2D Impression
Definition
A two-dimensional print on a hard, flat surface (tiled floor, polished cement, paper). Lifted with electrostatic dust lifter (ESLA), gel lifter, or photographed with oblique flash and powder.
- Mechanism
- Residue transfer: dust, blood, water, or paint
- Surface
- Hard surface, not deformed by contact
- Depth
- None, distinguishing it from a 3D impression
Common questions
How does a 2D impression differ from a 3D impression at the same scene?+
A 2D impression is a flat residue transfer with no depth, left on a hard non-deformable surface, while a 3D impression is a depth-bearing mould left in a soft medium such as soil or snow.
What documentation approach best suits a 2D impression?+
Photography with oblique lighting to reveal contrast, along with lifting by electrostatic or gel lifter where appropriate, since there is no depth to cast with dental stone.
Related terms
- 3D Impression
- An impression made in a deformable medium: soil, sand, snow, mud, soft asphalt. The sole or tread pushes into the medium and...
- Class Characteristic
- A feature shared by an entire group of objects (every shoe of one model has the same sole tread; every tire of...
- Individual Characteristic
- A characteristic unique to a specific typewriter unit arising from manufacturing variation or service wear; used to identify or eliminate a specific...
- Dental Stone
- A gypsum-based casting material harder and finer than plaster of Paris. Preferred for forensic 3-D casts because it captures detail at the...
- Drag Factor (μ)
- The effective coefficient of friction between the tyre and the road surface during a braking event. Used in the skid-mark speed formula....
- Gait Pattern
- The geometric and rhythmic signature of a person's walk. Captured as stride length, step length, cadence, foot angle and walking line. Used...
- Latent Impression
- An impression that is invisible or barely visible until developed or lifted. Dust impressions on dark floors and oblique-light-only impressions sit here.
- Patent Impression
- An impression that is visible to the naked eye without enhancement. A bloody shoeprint on white tile is patent.
- TWI
- Treadwear indicator. A small raised ridge moulded across the tread groove of every tire at 1.6 mm depth. When the surrounding tread...
Explained in these topics
- Footwear, Tyre and Footprint Impression EvidenceA residue-transfer impression on a hard surface: dust, blood, water or paint left when the shoe or tyre touched the floor without deforming it.
- Track Marks: Foot, Shoe, Tire, Skid Marks and Gait Pattern