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Handwriting Characteristics Comparison

Run the Handwriting Characteristics Comparison Fullscreen

About This MicroSim

When a document examiner is asked whether a signature or note is genuine, they compare a questioned sample against a known exemplar — writing the suspect is known to have produced. They do not look at the writing as a whole; they break it down into specific characteristics and compare each one.

This MicroSim puts the two samples side by side and lets you light up each of the six characteristics examiners rely on:

  • Line Quality — smooth, confident strokes vs. shaky tremor
  • Slant — the angle of the writing, measured in degrees
  • Spacing — the gaps between letters and words
  • Letter Formation — the shape of loops and connectors
  • Pen Lifts — where the pen leaves the paper
  • Baseline — how steadily the writing sits on its line

A toggle switches the questioned sample between a genuine match and a forgery, so you can see exactly how each characteristic changes when someone tries to copy another person's hand.

How to Use It

  1. Look at the Known Exemplar (left) and the Questioned Sample (right).
  2. Click any characteristic chip to highlight that feature on both samples. The exemplar is marked in blue; the questioned sample is marked green if it matches or red if it differs.
  3. Read the description and the MATCH / DIFFERS badge for the selected characteristic.
  4. Press Show Forged Sample to replace the questioned sample with a forgery. Watch the comparison summary change as characteristics begin to differ.
  5. Drag the Magnification slider to zoom in on both samples for a closer look.
  6. When Slant is selected, read the measured slant angle for each sample.

What You Can Learn

  • Identify the six characteristics document examiners use to compare handwriting.
  • Recognize how a forgery typically differs: tremor in the line, a changed slant, a drifting baseline, and extra pen lifts.
  • Read a comparison summary that tallies matching vs. differing characteristics.

You can embed this MicroSim on your own web page with this iframe:

<iframe src="https://dmccreary.github.io/forensic-science/sims/handwriting-comparison/main.html"
        width="100%" height="502" scrolling="no"></iframe>

Lesson Plan

Audience: High-school forensic science (grades 9–12) Time: 10–15 minutes Bloom level: Remember (L1) — identify.

Worked example. With the authentic sample showing, click through all six characteristics in order and confirm each one shows MATCH and a green highlight. Note that the summary reads 6 matching / 0 differing.

Guided questions:

  • Which characteristic is measured in degrees, and why is a number more useful to an examiner than "leans left"?
  • Press Show Forged Sample. Which characteristics now DIFFER, and which still MATCH? Why might a forger get spacing right but fail at line quality?
  • What are pen lifts, and why does copying someone else's writing tend to add extra ones?

Extension. Have students collect two signatures from a classmate on different days and list which of the six characteristics stay consistent — the ones that are most stable are the hardest to forge.

References

Specification

This MicroSim was generated from a specification in Chapter 14: Document Examination and Forgery Detection.

Design note: the handwriting is a procedurally generated stylized cursive stroke, not real letters — it is a schematic stand-in that lets each characteristic (slant, tremor, baseline, spacing, pen lifts) be controlled and highlighted clearly. The authentic and forged samples use fixed parameters, so the comparison is illustrative rather than a measurement of real handwriting.