The study found that the irradiation process had very little effect on the chemical analysis of writing inks. Of the 97 different inks subjected to electron beam irradiation, none changed with respect to dye composition due to the irradiation. One control ink did show some minor changes in optical properties and dye characteristics over time while the irradiated sample remained stable. Significant changes were observed in the ultraviolet fluorescence characteristics of the irradiated papers sample themselves, but not the inks. These findings apparently contradict earlier studies conducted on a more limited sample set. Comparisons of current findings with other studies are difficult because it is not possible to determine accurately the radiation dosages to which the inks were exposed during processing. Approximately 97 different black, blue, red, green, and yellow writing inks were selected for the study. Writing ink types included ballpoint, gel, plastic/felt tip, and rollerball. All noncontrol samples were subjected to standard mail irradiation conditions used by the U.S. Postal Service at the time this experiment was performed. A video spectral comparator and thin-layer chromatography analysis were used to evaluate both the control and the irradiated samples. The context for this study was the earlier finding that the use of the electron beam irradiation process to destroy biological agents sent through the mail produced adverse effects on writing inks used on the envelope and enclosed paper. Irradiation dosages have been reduced since then. 7 figures, 2 tables, and 13 references