Forensics age dating ink

There are two types of fountain pen inks: (1) iron-gallotannate type and (2) aqueous solutions of synthetic dyes.Modern inks of type (2) contain synthetic blue dyes to provide an immediate blue color to the ink which gradually turns black after oxidation on paper.Benzyl alcohol is also commonly used as the vehicle (solvent) by some ink manufacturers.Chelated dyes (introduced commercially around 1953) are stable to light.The composition is basically the same, but this ink does not become fluid until disturbed by the rotation of the ball point in the socket.Cartridges containing this ink are under the pressure of nitrogen or some other inert gas.This explains the origin of the name blue-black fountain pen ink. This ink is insoluble in water and cannot be effectively erased by abrasion.

This is done by: (1) comparing the rates and extents of extraction of questioned and known dated inks in organic solvents by thin-layer chromatography (TLC) densitometry; (2) comparing changes in dye concentrations by TLC and TLC densitometry; and (3) comparing the volatile ink components by gas chro-matography-mass spectrometry (GC-MS).These inks are bright and attractive in color, but they are not nearly as stable as the carbon or blue-black inks.Some of the synthetic dyes used fade and are soluble in water.When dating tags are detected, it is possible to determine the actual year or years when the ink was manufactured.Dating tags are unique chemicals that have been added to ball-point inks by some ink companies as a way to determine the year the ink was made.

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