Modern forensic document examination laboratories will be equipped with apparatus specifically designed for forensic document examinations such as the Video Spectral Comparator (VSC) and the Electrostatic Detection Apparatus (ESDA). This will be briefly discussed.
The Video Spectral Comparator
The Video Spectral Comparator (VSC) is an apparatus which can:
- analyse and compare inks: reveal alterations on a document;
- visualize security features printed into papers;
- use the spectrometer and various built-in light sources for U.V., visible spectrum and I.R. examinations of ink and documents to visualise fluorescence; examination with transmitted light or low angle light, and recording/comparing differences in reflectance, and absorption under variable wavelengths of light and with various filters which will discriminate between different inks.
The Electrostatic Detection Apparatus
The Electrostatic Detection Apparatus (ESDA) is an apparatus which can:
- produce an evidential record of any indentations (writing impressions) which are present upon a page, resulting from previous pages of over-writing in a writing pad, notebook, or upon a letter placed inside an envelope which was then addressed. The ESDA is very sensitive and may record over-writing impressions which passed through several pages;
- visualise and record any other transmitted impression, such as from a machine postal stamp upon an envelope; or visualise and record any paper edge impressions of a page-portion that was torn from a page within a note-pad, even if the page was removed some time later.
Other Types of Document Examinations
The most common types of document examinations will now be detailed.
Age of a Document
The earliest date a document could have been prepared can sometimes be determined by examining watermarks, indented writing impressions, machine- generated printing, and typewriting.
Altered or Obliterated Writing
The presence of physical alterations or obliterated writing can sometimes be determined, and the writing can sometimes be deciphered. Paper torn edges can sometimes be positively matched. The manufacturer can sometimes be determined if a watermark is present. Paper can be examined for indented writing. Do not rub the indentations with a pencil. Do not add indentations by writing on top of any evidential documents.
Burned or Charred Paper
Information upon burned or charred documents can sometimes be completely deciphered. The document should be minimally handled. The document should be shipped in the container in which it was burned, in polyester film encapsulation, or between layers of cotton in a rigid container.
Carbon Paper or Carbon Film Ribbon
Examination of used carbon paper or the carbon film ribbon of an electric typewriter can sometimes disclose the content of the text.
Embossings and Seals
An embossed or seal impression can sometimes be identified with the instrument that produced it.
Graphic Arts (Printing)
Printed documents can sometimes be associated as originating from a common source or identified with known printing paraphernalia such as art work, negatives, and plates.
Bogus documents which relate to one’s identity are often produced to support an application for passport, drivers licence, bank account or loan, or birth certificate. Our technology may illustrate the defects in bogus identity documents.
Photocopies can sometimes be identified with the machine producing them if the samples and questioned copies are relatively contemporaneous. The possible make and model of the photocopy machine can sometimes be determined by comparison with reference file.
Rubber Stamp Impressions
A rubber stamp impression can sometimes be identified with the rubber stamp that produced it. So submit the rubber stamp to the Laboratory un-cleaned.
Questioned typewriting can occasionally be identified with the typewriter that produced it. This is most common when the typewriter is a type-bar machine. The identification can sometimes be based on individual characteristics that develop during the manufacturing process and through use and abuse of the typewriter. Typewriters with interchangeable elements (ball, printwheel, or thimble), and carbon film or correction ribbons, can sometimes be associated with specific texts by examining individual characteristics of the elements and by correlating the text and ribbons.
Comparison of questioned typewriting with reference samples can sometimes determine a possible make and model of the typewriter and/or the typewriter elements. Carbon film typewriter ribbons can sometimes be read for content or specific wording of questioned material. Carbon film ribbons can be identified with questioned typewritten impressions. Fabric ribbons used more than once, cannot be read.
Paper is composed of numerous fibers. The randomness of the paper fibers is an identifying characteristic that makes fiber designs unique to a paper sample. The transfer of fiber designs can link a typewriter ribbon to typed text, which enables examiners to positively link a ribbon to text on a document. In the examples above, carbon was transferred (left) when the typeface struck the ribbon to the paper. A reverse transfer of the paper fiber design (right) is made on the plastic ribbon from the pressure exerted by the typeface.
Submitting Questioned Documents Evidence
Questions concerning documentary evidence should be directed to 0424 992 220.
- Documentary evidence should be preserved in the condition in which it was found. It should not be folded, torn, marked, soiled, stamped, written on, or handled unnecessarily. Protect the evidence from inadvertent indented writing. Try to avoid marking the document. If it is necessary, mark only a copy of it, or label it for identification purposes.
- Whenever possible, submit the original evidence to the Laboratory. The lack of detail in photocopies makes examinations difficult. Copies are sufficient for reference file searches.