Thermoluminesence Testing

Thermoluminescence (TL) testing can be used to date heat-altered inorganic materials, and is commonly used to date objects as young as 50 years and as old as 35,000 years. In the study of art and artifacts, the primary material tested is fired pottery.

Why And When To Use Thermoluminesence Dating

Optical microscopy study of exterior surfaces can find evidence of alteration, such as over-painting and modern tool marks, as well as evidence of antiquity, such as fossilized organic matter. It is often one of the first examinations performed on an object, and is commonly used to determine the necessity and order of further examination. The non-invasive technique is frequently performed in conjunction with a microscopic examination of the internal structure of a removed sample.


  1. It can be used on a broad range of pottery types, and even on certain metal.

  2. The database for comparison is extensive.

  3. It provides hard scientific evidence of age.

  4. The margin of error on most pottery is reasonably small.

  5. It can detect artificially irradiated pottery from naturally irradiated pottery.

  6. The sample size is relatively small.


  1. Not all pottery is suited to TL testing, most notably porcelains. It is moderately expensive, particularly when expedited services are requested or international shipping is involved.

  2. It is a destructive test, requiring removal of a sample which is destroyed in testing.

  3. Removal of samples requires special training, materials, and conditions.

  4. The time required to obtain results can be significant.

  5. The current sampling/submission protocols and the “results” documents provide no assurance as to whether or not the sample or document is absolutely from or for the examined artifact. These problems can occur through either error or intention.