Forensic Investigation on Blue Stamp Pad Inks using UV - Visible Spectroscopy

Stamp-pad inks are frequently used in numerous authorized documents particularly in contracts, wills, declarations, cheques and postal cards etc. These inks and stamps used to provide authenticity and credibility to document. Any alteration in stamp inks can dispute the document or question its authenticity. To establish the authenticity of a document, examination of stamp pad inks can play a pivotal role in forensic investigation for the purpose of legal procedures. In the present study, a total of 13 samples (B1 to B13) of blue stamp pad inks of different brands were collected from Punjab region of North-West India. Four different substrates were utilized including A4 sheet, bond paper, ivory paper, and postcard envelop to analyse the effect of substate on stamp pad inks. The stamp pad ink samples were analysed using UV-Visible Spectroscopy which is rapid, cost effective method. On the basis of visual peak asesement three samples of inks were selected for substrate study (B3, B11 & B12). The result revealed that blue stamp-pad ink samples were distinguished from each other with a discriminating power of 83.33% using visual examination and UV/Visible spectra. The findings provide insightful information about blue stamp pad inks differentiation which further help in forensic document examinations.