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Other Clues on the Document

Document Examiners

According to Emily J. Will, a Board Certified Forensic Document Examiner (D-BFDE) specializing in handwriting identification and suspect documents, "the most important tool a document examiner has is his or her own vision."

While equipment may enable the examiner to see things, it is knowledge and experience that allow the examiner to interpret these findings correctly. Document examiners must typically complete a two-year, full-time training program. They may be accredited by the American Board of Forensic Document Examiners (ABFDE) or the American Society of Questioned Document Examiners (ASQDE).

What They Look For

As discussed in the previous lesson, document examiners analyze handwriting to determine the author of the document. However, there are many other aspects of the document that examiners look at:

  • Erasures - removal of a portion of the original document
  • Alterations - modifications made to a document by physical or chemical means
  • Obliterations - purposefully covering an area of the document, usually with other writing
  • Indentations - depressions on the surface of document created by the pressure of writing, often found on paper that was under the original document

Examples of Modifications

Check out the following examples from Forensic Science Simplified:

First, open Why and When is Forensic Document Examination Used? and scroll to the section on "Fraudulent Checks" to see how infrared radiation and an Electrostatic Detection Device (EDD) can be used to detect alterations and indentations.

From that same site, open How It's Done and scroll to the section "Detecting alterations, obliterations, erasures and page substitutions". Take a look at another example of how infrared radiation can be used to detect an obliteration.

Knowledge Check #1

Although the original note was removed, this notebook found at the suspect's home maintains evidence of the message.

A notebook with a message imprinted on it, but ink is not physically on the paper.
Image courtesy of Georgia Courtesy of the Georgia Bureau of Investigation

This is an example of blank_________.

  1. erasures
  2. alterations
  3. indentations
  4. obliterations

Answer: c. indentations

Tools Used

Examiners use a variety of tools to see more than is available to the naked eye.

  • Magnifiers - Magnification of 4x, 7x or even 10x the normal size can allow examiners to see details of the writing.
  • Microscopes - Microscopes allow for even greater magnification. However, magnification over 50x is rarely used by examiners. Doing so creates a very narrow view of the writing.
  • Infrared and Ultraviolet Light - Wavelengths longer (infrared) and shorter (ultraviolet) than what is visible to the human eye, these light sources reveal differences in inks that may otherwise appear similar, allow examiners to see beyond an obliteration, and reveal hidden security features.
    diagram of the visible spectrum of light by wavelengths in nanometers (nm) from 700 nm to 400 nm. On the visible spectrum, red has a wavelength of 700 nm, orange has a wavelenght of 600 nm, yellow 580 nm, green 550 nm, blue 475 nm, indigo 450 nm, and violet 400 nm. Infrared radiation (IR) is to the left of the visible light with larger wavelengths than visible light (more than 700 nm), and ultraviolet light (UV) is to the right of the visible light spectrum with shorter wavelengths than 400 nm.


  • Electrostatic Detection Device - Detects indented writing by transferring an electrostatic charge to a document and covering it with a special powder that is drawn into the indentations.

Non-Destructive Methods vs. Destructive

The methods listed above are non-destructive and can be carried out by all certified document examiners. We will now discuss examinations that may be destructive to the evidence and require more specialized investigators such as a paper or ink analysts.

Paper Analysis

Through paper analysis, investigators can determine a lot of historical and physical evidence from paper-based objects like documents, photographs, art prints, books, etc.

From standard optical magnification to complex molecular spectroscopy, there are many analytical tools that investigators use to determine the properties and characteristics of paper.

  • Qualitative analysis can identify what materials are in the paper, such as fiber and ink.
  • Quantitative analysis measures how much of those materials are present.
  • Chemical analysis evaluates things like composition and pH.
  • Physical analysis measures gloss, strength, color.
  • Organic analysis detects carbon-based traces of plants and organisms.
  • Inorganic analysis identifies mineral evidence in pigment and ink.

Each kind of analysis provides factual information like the condition, age, and/or origins of an artifact ("Paper").

Analysis Questions

How do investigators know what kind of analysis to perform? According to PBS History Detectives, that depends on things like:

  • Investigator objectives -- Is the goal authentication, preservation, or just personal curiosity?
  • The value of the paper/document -- What is the relative value of the item historically, legally, or personally?
  • The balance of priorities -- If destructive testing methods are used, does the information gained from the testing offset any loss of the material?

