Compound Specific Radiocarbon (14C) Dating of Our Colorful Past: from Theory to Practice

For generations, humanity has preserved customs, places, objects, artistic expressions, and values – our cultural heritage. The use of color on cultural heritage objects is ubiquitous and found on artefacts from prehistoric rock art to present day contemporary artworks. The chemical identification of the colored materials used within an artwork often provides information about the work's origin. At the simplest level, a comparison of the materials present with information on their first date of discovery indicates the earliest possible period in which the colored artefact was created. More precise constraints on the date of creation can be provided by radiocarbon (¹⁴C) dating, however until today no such analysis has ever been conducted on the compounds responsible for the object's color. The analysis of natural organic dyes and pigments is challenging, as the limited sampling access, their low concentrations and presence in highly complex matrix, are all major challenges to be overcome. The separation of intermingled carbon sources is without question the most difficult problem, yet feasible with the help of compound specific radiocarbon analysis (CSRA). Here, we discuss the potential of radiocarbon dating isolated natural organic dyes and pigments and explore new routes to date cultural heritage objects.