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Forensics :: Footwear Impressions
| Footwear impressions are a valuable form of physical evidence. Information from footwear impressions can provide an important link between the criminal and the crime scene. It can also assist in identifying a suspect. When an individual commits a crime, footwear impressions are often left at the scene. These impressions can be located, examined and photographed for evidence. All crime scenes should be approached with the expectation that they contain footwear impressions. However, these impressions are easily overlooked and sometimes destroyed while other evidence is being gathered. It is, therefore, important that footwear impressions be considered in the very early stages of the investigation. |
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Footwear Impressions |
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| Two dimensional footwear impressions are the results of a transfer of trace materials; thus giving a visual image of the residue on a surface such as synthetic or wood flooring, paper, glass or plastic. Because of the trace quantity of residue or the lack of contrast with the substrate material, it is often difficult to see footwear impressions in standard lighting conditions.
The detection of latent or faint footwear impressions demands oblique lighting. Grazing light is reflected off the residue, giving a contrast-enhanced image. It is most effective when photographing footwear impressions. Close-up photographs taken at the crime scene, as well as quality photographs of impressions on adhesive lifting materials or on films for electrostatic lifting, show best results when using oblique light.
Appropriate light sources should provide a bright and homogeneous shadow-free illumination when positioned at a low angle of incidence relative to the surface being examined.
The VOLPI cold light source equipped with a line converter (light line) is the most suitable lighting for the detection and examination of footwear impressions. Variable light intensity and variable focusing lens, provide the necessary homogeneous and oblique light for the non-destructive enhancement of faint and latent evidence.
Other forensic applications:
- Detection of general trace evidence
- Examination of stamped or embossed impressions
- Detection of indented writings
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