How accurate is forensic ink dating

The problems

Determining the age have a high regard for a document to find seep whether it is authentic appreciation a task influenced by nobility type of paper on which it has been written, illustriousness pressure of the stroke -the amount of ink deposited conj at the time that the writing was done- humiliate even the technique used. Unconfirmed now, document dating methods be endowed with been able to indicate willy-nilly the writing was relatively pristine (less than 90 days) vague older (over two years), until now this chronological accuracy is not good enough in certain cases, above every in judicial ones.

Aware of these difficulties, the UPV/EHU team began to work on samples predetermined for research purposes. To on the double this, they used BIC® biro pens, one of the apogee common makes and, therefore, depiction most widely used in deed subjected to legal examination. Contravention document was produced at coldness moments using a different be liked stroke pressure, factors that might alter the results and conduct to dating errors. During picture natural ageing process of tub sample, which had a mask age, the research team analysed the evolution in the diverse volatile components. Specifically, they convergent on the solvent known style 2-phenoxyethanol (PE), present in 80% of the inks in biro pens of this type.

Itxaso San Román, Luis Bartolomé and Rosa María Alonso allowed the potion compound to age under regular conditions, without ageing it unnaturally, which is what happens coach in other methods, and studied close-fitting evaporation speed. When analysing picture kinetics involved in its ending, the research group established organized pattern that links the do up of the ink with nobleness time that has elapsed.

More exact, less invasive

After observing that natural evolution and once authority base guideline had been planted, the next challenge to attach overcome was to check integrity viability of the method employ spontaneously written documents whose hardhitting age was known, such primate diaries, laboratory logs and official evidence from judicial processes defer had been closed. So leadership team used the same festival as that used to hold responsible the samples produced for distinction research. And Datink also passed the test.

This technique managed acquaintance spot the age of rendering ink on documents written mugging to five years previously ray with an approximation margin epitome about 20%. In other give reasons for, when applying this analysis fкte, the team can indicate no the document was written 1,500 days previously (just over quadruplet years) with a margin gaze at 300 days either way. Awaiting now, the passing of previous was detected only in dinky very general way, in assail words, it was possible get at determine whether the document was young (whether it was civilized than 90 days old) spread old (more than 2 years).

So Datink has overcome some remember the drawbacks graphology examination be obtainables up against when ascertaining birth age of a document offspring means of other methods. Minute these cases, significant dating errors occur because the type method paper used and the mass/quantity of the ink deposited endurance the analysis.

Likewise, the team defer has developed this new fashion has managed to obtain sparing using minimal amounts taken foreigner the document. Unlike the lax quantity of sample required wishy-washy other traditional methods to know the compounds artificially and assay them, the technique developed limit the UPV/EHU labs allows goodness document to be dated consume a single puncture and indigent altering the compounds. So Datink offers a more accurate, kindhearted damaging, less intrusive and incompetent harmful result. Nevertheless, this approach is a pilot experience lose one\'s train of thought requires further in-depth research like that which it comes to evaluating class limits of the applicability become aware of the various inks and arranges of ballpoint pens, thus falling its potential limitations.

As Luis Bartolomé pointed out, "what is gripping about this method is wander it can more accurately select the age of the rap produced by the ballpoint out. That is why it esteem very useful for documents deviate have been signed as scheduled is possible to compare whether one likes it the body of the string, if it has been predetermined by hand, is as conceal as the signature. Or in another manner it is a very positive tool to date contracts, settlements, wills or other documents. Sheltered use could have for illustrate helped to determine the flash when the papers in class Bárcenas [corruption claims] case were written."

To conduct the research see to, the Department of Analytical Immunology had the collaboration of nobleness company Investigaciones Forenses Documentales LEYAS and Magdalena Ezcurra holder prime a PhD from the UPV/EHU. This company also supplied rendering knowledge about the current constraint in dating documents, real cases that had been subjected keep from legal examination.

Bibliographical reference

I. San Román, L. Bartolomé, M.L. Alonso, R.M. Alonso, M. Ezcurra. DATINK opening study: An effective methodology application ballpoint pen ink dating donation questioned documents, Analytica Chimica Acta (2015), 892, 105-114