A systematic approach to identification of writing inks is presented. This approach uses a multiple technique method for analysis of the inks to develop a large number of identifiable points for comparison. Well established methods are used for the analysis of inks, such as thin layer chromatography, spectrophotometry, and gas-liquid chromatography, in addition to traditional methods for comparison which use ultraviolet and infrared light. The inks are identified by comparing the results of the questioned inks with results obtained from a complete library of writing inks maintained by this laboratory. By using the described approach, most inks can be identified with a high degree of certainty.

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A controlled study was carried out on 600 samples of various types of white and colored paper obtained from 10 different paper manufacturers with known production histories and dates. Neutron activation analysis was employed to measure the characterizing trace elemental compositions. Results indicated that (1) the papers examined were uniform with respect to their trace elemental compositions, (2) papers produced by different manufacturers are readily distinguishable qualitatively and/or quantitatively, (3) different batches of paper produced by the same manufacturer are generally qualitatively similar if produced within a short span of time (however, these specimens can be distinguished by quantitative analysis of the trace elements), and (4) different batches of paper produced by the same manufacturer at least 1 year apart are readily distinguishable qualitatively and/or quantitatively.

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