The Vinland Map

The Vinland Map claims to be the first recording of the North American coastline (noted as the "Island of Vinland" on map), years before Columbus's first voyage to the Americas. It's thought to be a 15th century map based on a 13th century original, but its authenticity has been under speculation since it was purchased by Yale University in 1958.

The Vinland Map. The map is old and worn on the edges. Part of the map has been cut off at the bottom.
The Vinland Map claims to be the first recording of the North American coastline, years before Columbus. Courtesy of Yale University Press | Public domain. See larger version of the Vinland Map here.

In 2002, a 3-inch section of parchment from the bottom of the map was removed and analyzed by radiocarbon dating (which is a destructive method for identifying the age of a substance's organic material). Scientists from the University of Arizona, the U.S. Department of Energy's Brookhaven National Laboratory, and the Smithsonian Institution dated the map to 1434 A.D. plus or minus 11 years, almost 60 years before Columbus!

However, ink analysis of the map disagrees with this dating, leading to controversy over whether this map is a true historical document or a very convincing 20th century forgery.

Ink Analysis

There are both non-destructive and destructive ways to conduct ink analysis. Optical examination (non-destructive) can reveal if the same ink was used throughout the document or if ink on two different documents may have a common origin. It cannot, however, reveal the individual components of the ink.

Did You Know? The U.S. Secret Service maintains the International Ink Library, which contains data on over 15,000 inks, including printer ink and inks manufactured as early as 1920.

Ink Chromatography

To reveal the individual components of the ink, ink chromatography is used. This technique is built upon the molecular separation of a substance. Ink is made of different molecules and these molecules will migrate and separate upwards when they are applied to a highly absorbent material like filter paper.

Each molecule's relative attraction to the solvent will determine how far up the filter paper they will move. Once they have stopped moving the molecules will deposit themselves onto the filter paper and will create what is called a chromatographic pattern.

Chromatograph of a brown permanent pen. "Thin layer chromatography of stabilo OHPen brown permanent ink on silica gel 60 F254 with ethanol:water=80:20 (v/v)" by Wannowius is licensed under CC BY-SA 3.0.

Secret Service International Ink Library

Do you know that not all Secret Service members wear black suits and earpieces? The Secret Service has the largest ink library in the world including over 15,000 inks from pens, bottled ink, and printer cartridges.

Scientists at the Secret Service include people who specialize in handwriting analysis to investigate threat letters or ransom notes and fraudulent items like IDs, traveler's checks, credit cards. These document analysts include chemists who compare ink used in a threatening letter to inks in the collection, among other forensic investigation activities.

Most of the inks in International Ink Library are samples of black ink. Why would you need that many different kinds of black ink? Well, black inks aren't just black. They're actually a collection of different color components -- blues, reds, yellows, greens, etc. Through chromatography, chemists can sequence the ink to determine the exact breakdown of color.

Most manufacturers add a unique dye to their inks each year so every year the library must be updated. This also helps to date the "age" of the ink/pen being used. The International Ink Library contains over six thousand different types of chromatographic patterns for comparison purposes.

Counterfeit Currency

The most counterfeited bank note in the US is the 20 dollar bill and it's printed with inkjet, meaning someone takes their simple at-home printer and uses it to print money. The document analysts at the Secret Service can compare the counterfeit currency to any printers found at the scene of the crime and help make a match.

Examples

To learn more, check out the article Cabinet of Curiosities: 15,000 Ink Samples at Secret Service from the Associated Press. Be sure to look at the images to see what the ink collection looks like, including their collection of scribble sheets for visual comparisons!

Knowledge Check #2

Which currency is most often counterfeited in the United States?

  1. $10 bills
  2. $20 bills
  3. $50 bills
  4. $100 bills

Answer: b. $20 bills. $20 bills are the most often counterfeited bill in the United States.

Knowledge Check #3

True or False: Black inks are typically made of several different colors.

  1. True
  2. False

Answer: a. True. Black inks are typically made of several different colors mixed together.

Credits

"How the Secret Service Uses Ink to Solve Crimes." Great Big Story, 30 Apr. 2019, https://youtu.be/kCKM_ICjDtc.

"Paper Analysis." History Detectives, Public Broadcasting Service (PBS), 2014, www.pbs.org/opb/historydetectives/technique/paper-analysis/.

Will, Emily J. "Lab Tour: Introduction." Emily J. Will, D-BFDE, 2015, www.qdewill.com/labtour.html.