Individual Characteristic
Definition
A characteristic unique to a specific typewriter unit arising from manufacturing variation or service wear; used to identify or eliminate a specific machine as the source of a questioned document.
- Source of uniqueness
- Random wear, damage, manufacturing variation, and personal habits.
- Found in
- Fingerprints, DNA profiles, tool marks, handwriting, footwear, tires, and typewriters.
- Role in comparison
- The actually-discriminating set that proves one specific source, not one of many possible sources.
Common questions
What is an individual characteristic?+
A feature that is unique to one specific source. It could be a fingerprint ridge pattern, the wear marks on a particular tool, a cut on a specific shoe, or a handwriting habit of one writer. Individual characteristics are what allow forensic examiners to say 'this came from that person' or 'this came from that object,' not just 'it could be one of many.'
Why do individual characteristics carry more weight in forensic analysis than class characteristics?+
Class characteristics narrow down a group. Individual characteristics identify one specific source. In tool marks, footwear impressions, handwriting, and even DNA profiles, the individual features are what actually discriminate between suspects and sources. A match on individual characteristics is what makes identification possible.
Where do individual characteristics come from?+
They arise through random wear, damage, and variation during manufacturing or use. A tool develops nicks and chips. A shoe picks up cuts and embedded stones. A writer develops personal motor habits that depart from the standard template. These random changes are what make each source distinct and impossible to perfectly duplicate.
Related terms
- Class Characteristic
- A feature shared by an entire group of objects (every shoe of one model has the same sole tread; every tire of...
- Line Quality
- The overall fluency, rhythm and pressure variation of a stroke. Genuine writing has smooth, rhythmic, pressure-modulated lines; forgeries show tremor, blunt starts...
- 2-D Impression
- A two-dimensional print on a hard, flat surface (tiled floor, polished cement, paper). Lifted with electrostatic dust lifter (ESLA), gel lifter, or...
- 2D Impression
- A residue-transfer impression on a hard surface: dust, blood, water or paint left when the shoe or tyre touched the floor without...
- 3-D Impression
- A three-dimensional impression in a soft medium (mud, sand, soil, snow). Photographed in situ with scale and oblique light, then cast with...
- 3D Impression
- An impression made in a deformable medium: soil, sand, snow, mud, soft asphalt. The sole or tread pushes into the medium and...
- AFTE Range of Conclusions
- Association of Firearm and Tool Mark Examiners standard scale: Identification, Inconclusive (A, B, C), Elimination, Unsuitable for examination. The same scale used...
- Allograph
- The abstract mental representation of a letter form. Different people may share the same allograph (from copybook training) but execute it with...
- ASTM E2290
- ASTM International standard guide for examination of handwritten items; lists the 21 discriminating elements that the examiner reports on.
- Ballistic Execution
- The phase of a motor stroke that runs to completion without real-time feedback correction. Ballistic strokes are the most consistent within a...
- Baseline
- The imaginary line on which letters rest; can be straight, ascending, descending, convex, concave or undulating.
- Carbon-Film Ribbon
- A single-strike typewriter ribbon with a carbon coating that transfers completely to paper on impact, enabling high-quality impressions; the used ribbon retains...
Explained in these topics
- Footwear, Tyre and Footprint Impression EvidenceRandom wear and damage acquired in use: cuts, embedded stones, sole scuffs, uneven wear, repair marks. The basis for identification of a specific shoe or tyre.
- Handwriting Characteristics, Factors and Standard SamplesA feature that emerges as the writer drifts from the copy-book; it is the writer's personal habit and carries identification value.
- Handwriting Individuality and Class vs Individual CharacteristicsA feature that departs from or elaborates on the class template in a way specific to a particular writer's motor programme; the features that carry identificat...
- Physical Evidence: Types, Classification, Probative ValueA property unique to one source (a specific fingerprint ridge pattern, an STR DNA profile, a tool's wear marks). Identifies one person, one weapon, one object.
- Tool Marks: Meaning, Types and ExaminationRandom nicks, chips, accumulated wear and damage that are unique to one specific tool. The basis for an identification match.
- Track Marks: Foot, Shoe, Tire, Skid Marks and Gait PatternA randomly acquired feature unique to one specific shoe, foot or tire (a cut, a gouge, a wear pattern, an embedded gravel chip). The actually-discriminating se...
- Typewriter Examination: Mechanical, Electric and ElectronicA characteristic unique to a specific typewriter unit arising from manufacturing variation or service wear; used to identify or eliminate a specific machine as...