Dating ink on paper
SDS is routinely involved in writing Ink and Paper analysis and has been involved in many cases where this evidence has been beneficial.
Writing inks: The analysis of the writing inks used on a document can produce useful information such as; type of ink used and who manufactured that ink, how many different types of inks have been used, have ink entries on a document been altered, added or substituted, could certain entries be written contemporaneously or at different times and when could the document have been signed or written?
Having the entire library digital also opens up the possibility of sharing ink information worldwide. The group is researching it calls dynamic ink dating — an attempt to measure the precise dryness level of an ink, which can help to pinpoint the date it was applied.
This is done through gas chromatography-mass spectrometry: While the research aims to expand the reach of the world's largest ink library, the ink fingerprinting continues, whether for a Babe Ruth baseball, a fraud case, or even a ransom note.
And while they're already looking at paper and ink, analysts spend time inspecting the document as a whole, whether for watermarks, brighteners, branding on the paper, toner or defects that can help trace the machine that printed the document.
The International Ink Library is in the midst of moving to a fully digital catalog, which will exponentially speed up the effort to match inks.
These techniques are used and have been used in a number of prominent cases including the War Crimes Cases, Homicide Cases, Fraud cases and Pharmaceutical Extortion Cases (Panadol/Herron extortion case).
This is the most common type of investigative request the library receives.You might not know, however, that it also keeps a one-of-a-kind International Ink Library with more than 11,400 specific writing ink fingerprints on hand.The ink library handles a variety of cases, from threat letters — the Secret Service protects not only the President but also other high-profile government officials — and ransom letters, baseballs, and phony documents where someone is "trying to obscure the truth in some way," says Joseph Stephens, ink library document analyst.Non destructive techniques are used in the first instance and involve microscopic, variable wavelength light source illumination techniques (Polilight etc.,) and lasers to examine the inks on the documents.
The use of different wavelengths of the electromagnetic spectrum provides an examiner with a large number of different techniques to determine the optical properties and some of these techniques are used routinely to reveal, faded, erased and obliterated entries (pencil and ink ) or used to examine damaged documents which have been burnt, water or solvent affected or even digested!Using solvents, Secret Service analysts can separate individual bands of color, or dyes. It may be a mix of multiple purple and yellow dyes, or some other combination, so don't believe your naked eye.