Impressed Mark
Definition
Also called indented or compression mark. Tool is pressed perpendicularly into the softer surface and reproduces the contour of the tool's working face. Example: a hammer-face dent on a steel padlock shackle.
- Also called
- Indented mark or compression mark
- Formation method
- Tool pressed perpendicular to surface without sliding
- What it records
- The three-dimensional contour of the tool's working face
Common questions
What's the difference between an impressed mark and other tool marks?+
An impressed mark forms when a tool is pressed straight down into a soft surface without any sliding motion. Other tool marks like striations are made when the tool moves across the surface. Impressed marks show the full 3D shape of the tool's working face.
What kind of surfaces produce impressed marks?+
Softer surfaces are required for an impressed mark to form. A hammer striking a steel padlock shackle, for example, leaves a clear indented dent that records the shape of the hammer face.
Why are impressed marks useful in forensic investigations?+
Impressed marks capture a negative impression of the tool's surface pattern. This pattern can be compared to a suspect tool to determine if it was used in a crime, much like matching a fingerprint to a specific person.
Related terms
- Striated Mark
- Also called scratch, abrasion or scrape mark. Tool slides laterally across the surface and leaves parallel striations from microscopic imperfections on the...
- 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...
- AFTE Theory of Identification
- The Association of Firearm and Tool Mark Examiners' standard (1992, revised 2011) for reporting tool-mark comparison conclusions as Identification, Inconclusive, or Elimination...
- Asperity
- A microscopic surface protrusion on a tool's cutting edge; each asperity produces a groove in the substrate when the tool slides, contributing...
- Black-Box Validation
- A study design where examiners are given unknown questioned-vs-known pairs and asked to match or exclude without feedback, allowing error rates to...
- Class Characteristic
- A feature shared by an entire group of objects (every shoe of one model has the same sole tread; every tire of...
- Class Characteristics
- Features deliberately or systematically imparted to a group of items by design or manufacture, such as the calibre of a bullet, the...
- Combination Mark
- Both impressed and striated features in the same mark, typical of pry-bar and chisel attacks where the tool first bites into the...
- False-Positive Rate
- The proportion of authentic media files that a detection tool incorrectly classifies as manipulated or synthetic. Deepfake detectors and ELA tools both...
- Individual Characteristic
- A characteristic unique to a specific typewriter unit arising from manufacturing variation or service wear; used to identify or eliminate a specific...
- Individual Characteristics
- Surface features on a fired bullet or cartridge case that arise from random or unique events (tool wear, corrosion, service damage) and...
- Mikrosil
- Brand-name silicone polymer casting compound (also Microsil, AccuTrans) used to lift a fine-detail negative of a tool mark from the scene without...
Explained in these topics
- Tool Marks: Fundamentals, Striations and ImpressionsA tool mark produced by a tool pressed into a substrate without sliding; records the three-dimensional surface of the tool face as a negative impression.
- Tool Marks: Meaning, Types and ExaminationAlso called indented or compression mark. Tool is pressed perpendicularly into the softer surface and reproduces the contour of the tool's working face. Exampl...