Forensic Handwriting Identification Facts and Fundamentals
Each person has distinctive handwriting traits which distinguish themselves from every other writer. Forensic handwriting identification principles help establish a baseline for analysis. There are two basic principles that are taught in document examination and they are:
- No two people write exactly alike in an extended writing sample.
- No one can duplicate anything that they have written.
Writing is a learned habit practiced for many years. Between the ages of 18 and 24 most individuals reach graphic maturity. Graphic maturity is when an individual no longer concentrates on how to write letter forms when writing. They focus on content, not letter formation.
For the most part, writing is habitual. It is your brain writing. Your brain tells the muscles in your arm, wrist and fingers to move in specific combinations of contracting and expanding in order to complete specific letters. There are a lot of elements that go into writing. Some of the characteristics that handwriting experts look at are line quality, pressure patterns, slant, proportions of letters, methods of construction, connecting strokes, and natural variation to name a few. These characteristics and others not listed contribute to something called a master pattern.
The reason why you will encounter document examiners requesting 20-25 known, authentic samples of writing is because they need to establish a range of natural variation within the master pattern and all of the characteristics of writing need to be compared.
sample of natural variation used for handwriting identification