What is the radiocarbon dating process?
The radiocarbon dating process measures the levels of the radioactive isotope of carbon, called carbon-14, in an object. The result is compared against a graph of the known levels of carbon-14 in the atmosphere, up to 10,000 years ago to give us a date result. Tree-ring data (dendrochronology) gives us year-by-year known information on the levels of carbon-14 in the atmosphere over time. The date result from comparison with the graph tells us the time period for the death of the living thing that the object is made from. In the case of the Birmingham Qur’an the result 568-645 gives us the 77-year date range of the death of the goat or sheep whose skin made the parchment used in the manuscript.
Radiocarbon dating is the most accurate scientific method available to date early manuscripts. It gives us valuable scientific information on the date the materials used in manuscript construction. This information is combined with palaeographic analysis to help narrow down the date of production of undated manuscripts. In the case of the Birmingham Qur’an, the result of 568-645 has 95.4% probability. This is a transparent result and we put no interpretation on this. For the purpose of the catalogue we endeavour to narrow down the time period by combining the radiocarbon result with the palaeographical and codicological interpretation and understanding of early Arabic Islamic tradition, which gives us a description of the manuscript as ‘mid-seventh century’ for the catalogue.
Radiocarbon dating is a destructive form of testing. This means that a very small piece of material must be removed from the manuscript for testing and cannot be returned. Conservators work to a code of ethics set by the European Confederation of Conservators and Restorers Organisations (ECCO) and the removal of any part of a manuscript would contravene those ethics if it was not for a very strong reason, where the loss to the manuscript is outweighed by the gain from the information from the testing.