Forensic science ink dating
Iron-based inks can be dated by measuring the migration of iron along the fibers of the paper by Scanning auger microscopy.
This article describes state of the art procedures for the chemical and physical comparison, identification and dating of inks on questioned documents.
The validity of documentary evidence is of paramount interest in many different types of litigation (and all of these situations are actual cases in which Federal Forensic Associates has provided examination, consultation and testimony).
With advances in technology, many documents that could not be analyzed five years ago are now possible sources of important information, such as the answers to questions relating to the method and time period of preparation. Lyter began his career as a forensic chemist for the Bureau of Alcohol, Tobacco and Firearms, National Laboratory Center in Rockville, Maryland.
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).
In cases where known dated writings are not available for comparison with questioned inks, accelerated aging (heating the ink to induce aging of the ink) can sometimes be used to estimate the age of ink using any or all of the above described techniques.
Several other ingredients are usually added to the ink to impart specific characteristics.
These ingredients consist of fatty acids, resins, surface active agents, corrosion control ingredients and viscosity adjustors.
Chemical and physical analysis of inks on questioned documents provides valuable information regarding their authenticity.Knowledge of the composition of inks is necessary to understand the reasons for the various methods used to analyze inks.Also, knowledge of the first production date for each type of ink or certain ingredients in the inks is useful for dating inks. Lyter is President and Chief Scientific Officer of Federal Forensic Associates, Inc., where he applies his knowledge, training, and experience in matters of forensics science, including ink and paper analysis, trace evidence and questioned document examination.Qualified trace evidence areas include fire debris, explosives, paint, hair, fibers, glass and wood. Chemistry, Oklahoma City University Diplomate of the American Board of Criminalistics Microscopy for Pigment & Fiber Identification in Art & Artifacts, Campbell Center for Historic Preservation Studies, 2010 Surface Analysis Techniques, Physical Electronics, 1992 Canon Facsimile Workshop, American Society of Questioned Document Examiners, 1991 Identification of Photocopiers, New Mexico State Police, 1983 High Pressure Liquid Chromatography, Waters Associates, 1978 High Pressure Liquid Chromatography, American Chemical Society, 1978 Forensic Microscopy, Mc Crone Research Institute, 1978 Questioned Documents, United States Secret Service, 1977 X-ray Spectrometry, State University of New York, 1976 Fiber Microscopy, Institute of Paper Chemistry, 1975 American Academy of Forensic Sciences - Fellow Mid-Atlantic Association of Forensic Scientists California Association of Criminalists American Board of Criminalistics Southwestern Association of Forensic Document Examiners International Association of Forensic Sciences American Chemical Society Society for Applied Spectroscopy American Society for Testing and Materials Comparison of Paper Samples — IAI News, 1976 Comparison of Typewriter Ribbon Inks by Thin Layer Chromatography — Journal of Forensic Science, 1977 A Scientific Study of Pencil Lead — Journal of Forensic Science, 1978 Analysis of Water Soluble Paper — Journal of Forensic Science, 1980 Comparison of Typewritten Carbon Impressions — Journal of Forensic Science, 1982 Examination of Ball Pen Ink by High Pressure Liquid Chromatography — Journal of Forensic Science, 1982 Ink Analysis, A Key Element in Questioned Document Examination — Trial, 1983 A High Performance Liquid Chromatographic (HPLC) Study of Seven Common Explosive Materials -— Journal of Forensic Science, 1983 Finding Fraudulent Documents — Family Advocate, 1989 Attempted Determination of Authorship by Ball Pen Line Characteristics — Forensic Science International, 1990 Analysis of Writing Ink — chapter in the book HPLC in Forensic Science, 1982 Contributions to the book Forensic Ink and Paper Examination by Brunelle and Reed, 1982 Examination of Gel Pen Ink by Microspectrometry — Journal of the American Society of Questioned Document Examiners, December 2005 Examination of Gel Pen Ink by Physical and Thin Layer Chromatographic Examination — Journal of the American Society of Questioned Document Examiners, December 2005 Ph.
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.