When the object is heated to 350 degrees Celsius the trapped electrons are released and this is called a clock resetting event.
From this time on, electrons start to build up again because of the natural radioactivity.
The TL operator generally takes samples for dating from the bottom, avoiding damage to the image of the artwork.
TL is based on the fact that almost all natural minerals are thermoluminescent.
When collecting samples for thermoluminescence dating, several samples from different vessels should be taken, not smaller than 1 gram.
Samples should not be exposed to heat and powdery examples should not be exposed to bright light.
For instance, it is possible to date the wood support of a panel as well as canvas.
The three most important dating techniques which are useful for the analysis of works of art are: Thermoluminescence (TL), Dendrochronology (DC), and Carbon 14 (C15). It dates items between the years 300-10,000 BP (before present).Measuring the intensity of the luminescence can determine how much time has passed since the last time the object was heated.The light is proportional to the amount of radiation absorbed since the material was last heated.Natural radioactivity causes latent thermoluminescence to build up so the older an object is, the more light is produced.Therefore, thermoluminescence dating is actually determining the last time a crystal was heated and electrons were released.Thermoluminescent Natural radioactivity causes the number of trapped electrons to build up.