The thermoluminescence dating is a reliable scientific method for estimating the period of the final firing of ceramic or terracotta objects.
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Thermoluminescence is based on a physical phenomenon: the crystals (particularly quartz or feldspars) present in ceramics accumulate energy over time from ambient natural radiation. When an object is heated for the last time (during its manufacturing firing), this energy is reset to zero.
When heating a sample in the laboratory, this energy is released in the form of light. Its intensity allows us to estimate the age of the object: the stronger the light, the older the object.
This method applies to cooked materials such as:
In the field of art, dating is not limited to placing an object in time: it constitutes scientific proof of authenticity. Ceramic, terracotta, or porcelain works are particularly exposed to the risks of modern counterfeits, sometimes very elaborate, or of undocumented ancient 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 attest to the period of manufacture of the object.
Thermoluminescence dating precisely addresses this challenge by providing reliable and 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 speak of a test of antiquity: this method allows for an approximate estimation of the period of the object's last firing. In the absence of archaeological context, this is not an absolute dating method, but a reliable indication of its antiquity or modernity.
On the other hand, when an artifact is discovered in archaeological context, CIRAM scientists can achieve more precise dating by measuring the annual irradiation rate from the site.
For ceramic or terracotta art objects, CIRAM thus performs a thermoluminescence dating test, allowing the identification of the period of the material's last firing with a high level of reliability.
Request a studyCIRAM has its own laboratory, entirely dedicated to the dating of ceramic or terracotta objects. Our teams of doctors and engineers apply rigorous protocols, identical to those used in public research laboratories.
We use a latest-generation device: the LexsygSmart TL-OSL, designed to guarantee:
The analysis begins with the collection of a sample, which is then cleaned and treated to isolate the luminescent minerals (quartz, feldspars). The grains are then heated in a TL-OSL reader, under controlled darkness. The emitted light is captured by a photomultiplier, and the intensity of the natural signal is then compared to that obtained after adding doses of artificial irradiation.
Each step follows a rigorous protocol, ensuring traceability, reproducibility and scientific reliability of results.
Thanks to X-rays and 3D scans, it is possible to detect more elaborate fakes.
The coupling of X-ray radiography or 3D scanning with thermoluminescence (TL test) will reveal the internal structure of the object, any restoration areas, and any reassemblies.
Finally, the analysis and interpretation of the results by our doctors and engineers guarantee the reliability of the results.
Specializing in the study of art objects, CIRAMhas been assisting museums, collectors, auction houses, and experts for over 20 years in the dating of ceramic or terracotta pieces. Our state-of-the-art equipment, such as the TL-OSL LexsygSmart reader, and our rigorous protocols ensure precise 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.
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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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