CIRAM laboratories offer carbon-14 dating for your works of art, whether made of wood, ivory, bone, wood, plant fibers... or organic matter in general.
How does 14-dating work on wood carvings?
In the late 1940s, American researchers discovered how to use the properties of natural carbon-14 radioactivity to date organic matter. Carbon-14 dating was then exploited by Williard Frank Libby in the 50s on Egyptian samples.
Radiocarbon (carbon 14) dating is used to determine the time elapsed since the death of an organism. This method has revolutionized archaeology, making it possible to date artifacts made of wood, bone, teeth, textiles or even plant macroremains, up to 60,000 years ago.
How does radiocarbon dating work?
This laboratory technique is based on measuring the quantity of carbon 14 remaining in an organism. C14 is a radioactive isotope of carbon that will progressively decrease as soon as the organism dies, according to a known exponential law. It is estimated that the quantity of carbon 14 is halved every 5730 years. However, beyond 60,000 years, the quantity of carbon 14 will be too low to provide a date.
To measure radiocarbon, our scientists use cutting-edge technologies such as particle gas pedal mass spectrometry (AMS). This method is a revolution in the world of dating, since it requires very little material (1 mg of carbon compared with 1g previously), a minimum of time (around 1 hour of counting instead of several days or weeks in the past) and a more precise result.
Calibrating results
To obtain reliable and relevant data, it is important to calibrate the results based on :
- Gross age: expressed in BP years, "before present", based on the assumption that carbon-14 concentration has been constant in time and space.
- To obtain calibrated dates. We know that carbon-14 content has varied as a function of solar activity, climate and industrial activity. This is why we need to correct and calibrate the raw ages using calibration curves. These calibrated dates, combined with probability percentages, are used to verify the authenticity of a wooden sculpture.
Why were the results different before and after 1954?
It is possible to tell whether objects were made before or after 1954 by their carbon-14 content, but how?
This artificial "boundary" was man-made, as atomic bombs and atmospheric nuclear testing in the 50s and 60s doubled the amount of carbon-14 in the atmosphere.
In recent objects, our scientists have detected abnormally high levels of carbon 14. However, since the end of atmospheric nuclear testing in the mid-1960s, we have seen a steady decline in the quantity of C14. This phenomenon makes it possible to provide very precise dating of recent years (to within one or two years in the best case), used for dating wine, for example.
Is radiocarbon dating relevant to tribal art?
Radiocarbon dating is relevant to Tribal Art, because carbon 14 can absolutely differentiate between objects made from materials that lived before or after 1954. Carbon 14 clearly identifies copies and fakes. Moreover, this analysis is equally effective for older cultures (Dogon, Tellem, Djennenké, for example). Finally, thanks to augmented carbon 14, an innovative method developed by CIRAM and presented in a future article, we can reduce the intervals between the 18th, 19th and early 20th centuries to a few decades.
The place of science in the art market
Whether for the art market or archaeology, carbon-14 dating is a major advance. Over the years, this analysis has become a precious and indispensable tool for CIRAM laboratories.
Carbon 14 dating is particularly useful for detecting fakes in tribal art, for example.
But these scientific "tests" must be combined with a historical and stylistic study of a work. It is important to maintain a global and comprehensive approach to deliver accurate and reliable results. Carbon-14 dating should be used as an objective aid to decision-making, not as an imperative.
