Preliminary Studies on the Absorbance Ratio Method Used to Determining the Age of Stamp‐pad Ink Seal

Abstract

Stamp‐pad ink seals are often placed on important documents, and determining the dating of stamp‐pad ink seal is important to assess the authenticity of a document. In this study, 20 different brands and types of stamp‐pad inks were classified by ultraviolet visible spectrophotometer. Six different brands and types of papers were classified by micro‐Fourier transform infrared spectrometer and visual spectral comparator 6000. Three different brands of stamp‐pad inks and two different types of paper were used to make diachronic samples of the seals. A method was employed to date the stamp‐pad seals by comparing absorbance ratios and inks of known age. Curves were created to show the relationship between the absorbance ratio of ink and the age of the seals. The experimental results showed that the absorbance ratio method was applicable for the relative dating of stamp‐pad ink seals in some cases where the seal was placed on the document within 10 weeks.

Interpol questioned documents review 2019–2022

“…including any other technology used to prepare the document. The following 64 articles [ [548] , [549] , [550] , [551] , [552] , [553] , [554] , [555] , [556] , [557] , [558] , [559] , [560] , [561] , [562] , [563] , [564] , [565] , [566] , [567] , [568] , [569] , [570] , [571] , [572] , [573] , [574] , [575] , [576] , [577] , [578] , [579] , [580] ] [ [581] , [582] , [583] , [584] , [585] , [586] , [587] , [588] , [589] , [590] , [591] , [592] , [593] , [594] , [595] , [596] , [597] , [598] , [599] , [600] , [601] , [602] , [603] , [604] , [605] , [606] , [607] , [608] , [609] , [610] , [611] ], combined with 17 presentations [...…”

“…In their study, Ouyang et al [ 575 ] used the absorbance ratio method to determine the age of an ink-stamp impression. The extraction solution of the stamp ink is analyzed by UV–Vis spectrophotometer after 3 min and 30 min to obtain the absorbance ratio.…”

Forensic Dating of Official Documents: Utilizing Ftir Analysis of Stamp Pad Ink Degradation for Document Authentication

“…Consequently, the forensic examination of stamp pad ink becomes essential in determining the true age of questioned documents. Numerous research efforts have focused on tackling this issue using various analytical techniques such as UV-Vis spectrophotometry [1], Visible near infrared reflectance spectroscopy [2], High-Pressure Liquid Chromatography, GC/MS methods [3], digital microscope, and Raman spectroscopy [4], Gas Chromatography [5], MECC-DAD and CZE-ESI/MS [6], Confocal Raman Microscope [7], HPLC [8], FTIR [9], TLC [10] [11], and Raman Spectroscopy [12], LD-IMS [13].…”

Determining the age of documents based on the stamp and seal impression

“…9 The smallest number of papers is dedicated to determining the age of a document based on the stamp impression. They describe physicochemical methods of using ultraviolet visible spectrophotometer 10 or Raman spectroscopy and gas chromatography 11 when studying the paper's ink absorption at the moment of impression. Those experimental studies are done in strictly controlled conditions and their implementation represents a great challenge for the modern judiciary when it comes to diff erent types of ink, paper, or conditions under which certain documents were stored and possibly mechanically altered.…”