Writing instrument analysis
Writing instrument analysis involves the examination of documents to determine the specific tools used to create them, such as pens, pencils, or other marking devices. This analysis is significant in forensic investigations, particularly in cases involving handwritten documents that could provide crucial evidence, like ransom notes or forged signatures. Although the prevalence of handwritten communication has declined due to the rise of digital writing, the analysis remains an essential function of forensic science.
Various types of writing instruments are considered, from traditional options like fountain pens and graphite pencils to less common materials like crayons and spray paint. Techniques for identifying these instruments include visual inspections, microscopic examinations, and chemical analysis of inks. Investigators may compare original documents with known samples or analyze marks and indentations left by the writing instrument to discern its identity. Additionally, methods such as liquid chromatography can reveal ink compositions, aiding in tracing the specific writing instrument used. Overall, writing instrument analysis plays a critical role in linking documents to individuals and can serve as vital evidence in legal contexts.
Writing instrument analysis
DEFINITION: Examination of documents and writing instruments with the aim of determining which specific instruments were used to create the documents of interest.
SIGNIFICANCE: Handwritten documents often play important roles in criminal investigations and court cases. Through writing instrument analysis, forensic scientists can gather information about documents (such as wills, ransom notes, or threatening letters) that can help investigators link the documents to suspects.
Law-enforcement investigators sometimes encounter pieces of written that can potentially provide important information about individuals or crimes. In some instances, a document may be integral to the case, such as a ransom note or forged document. At other times, a scribbled note might be a clue to the identity of a criminal for whom investigators are searching. In these cases, any information that can be gathered about the documents and how they were produced can be helpful to investigators. Information linking a to a written document may also be used as evidence during a trial. Although the numbers of handwritten documents figuring prominently in law-enforcement investigations have diminished over time, as first the widespread adoption of typewriters and later the common use of computers and printers greatly reduced the frequency with which many people handwrite any documents, writing instrument analysis remains an important function of forensic science.
Types of Writing Instruments
Many different types of writing instruments may be used in the creation of a document. These include objects that are generally thought of as writing instruments, such as pens and pencils, as well as less commonly used instruments, such as crayons, spray paint, or lipstick. Anything that can be used to create a mark on a surface may be considered a writing instrument.
The most common writing instruments are mass-produced pens and pencils. For many years, the fountain pen was the most common writing instrument, but it was largely replaced in 1954, when the ballpoint pen was introduced. Fiber-tip or porous-point pens, roller-ball pens, and gel pens are also commonly used types of pens. Available pencil types include traditional graphite pencils, colored pencils, and mechanical pencils. Each pencil type is available in a wide range of lead sizes and softnesses. Each type of pen or pencil leaves specific, telltale signs of its identity on any document it is used to create.
Identification Techniques
The techniques used in identifying a writing instrument depend on the goal of the investigation and the availability of writing samples. In some cases, the goal of the investigator is to determine whether a particular document could have been created using a certain writing instrument. In such a case the writing instrument is generally available to create sample documents for comparison. The examiner then compares the original and sample documents, using the naked eye as well as the microscope, and conducts any relevant chemical tests.
If no suspected writing instrument has been identified, the examiner must try to determine as much information as possible using the available document. The first step in the attempt to determine what specific writing instrument was used is a visual inspection of the document. This inspection can usually provide information about the type of writing instrument used, such as whether the writing was created with a pen, pencil, highlighter, crayon, or other instrument.
The next step is to use a microscope to examine the document in more detail. Under the microscope, clues to the identity of the writing instrument that are not apparent to the naked eye become visible. For example, different types of writing instruments can be identified by the lines, marks, and indentations they leave in the writing surface. A pen that uses a ball to disperse ink leaves indentations from the ball in the paper that are visible under the microscope. A pen that does not use a ball, such as a fountain pen or a felt-tip pen, does not leave such indentations.
In some cases, an examiner is able to determine only the type of pen or other writing instrument that was used. In other cases, the examiner may be able to identify a specific writing instrument based on imperfections specific to that instrument. A pen tip that is bent or cracked, for example, will produce writing that is likely to show individual characteristics that can be identified by an expert.
The type of ink used can also help the examiner to determine the writing instrument that was used to create a given document. Inks may be tested in many different ways. Some tests involve wetting the sample with a solution and examining the way the ink spreads. An examiner may need to avoid such methods in some cases—for instance, if the goal of the examination is to validate a historic document or only a very small amount of sample is available to study—as they effectively destroy a section of the sample. Liquid chromatography can be used to identify the chemical compositions of inks. To perform the test, a small piece of is cut from the document and dissolved in a solvent. This method, which is a destructive technique, allows scientists to compare the ink to the US Secret Service's database of more than 9,500 inks, the International Ink Library.
Bibliography
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Brunelle, Richard L., and Kenneth R. Crawford. Advances in the Forensic Analysis and Dating of Writing Ink. Springfield, Ill.: Charles C Thomas, 2003.
Carlson, Brady. "The Secret Service Has an Ink Library to Foil Crimes (Cool Weird Awesome 1041)." Brady Carlson, 5 July 2023, www.bradycarlson.com/the-secret-service-has-an-ink-library-to-foil-crimes-cool-weird-awesome-1041/. Accessed 19 Aug. 2024.
Ellen, David. Scientific Examination of Documents: Methods and Techniques. 3d ed. Boca Raton, Fla.: CRC Press, 2006.
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Koppenhaver, Katherine Mainolfi. Forensic Document Examination: Principles and Practice. Totowa, N.J.: Humana Press, 2006.
Nickell, Joe. Pen, Ink, and Evidence: A Study of Writing and Writing Materials for the Penman, Collector, and Document Detective. New Castle, Del.: Oak Knoll Press, 2003.