com

Ciram Laboratoire Analyse Marquage

9 chemin du Batan 

F33760 Cessac France

Tel/Fax 00 33 (0)5 56 23 45 35

contact*ciram-art.com

 http://www.ciram-art.com/ CIRAM, laboratoire d'analyse scientifique
d'objets d'art et du patrimoine. Analyses des matériaux, Authentification et datation

CT scans Rare Collections  (click on link to read more)

5865 Neal Avenue North, Suite 345
Stillwater, MN 55082 USA 

Tel 612-961-4747    mark@rare-collections.com

ASA Alliance Science ArtA S A Francine Maurer 

We just heard about the tragic death of Francine Maurer and her husband (May 2006). We will miss them

Dear Mr. Norden,

on your home page, you have announced the death of Mrs Maurer and her husband, which is unfortunately right. 

They both died in May last year but the dating laboratory called "ASA Labor für Archaeometrie GmbH" still exists. 

We, the team of Mrs Maurer, have run the lab since then and we still carry out authenticity tests for our customers in our lab in Wadgassen (TL-dating, OSL-dating and C14 radiocarbon dating). Our contact in Paris is still available, too (mobile phone +33 (0)6 08 64 84 22).
Actually, we are updating our homepage and the new version will be hopefully be online within the next few weeks.

May we please ask you to add a comment on your page to explain, that the ASA Labor still exists? The readers of your page might otherwise conclude, that the lab has closed after the death of Mrs Maurer.

If you need any further information or confirmation, please contact us.

Thank you very much in advance and kind regards

The ASA team  www.asa-art.de  

Dr. Anja M. Zander ASA
Labor für Archaeometrie GmbH
Ludweilerstr. 135
D66787 Wadgassen-Werbeln

Tel.: +49 (0)6834/6239
Fax.: +49 (0)6834/61680
Zander @asa-art.de

Our new official email-address:
ASA.Labor @asa-art.de  

 

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The Tribal Arts of Africa

The Tribal Arts of Africa
Author: Jean-Baptiste Bacquart

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