Absolute dating of modern paper using ¹⁴ C bomb peak data of the paper fibers

This study demonstrates a method for absolute dating of paper using the 14 C bomb peak and combining AMS radiocarbon measurements of paper fiber mixtures with detailed qualitative and quantitative analysis of the fiber composition. Radiocarbon measurements were performed on fibers of 162 paper samples with known production years between 1950 and 2024, which originate mainly from Europe/Germany. Wood‐based paper fibers exhibit a radiocarbon signature that is less directly related to calendar years than that of annual plants or plant‐derived substances such as starch. However, the investigation shows that for specific fiber compositions, significant correlations exist between the 14 C concentration in paper fiber mixtures and the production year of the paper. Three main fiber composition types were identified: (1) papers mainly composed of hardwood pulp fibers, (2) papers with mainly softwood fibers, and (3) papers consisting of 90 to 100% eucalyptus fibers. The latter two fiber mixture types show the strongest correlation between the 14 C concentration and the year of the paper production, permitting the dating of papers with uncertainties of as low as 3–5 years. In contrast, papers of mainly hardwood pulp fibers show a more complex relationship. However, for certain fiber compositions and time periods, reliable dating of those papers is also possible. The dating procedure is based on 14 C reference data specific to each fiber mixture type and mathematical models that generate 14 C reference curves for specific fiber compositions. These models take into account assumed harvest ages for different tree species used in pulp production.