1. Methods for Analyzing Questioned Documents
Document Examination
Methods for Analyzing
Questioned Documents

2. Macroscopic Techniques
Reflected Light – observation of a document under normal lighting.
May reveal incorrect paper, incorrect pen, or format errors
Oblique-light – (side light or grazing light)
Reveals shadows from erasures, indentations, and embossments
Transmitted light – Use of a light box
Identify type of paper and watermarks
Detect erasures (thin spots in paper)

4. Microscopic Techniques
Stereoscope with power is most useful for document examination
Determine type of pen used
Detect retouching, pen lifts, tremor, erasures, corrections

5. Spectral Techniques Ultraviolet light
Fluorescence
Detect erasures and corrections
Enhance faint writing
Dissimilar glues or wax tampering on envelopes
Infrared light (viewed by special means)
Detect undersketching in art
Decipher charred documents
Differentiate inks (some absorb, while others reflect IR light)

8. Photographic techniques
Laser techniques
Discriminate between similar inks
Photographic techniques
UV, IR, and laser photography
Chromatography (thin layer or paper)
Ink from document is analyzed along with reference (suspected) ink samples
Inks are placed on thin layer of silica gel (or paper), which is then placed into a solvent.
The solvent moves up the gel or paper by capillary action, separating inks as it moves.

9. Chromatography is based on polarity
Chromatography is based on polarity. The gel or paper has a different polarity than the solvent.
Parts of the ink that are more “like” the gel or paper will not move, while those that are more “like” the solvent will travel up the chromatogram.
Samples that produce similar chromatograms are likely to be the same ink.