Infrared forensics on paperWith infrared light, forensic investigators can tell you whether a document is a forgery or whether paper currency is counterfeit. Now the boundaries of infrared forensics a…
Infrared forensics on paper
With infrared light, forensic investigators can tell you whether a document is a forgery or whether paper currency is counterfeit. Now the boundaries of infrared forensics are being pushed into uncharted territories by researchers at the Lawrence Berkeley National Laboratory in and the results are promising for criminal and antiterrorism investigations, as well as for historians and archaeologists.
In their most recent study, published in the June 2002 issue of the Journal of Applied Spectroscopy, Dale Perry, Michael Martin, Wayne McKinney and Tom Wilkinson worked with the US Secret Service to demonstrate the effectiveness of synchrotron-based IR spectromicroscopy on inks.
“The Secret Service is interested because they can use IR data on ink to identify the possible origins of a document, verify that the document is as old as it claimed to be, and check if the same ink is used throughout a document,” says Perry. “IR data is also potentially effective for identifying chemical aspects in other ink-based items such as currency and stamps.
In the past, characterizing ink on paper has been a daunting task. “We overcame these problems using ALS IR photons at wavelengths of 2.5 to 25 microns to characterize ink samples,” says Perry. “Our light beam was so intense we could make rapid and direct spectromicroscopic measurements of the inks without having to chemically separate them from paper.”
In his words, this method has a “bright outlook” as a forensics tool.
Excerpts from scienceBEAT at Berkeley Lab http://www.lbl.gov/enews/8-26-02.html#text2#
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