"Looking outside the visible spectrum, some of the inks will disappear and come transparent," Stephens says. We can determine the number and type of inks to categorize inks into classes."The final leveling of testing, which happens at the chemical level, involves what's called thin layer chromatography.
This process separates the ink on a thinly coated piece of paper.
In those cases where non-invasive examination is unable to provide sufficient information to address the questions raised, it may be necessary to consider invasive paper and/or ink analysis and FDS can put you in contact with specialists in those fields.
Invasive examination techniques require samples to be taken from the document.
Therefore, it is important to remember that all non-invasive forensic examinations and comparisons must be completed prior to invasive examinations in order to avoid loss of potential evidence.
A surgeon was defending a medical malpractice suit and produced three pages of patient medical records in support of his case that he had cautioned the plaintiff patient as to the risks associated with a proposed medical procedure.
Certificates of qualification and registration held by the person were submitted to our laboratory as part of the investigation.
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.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."The chemistry of ink is such that it is rare that the color the human eye perceives is the color the dye is that is used," Stephens says.By comparing the bands to the over 11,400 inks in the library, the analysts can pinpoint the manufacturers creating the specific ink.The warning appeared on page 2 of the n Notwithstanding the gradual decline in the use of cheques, the intercepting of cheques between being filled out and being banked (often while in the mail but sometimes by a person on the inside) is an ongoing problem.A dispute arose as to the genuineness of certain Platinum Certificates purporting to have been issued by the Union Bank of Switzerland.
The first — the physical tests — simply take stock of the type and color of ink.