Examination of Questioned Documents

Introduction.

Questioned document examination  involves a great many areas of expertise.  Included under questioned document examination are the following disciplines, a few of which I will hit on this this section:  handwriting, typewriting, photocopying and computer printers, forgery, paper and inks, writing instruments, computer disks, gambling machinery, stamps (as in the rubber pad kind) and the dating of documents.  

Handwriting Analysis.

Graphology, the study of handwriting to determine one's personality traits, is not handwriting analysis.  It's not even considered a science; more like a parlor trick.  True handwriting analysis involves painstaking examination of the design, shape and structure of handwriting to determine authorship of a given handwriting sample.   The basic principle underlying handwriting analysis is that no two people write the exact same thing the exact same way.    Every person develops unique peculiarities and characteristics in their handwriting.  

Handwriting analysis looks at letter formations, connecting strokes between the letters, upstrokes, retraces, down strokes, spacing, baseline, curves, size, distortions, hesitations and a number of other characteristics of handwriting.  By examining these details and variations in a questioned sample and comparing them to a sample of known authorship, a determination can be made as the whether or not the authorship is genuine. 

 

Try this at home:  Sign your name as you would sign a credit card receipt or some other official document.  Have several friends do the same.  Now trade.  Take a few minutes and try to forge each others signatures.  Even more difficult, write a paragraph in your natural handwriting, swap those and try to forge them.

Typewriting.

First, a review of individual characteristics.  This topic is first discussed in the firearms page.  If you haven't been there, you might want to go back.  Individual characteristics are either inherent in the machining process of a manufactured item, or come about through the wear and tear in the use of an object.  It is these individual characteristics that allow for the identification of an object to the exclusion of all others of its general type.  As with typewriters, all typewriters of a particular make and model are pretty much the same but, through use, the develop defects that translate to paper when the machine is used.  These defects on the typed page can be matched back to the typewriter that was used to create it.  
These defects in the type face are revealed in a number of ways.  If the type bar is bent (the bar on which the letter element is attached and hammered down to the page) the letter is misaligned or 'off its feet.'  Misalignments can also cause non-printing areas of a specific letter, such as losing the loop on the bottom of a 'g.'  The letter can be displaced horizontally or vertically.  Little clumps of plastic can adhere to the type key during manufacture and are made permanent by the coating process.  This defect is called 'flashing.'  As wear and tear increases, the defects become more exaggerated.

Just looking at the type style, or font, the spacing (horizontal and vertical) and type size allows for determining the make and model of the typewriter.

Ribbons are a major evidentiary component.  It is possible to read a ribbon to see what it has been used to type.

 

Photocopiers and Laser Printers.

Photocopiers and laser printers use the same type of process to print a page.  With a photocopier, the original document is placed on the glass platen.  The document is then exposed by use of reflected light to a drum that is covered with a photosensitive material.  The image of that document exists on the drum as an invisible positive photoelectric charge.  Negatively charged toner, the messy black powdery stuff, is drizzled onto the drum, where it sticks to only the positively charged areas (remember magnets?  Opposite charges attract, same charges repel), to create a visible image.  Paper, with a positive charge, passes the drum, causing the negatively charged toner to transfer to the paper.  The toner is then heat sealed to the paper, creating the printed copy.  With a laser printer, the image of the original document (held by the computer in its memory) is written to the photosensitive drum by use of a laser.

 

There are many ways to match a page back to a photocopier or laser printer.  Since, as shown above, the processes are similar, the methods used  to match a page back to its origin, printer or copier, will also be similar.

The paper itself can yield many clues.  Look for marks from the belts, pinchers, rollers and gears that physically move the paper through a machine.  These examinations would be similar to toolmark examinations, discussed in the Firearms page.   

Toner can have unique characteristics in its chemical composition.  Also, look at how the tone was placed on and fused to the paper.  Toner may clump up on the drum, tranfering blobs of toner at a time to the printed page.  

Marks on the optics (glass platen, lenses, mirrors) used to transfer or create an image on paper might contain unique defects (such as scratches) that will render anomalous markings on the printed page.

 

About the Author.

The author is a corporate/legal/forensic investigator and holds a B.A. in Criminal Justice   and an M.A. in Forensic Science, specializing in counter-terrorism and questioned document examination.  He has worked with local police, at the federal level, and at the international level specializing in investigative work and executive protection.  The author currenlty works in the private sector as Manager of Investigations for a corporate investigative firm.

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