Instrumentation for Document Examinations
During my career, I have noted the transition from examinations of typewritten and faxed documents to computer printed and scanned documents. Thankfully, technology evolves as well and is used by document examiners in their analysis of inks, security features, indentations and other examinations as needed.
Foster and Freeman is one reputable company specializing in laboratory instruments. They offer various types of instruments to resolve questioned document issues. A widely used instrument they offer is the Video Spectral Comparator (VSC). Different models offer different levels of complexity to facility the examination needs of the purchaser.
Two examples of specialized document examination equipment are shown below.
Video Spectral Comparator 4Plus
(Courtesy of Foster & Freeman)
The multifaceted testing capabilities of the VSC 4Plus include differentiating inks (common to alterations), verification of security documents, visualization of UV activated inks and fibers, watermarks and surface features of paper (embossments, intaglio printing, etc.)
Indented Writing Materializer
Although not commonly considered, indented writing on documents may provide important evidence in questioned signature or handwriting cases. The document is placed on top of the instrument, covered with a polymer film and an electrostatic charge applied. A black powder is brushed onto the surface, attracted to the indentations present. Once the process is completed, an adhesive film is applied to the polymer film, preserving the evidence obtained without causing harm or marks on the questioned document.
Other laboratory instruments are available and utilized appropriate to individual case needs.