Advances in the forensic analysis and dating of writing ink
However, the FTIR technique requires prior time-consuming sample preparation when used for the analysis of writing inks.
Moreover, there are some difficulties related to the presence of strong absorption bands caused by paper overlapping with the absorption bands of an ink .
In a variety of cases, in order to hide the fact of falsification, documents are heated or exposed to artificial or natural light sources.
Thus, the disclosure of such falsification is an important legal and social task [1,2].
All writing inks consist of a dye component or a mixture of dyes, as well as a binding substance known as a vehicle composed of several solvents and additives responsible for the physicochemical properties of inks (including lubricants, corrosion inhibitors, emulsifying agents, buffers, surfactants, and various other components) [2,3,4].
All ingredients in the ink mixture can yield important analytical information to the forensic document examiner.
Methods of attenuated total reflectance Fourier transform infrared spectroscopy (ART-FTIR) are also often used in this regard.
This work is devoted to the extremely popular but poorly developed scientific and forensic problem of the estimation of the actual dates of inscriptions placed on paper and made by ballpoint pens.
It is shown that the degradation of writing inks with time may be controlled via Raman spectroscopy and gas chromatography.
Thus, a variety of processes occurs simultaneously when writing inks are printed on paper.
Writing inks dry due to solvent evaporation; they get dull due to dye degradation and solidify due to resin polymerization.