NCJ Number
159690
Journal
International Journal of Forensic Document Examiners Volume: 1 Issue: 2 Dated: (April-June 1995) Pages: 94-98
Date Published
1995
Length
5 pages
Annotation
A procedure for determining the relative age of inks used in writing is described that allows all three of the current methods to be performed in sequence using the same high-performance thin-layer chromatographic plate and the same samples of ink.
Abstract
Development of the three methods began in the late 1970's by Antonio Cantu at the Bureau of Alcohol, Tobacco, and Firearms and later by the author. These methods include (1) the R-Ratio Method, which measures the rate in which inks are extracted from paper using weak solvents; (2) the Sequential Extraction Method, which measures the percent of ink extracted by a weak solvent during a specific amount of time; and (3) the Dye-Ratio Method, which measures changes in the relative concentrations of dye components in ink extracted in a weak solvent. The age of the ink is estimated by comparing the results obtained from questioned and known dated inks using any one of these methods. The new procedure is important, because the power of the three methods varies, depending on the type of ink and paper examined. Another technique is an accelerated aging technique for estimating the age of ink when known dated inks are not available for comparison. Figure, tables, and 7 references (Author abstract modified)