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Document Examination Techniques and Equipment

Learn about the various mechanical devices and machines encountered by document examiners, such as computers, typewriters, photocopiers, printers, and fax machines. Discover methods used to detect alterations, erasures, obliterations, and indentations, including microscopic examination, UV or infrared light, digital image processing, oblique lighting, and electrostatic detection apparatus. Explore techniques like infrared luminescence and ink chromatography, as well as the analysis of paper qualities, watermarks, and evidence for handwriting analysis. Find more information and resources on document and handwriting analysis.

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Document Examination Techniques and Equipment

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  1. Question Docs Part 2

  2. Linguist Language that is used can help to establish the writer’s age, gender, ethnicity, level of education, professional training, and ideology. Unabomber Case

  3. Typescript Comparisons There are several mechanical devices and machines a document examiner encounters Computers Typewriters Typewriter ribbon Photocopiers Printers Fax machines

  4. Document Alterations • Obliterations—removal of writing detected by: • Microscopic examination • UV or infrared (IR) light • Digital image processing • Indentations can be detected by: • Oblique lighting • Electrostatic detection apparatus

  5. Alterations, Erasures, and Obliterations Erasure, either using an Indian rubber erasure, or with chemicals. Changes can be seen using microscope or direct or side lighting.

  6. Alterations, Erasures, and Obliterations Examiners often use Infrared Luminescence. When some inks are exposed to blue-green light, they absorb the radiation and reradiate infrared light, making any alterations visible with infrared sensitive film. Infrared luminescence can also reveal writing that has been erased.

  7. Infrared Luminescence examples

  8. Alterations, Erasures, and Obliterations Obliteration is the act of blotting or smearing over a writing or printing to make the original unreadable. The contents of a charred document can sometimes Be revealed through infrared photography.

  9. Other Document Evidence Indented writingsare the impressions left on papers positioned under a piece of paper that has been written on. Sometimes the document is readable with oblique lighting, or angling the document against the light.

  10. Other Document Problems Electrostatic chargecan be applied to the surface if the indented document, then layered with toner powder to produce an image.

  11. Ink Chromatography--physically separates mixtures of gases, liquids or dissolved solids. Types • Gas Chromatography • HPLC--high-performance liquid chromatography • TLC--thin-layer chromatography • Paper Chromatography

  12. Specialized Ligthing

  13. Paper Differences • Raw material • Weight • Density • Thickness • Color • Watermarks • Age • Fluorescence True Watermark Forged Watermark

  14. Other Document Problems Paper examined under a microscope can reveal: Fibers Fillers Pigments Additives Non-coated Coated

  15. Evidence • Class characteristics may include general types of pens, pencils or paper. • Individual characteristics may include unique, individual handwriting characteristics; trash marks from copiers, or printer serial numbers.

  16. More aboutDocument Analysis For additional information about document and handwriting analysis, check out Court TV’s Crime Library at: lwww.crimelibrary.com/criminal_mind/forensics/literary/1.htm Or forgery cases at: www.crimelibrary.com/criminal_mind/scams/lincoln_forgers/index.html

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