Thermoluminescence dating is a reliable scientific method for estimating the time of the last firing of ceramic or terracotta objects.
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Thermoluminescence is based on a physical phenomenon: the crystals (notably quartz or feldspar) present in ceramics accumulate energy from the surrounding natural radiation over time. When an object is fired for the last time (manufacturing firing), this energy is reset to zero.
By heating a sample in the laboratory, this energy is released in the form of light. Its intensity is used to estimate the age of the object : the stronger the light, the older the object.
This method applies to baked materials such as :
In the artIn the field of art, dating does more than simply situate an object in time: it constitutes scientific proof of authenticity. Ceramic, terracotta and porcelain works are particularly exposed to the risk of modern forgeries, sometimes very elaborate, or undocumented old restorations that can distort their interpretation.
For professionals in the sector - museums, private collectors, experts, curators or auction houses - it is therefore imperative to be able to rely on a rigorous and recognized method to certify the period of manufacture of an object.
The thermoluminescence dating is precisely the answer to this challenge, providing a reliable, objective analysis.
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It is important to distinguish between two types of thermoluminescence (TL) analysis. In the context of the art market, we refer to this as an age test: this method enables us to roughly estimate the period of the object's last firing. In the absence of an archaeological context, this is not an absolute dating, but a reliable indication of its age or modernity.
On the other hand, when an artifact is discovered in an archaeological contextCIRAM scientists can carry out a more precise dating by measuring the site's annual irradiation rate.
For ceramic and terracotta objets d'art, CIRAM carries out an age test using thermoluminescence, enabling the period of the material's last firing to be identified with a high degree of reliability.
Request a studyCIRAM has its own laboratory, entirely dedicated to the dating of ceramic and terracotta objects. Our teams of doctors and engineers apply rigorous protocols identical to those used in public research laboratories.
We use a state-of-the-art device: the LexsygSmart TL-OSL, designed to guarantee :
Analysis begins with the collection of a sample, which is then cleaned and treated to isolate luminescent minerals (quartz, feldspars). The grains are then heated in a TL-OSL reader, under controlled darkness. The light emitted is captured by a photomultiplier, then the intensity of the natural signal is compared with that obtained after adding doses of artificial irradiation.
Each step follows a rigorous protocol, ensuring traceability, reproducibility and scientific reliability of results.
More sophisticated fakes can be detected usingX-ray and 3D scanners.
Coupling X-ray radiography or 3D scanning with thermoluminescence (TL test) will reveal the object's internal structure, any areas of restoration and any reassembly.
Finally, the analysis and interpretation of the results by our doctors and engineers guarantee the reliability of the results.
Specialized in the study of objets d'art, CIRAM has been helping museums, collectors, auction houses and experts to date ceramic and terracotta pieces for over 20 years. Our state-of-the-art equipment, such as the TL-OSL LexsygSmart reader, and our rigorous protocols ensure accurate results, interpreted by doctors of science. Each analysis is the subject of a complete, clear and usable report.
Reactive and available, our teams guarantee you personalized support to secure your appraisals, acquisitions and sales.
Trust our experts to support you in your analysis projects.
Contact our teamsThe method applies to all fired minerals: terracotta, earthenware, porcelain, tiles, statuettes, sculptures, fragments and ethnographic ceramics.
In the context of the art market, this is an age test: the method provides a reliable estimate of the firing period, with a margin of error of around ±20%. In an archaeological context, precision can be refined by measuring the annual irradiation rate.
The average turnaround time is 2 to 3 weeks, depending on the complexity of the object, the waiting line and any additional analyses required (3D scanner, X-ray, etc.).
Rates depend on the type of object, the complexity of the analysis and the additional services required. For a precise quotation, please contact our teams.
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