By the combination of the presence or absence of each tag either a specific year or a range of years could be established.
The procedure most commonly used for the detection, isolation, and analysis of these date tags in ink dating is: The comparison between the known tag and the questioned ink being examined should focus on whether the florescent compounds are the same color in the known and questioned.
The fact that two inks are indistinguishable does not prove that they both came from the same pen as a large number of pens are likely to hold indistinguishable ink either because they originate from the same manufacturer or because, by chance, they contain closely similar ink.
These ink dating methods include the comparison of the examined ink to a known library of standards, commonly called the library approach, the detection of chemical date tags placed in the ink purposefully by the manufacturer, commonly called the date tag method, and also the determination of the type of ink writing instrument used.
The determination of the type of writing instrument is probably the oldest method of ink dating.
The first ink dating method is the static approach, which determines when the ink being examined was manufactured.
The second ink dating method is the dynamic approach, this method is to determine when the writing occurred, or in simple terms, how long the ink has been on the paper.
However, since this is a very small portion of the actual type of cases seen, we will concentrate primarily on more recent developments.
Other pages discuss the use of infrared to discriminate the differences between inks that visually and microscopically look identical.
Differentiating inks can be important in cases where a document is suspected of having been altered.
A classic example is where a zero is added to a cheque making the value ten times as much.
LGC is fortunate in having the backing of its world renowned analytical chemistry section.
This means that we can use high end techniques to examine inks such as Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry.
The visual appearance of inks is only one clue to their composition.