Documents- Instrumental

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  • Created by: s013693b
  • Created on: 03-05-14 23:06
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  • Documents- Instrumental
    • Non destructive document analysis
      • ESDA
        • Impressions of writing can be seen on the paper beneath
          • Disturbance of paper fibres
          • Strength of impressions depend on:
            • Writing instrument used
            • Pressure when writting
            • How many sheets down from the sheet which was written
          • Limitations
            • Soaking in water removes impressions
            • Secondry indentations can occur when two pieces of paper containing indentations come into contact
              • False conclusion that the papers were from one single stack
            • Sometimes ESDA fails to detect very deep indentations
          • Impressions can be enhanced by humidifying the document
            • Over humidifying can cause loss of impressions
              • Soaking in water removes impressions
        • 1. Electrostatic charge induced on paper surface
        • 2. Indented areas attract higher charge density
        • 3. Photocopier toner attracted to these areas
        • 4. Writing become visible
        • Depending on the depth of indentations ESDA trace is either lighter or darker than background
          • Shallower indentations appear darker against the background and vice versa.
      • Filtered Light Analaysis
        • Analysis of inks under verifying light conditions
          • Visually identical inks can show distinct properties under carrying light conditions
        • Low intensity
        • High Intensity
        • Untitled
      • Spectroscopic methods
        • Infrared
        • UV Visible
        • Raman
    • Untitled

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