There are three types of fingerprints that can be found: latent, patent, and plastic. This type of fingerprint is invisible to the naked eye and requires additional processing in order to be seen.
This processing can include basic powder techniques or the use of chemicals. Patent fingerprints can be made by blood, grease, ink, or dirt. This type of fingerprint is easily visible to the human eye. Plastic fingerprints are three-dimensional impressions and can be made by pressing your fingers in fresh paint, wax, soap, or tar. Like patent fingerprints, plastic fingerprints are easily seen by the human eye and do not require additional processing for visibility purposes.
Surface Characteristics and Collection Methods Characteristics of the surface in which the print is found are important in deciding which collection methods should be employed on scene. The general characteristics of the surface are: porous, non-porous smooth and non-porous rough. The distinction between porous and non-porous surfaces is their ability to absorb liquids.
Liquids sink in when dropped onto a porous surface, while they sit on top of a non-porous surface. Porous surfaces include paper, cardboard, and untreated wood. Non-porous smooth surfaces include varnished or painted surfaces, plastics, and glass.
Non-porous rough surfaces include vinyl, leather, and other textured surfaces. For porous surfaces, scientists sprinkle chemicals such as ninhydrin over the prints and then take photographs of the developing fingerprints.
For non-porous smooth surfaces, experts use powder-and-brush techniques, followed by lifting tape. For rough surfaces, the same powdering process is used, but instead of using regular lifting tape for these prints, scientists use something that will get into the grooves of the surface such as a gel-lifter or Mikrosil a silicone casting material. Analysis of Collected Prints Once a print is collected, analysis can begin.
Skip to main content. Login Register. Page DOI: American Scientist Comment Policy Stay on topic. Be respectful. A scanner is then used to save the data electronically in the appropriate format. The latest version v. Both sets of guidelines and the related file package can be downloaded from our GitHub platform.
Any feedback, questions or problems can be submitted via the Issues page. Along with DNA, fingerprints can play an important role in identifying victims following natural or manmade disasters such as an earthquake or bombing. This is important not only for the police investigating the incident, but also for the families concerned. We also provide training to police in our member countries, to ensure that frontline officers have the knowledge and skills necessary to assess, preserve and share evidence in line with best practices.
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