Sometimes called ‘tree-ring dating’, dendrochronology is the analysis of patterns in tree growth rings to derive information about when the timber originated, such as climate patterns, chronological date, and geographical source. For example, dendrochronology is used on panels made from oak, but it is an enormously powerful tool for establishing the date of creation of many wooden objects.
Radiocarbon, Carbon-14 or 14C dating, or “C14” for short, uses the amount of Carbon-14 isotope in organic material as a marker for dating by comparing it with historical environmental data. Used in fields as diverse as archeology and climate science this is a valuable tool for those of us looking to identify when a work of art was created. Wood, canvas, paper – even the oil in an oil painting – can be dated in this manner.
In the 1950s and 60s, atmospheric nuclear weapons testing resulted in a sharp increase in atmospheric C14 levels. Radiation levels peaked in 1963-4, when concentrations in the northern hemisphere reached nearly twice that of pre-atomic levels. Since a nuclear test ban treaty came into effect in 1963, radiocarbon levels have been decreasing rapidly so that by 2004 they had declined to about 10% above that of the pre-bomb level. The shape and intensity of this ‘bomb-pulse’ is well documented, providing the ability to date organic materials originating since the later 1950s to the present day with a resolution of just a few years. ArtDiscovery has used this technique to successfully date canvas, wooden supports, paper and natural paint media.