Pottery dating method
WARNING ABOUT FAKES USING ANCIENT MATERIALS Recently there has been a spate of forgeries devised expressly to attempt circumventing TL dating.These use pottery of the appropriate period to construct objects.This is adequate for the purposes of authentication where the question is whether the piece was fired in antiquity or recently; it will not differentiate, say, between a classic Greek terra cotta and a Roman copy.In some categories of objects, from China, for example, the actual age is quite precisely known for short-lived styles, and it is possible to work "backwards" to get information about the environment in many parts of the world, and some other parameters not usually measurable for art objects.
When dates of a number of sherds associated together are averaged, the error is reduced typically to 7-10 per cent. The succeeding 30 years, and increased understanding of the dosimetry, have not brought much improvement.Using this information often reduces the uncertainty to 15-25 per cent. Nearly any mineral material which has been heated above 500C at a time one wishes to know is a candidate for TL dating. Porcelains, being nearly vitrified, are a special case requiring a fairly large solid core sample, and TL dating of intact objects is not recommended because of the damage caused by sampling.Most porcelain dating is done for insurance purposes on broken objects.Much stoneware is not so hard as porcelain and may be sampled by drilling.The clay cores from lost wax metal castings may readily be tested.