Tools & Apparatus
The most important tool a document examiner has is his or her own vision, but the external tools enable the examiner to evaluate and record more than is apparent to the unaided eye. Technology and instrumentation are a great aid to the document examiner. Magnifiers and Microscopes make small details visible and measurable. Combining those devices with cameras allows the examiner to study and compare images and to present illustrations to fact-finders. A variety of specialized light sources extend the examiner’s eyes into portions of the electro-magnetic spectrum where they cannot go unaided. The most useful areas of the spectrum for the document examiner are the Ultraviolet and Infrared wavelengths, which allow the differentiation of similar appearing inks and the review of normally invisible security features. And, speaking of invisible, EDD (electrostatic detection device) equipment reveals and demonstrates “indented writing.”
Magnifiers
There are several types of magnifiers available. A stand magnifier is excellent for any type
of
work because the magnifier body is its own stand. Your hands are free for other tasks.
Illuminated stand magnifiers have two parts – the head and the handle. There are heads
available
at several magnifications (3X, 4X, 5X, 6X, 7.5X, 10X, 12.5X). The images be low were taken
with
increasingly stronger magnifiers – 4X, 7X and 10X.
Digital Imaging System
Digital imaging technology provides a fast and cost-effective alternative in capturing and storing document images by using conventional photographic techniques. Once images are captured, digital filters can be used to restore obscured information on a disputed document. Images viewed through a microscope are recorded with analog or digital cameras. Dye-sublimation, inkjet and laser printers are used to generate photo-quality color prints.
Microscopes
The most important instrument in the document examiner’s arsenal is the optical microscope.
Usually, critical evidence attesting to the genuine or spurious nature of a questioned
document cannot be seen by the naked eye. The stereo-microscope provides a 3-dimensional
view of an area of interest.
Document examiners use a wide range of magnification equipment. Handheld magnifiers enlarge
the material from 2 to 10 times (magnification powers of 2x to 10x) and may have lighting
abilities as well to brighten the field of view.
To see details more closely, there are many types of microscopes. A binocular, or stereo,
microscope is comfortable to use because, as the name implies, there are 2 eyepieces and the
viewer focuses with both eyes. In addition, a microscope can have a third viewing tube which
allows a still or video camera to be attached for “through the microscope” photography.
Digital microscopes combine optics for magnification with digital capture technology to
allow the user to view the magnified image on the monitor instead of or in addition to
viewing it through the microscope eyepieces. Specialty microscopes, such as a document
comparison microscope, perform additional specific tasks.
It might seem that the more powerful the microscope in terms of magnification, the better,
but for the task of handwriting examination, this is not the case. Most handwriting
examination is done at powers of 10x to 50x (the subject is enlarged 10 to 50 times). When
magnification is higher, the field of vision is so narrow that the object viewed loses
relevance.
It is a good idea to start out with a low power when first examining a portion of a document
and then to zoom in closer to the area you want to inspect.
A type of microscope that is particularly useful in document examination is the comparison
microscope. Two documents can be viewed side-by-side and the images can be positioned so
that they appear to overlay each other. By using a different color of filter on each
document, the examiner can then see a third color in those areas where the two segments
being compared overlap each other.
Infrared/ Ultraviolet Radiations Apparatus
A special instrument for document examination is a UV/IR spectral comparator which makes use
of electromagnetic wavelengths and various filters to differentiate inks and reveal hidden
material on documents. The application of chemical eradicators, the removal of information
with erasers or the application of foreign adhesives can affect the fluorescence of document
materials. Ultraviolet light sources are used to detect the presence of erasures and to
locate foreign adhesives used when repairing documents or resealing envelopes. Written
entries erased by chemicals or erasers and the application of adhesives can often be
restored by examining suspect documents under ultraviolet light.
This demonstration parallels many cases in which additions to documents can be detected by
the use of Infrared absorption or luminescence examination.
Ultraviolet examination is also useful in the examination of documents. Here, UV reveals
fluorescent security fibers embedded in the paper of many currencies. There are many other
types of examinations possible with spectral comparators.
Indented Writing
The Electro-Static Detection Apparatus (ESDA) provides the document examiner with a non-destructive technique for detecting impressions in paper that are invisible to the naked eye. The ESDA can also reveal the relative sequence of entries in ledgers, journals or medical records.
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Deepak Jain
Laywer’s Chamber No. T-20
Tis Hazari Courts
Delhi-110054 (India)
expertdeepakjain@gmail.com
+91 98110 76635
+91 98990 76635