Direct dating archeology
Better still, unlike radiocarbon dating, the effect luminescence dating measures increases with time.As a result, there is no upper date limit set by the sensitivity of the method itself, although other factors may limit the method's feasibility.
The way you measure energy stored in an object that you expect has been exposed to heat or light in the past is to stimulate that object again and measure the amount of energy released.
TL dating is a matter of comparing the energy stored in a crystal to what "ought" to be there, thereby coming up with a date-of-last-heated.
In the same way, more or less, OSL (optically stimulated luminescence) dating measures the last time an object was exposed to sunlight.
During the 1960s and 70s, the Oxford University Research Laboratory for Archaeology and History of Art led in the development of TL as a method of dating archaeological materials.
, Professor David Pearce, Director of the Rock Art Research Institute at the University of the Witwatersrand, Johannesburg, Adelphine Bonneau of Laval University, and colleagues at the University of Oxford showed that paintings in south-eastern Botswana are at least 5,500 years old, whilst paintings in Lesotho and the Eastern Cape Drakensberg, South Africa, date as far back as 3,000 years.