Previous research has shown that age curves can be created for certain ink formulas as long as there is a change in the extraction characteristics of ink over time. Once standard aging curves have been developed, it will be possible to indicate a probable time period in which a questioned document was produced, even if only a limited amount of questioned material is available. A recent advance of the U.S. Bureau of Alcohol, Tobacco, and Firearms involves an annual tagging system of ink. This system allows a more precise determination of the first date of production of an ink formula. In the current study, standard aging curves for inks commonly encountered on documents were created. After completing graphs for each ink, several inconsistencies were apparent. Shapes of some of the graphs did not conform to theoretical results, and many experiments were repeated. These experiments showed that reproducibility and reliability were critical and that variation in sampling techniques or extraction time could easily create differences in the resulting age curves. Additionally, accurate sampling was absolutely necessary to ensure that each group of ink plugs contained the same amount of ink. 11 references and 6 figures