Abstract: A method and ink composition are disclosed that utilize two mechanisms for the purpose of indicating the approximate age of an ink that has been deposited on a writing surface. The first mechanism relates to detecting color shifts of pH sensitive compounds in the ink as the result of the evaporation of certain acidic or basic chemicals thereof. The second mechanism relates to the oxidation of compounds in the ink. Spectroscopically generated curves are plotted as the ratio of reactants to products, versus time. The spectral characteristics of the ink are determined in units of percent reflectance of the active compounds in the ink so that the age of the ink can be computed by reference to known reaction rates. A plurality of dyes having differing reaction rates may be added to the ink to enable precise measurements to be made over different time intervals.

Abstract: An apparatus and method to enable investigators of medical and insurance fraud to quickly and reliably determine whether a plurality of signatures affixed to a series of documents were made with the same pen and/or at the same time. According to a first embodiment, a series of indentations are formed around the periphery of the rim at the forward end of a conventional ballpoint pen. The indentations produce radially inward extending projections which are aligned with the rolling ball of the pen to induce scratches or micro-striations in the ink lines applied to the paper from the ball. By analyzing the scratch patterns of different signatures applied by the same maker to different documents, an indication can be provided whether the signatures were all made with the same pen.