NCJ Number
186067
Journal
International Journal of Forensic Document Examiners Volume: 5 Dated: December/January 1999 Pages: 68-70
Date Published
1999
Length
3 pages
Annotation
Successfully determining the age of an iron-based ink is dependent to a great degree on the operating conditions and the application of the chemicals necessary to observe the sulfate diffusion; the purposes of this paper are to define and validate a proper method of analysis and to increase the rate of success when using this method to observe sulfate diffusion.
Abstract
Although the method that is used in determining the age of a document through the surviving degree of sulfate's diffusion is not a new technique, it has not been used efficiently because many examiners often ignored the dissolving loss of lead sulfate deposition and could not successfully develop the image of sulfate diffusion. The paper first explains the factors involved in the lack of image development in sulfate diffusion. It then suggests improvements in the traditional sequence of chemicals used according to the same principles of ionic effect. It also describes a suitable method for dealing with the written stroke on paper by using this new chemical regime. The results reduce the dissolving loss of the sample to a minimum. This new approach has been used successfully in 20 cases in China, where the iron-based ink containing sulfate and sulfuric acid are more common. The factors that affect the degree of sulfate's diffusion are identified and discussed. 2 figures and 7 references