Print classification
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Print Classification PowerPoint PPT Presentation


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Print Classification. Henry System- adopted in 1901, looked at ridge patterns on all 10 fingers, but only accommodated 100,000 sets of prints Primary Classification- divides all fingerprints in the world into 1024 categories Turns patterns into fractions

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Print Classification

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Print classification

Print Classification

  • Henry System- adopted in 1901, looked at ridge patterns on all 10 fingers, but only accommodated 100,000 sets of prints

  • Primary Classification- divides all fingerprints in the world into 1024 categories

    • Turns patterns into fractions

    • 1/1 means that all of the fingers have the same patterns

      • Approximately 25% of the population have 1/1 ratio

ACOS 2.2, 2.3


Uses of these systems

Uses of these systems

  • 10 finger system is only of use when the investigator has the names of the suspects on hand

  • Can be entered into a database and matched

ACOS 2.2, 2.3


Print classification

AFIS

  • Automated Fingerprint Identification System

  • Computer database of all fingerprints in the country

  • Monitored by the FBI

  • Allows for electronic comparison of a latent print to a known print

  • Helps to identify suspects

  • Reality of AFIS…Deanna Rice

ACOS 2.2, 2.3


Print classification

AFIS

  • The computer’s search determines the degree of correlation between the location and the relationship of minutiae of both the search and file prints

  • Prior to AFIS, police had to compare prints by hand to known suspects from previous cases or that had been printed already.

ACOS 2.2, 2.3


Latent prints

Latent Prints

  • Visible Prints - made by touching fingers to a surface after the ridges have been in contact with colored material such as blood, ink, or paint

  • Plastic Prints - left on soft material such as putty, wax, soap or dust

  • Latent Prints - transfer of body oils; can not be seen by the naked eye

ACOS 2.2, 2.3


Dusting for prints

Dusting for Prints

  • Powders are brushed onto a non-absorbent surface and will adhere to the oils left by the hand

  • Gray or Black powders are used to life most all prints

  • Specialized clear tape known as lifting tape is used to store the print safely

ACOS 2.2, 2.3


Fuming for prints

Fuming for Prints

  • Exposing a piece of evidence to fumes of super glue will expose prints

    • Either combine cotton cloth, sodium hydroxide and super glue

    • OR

    • Heat the super glue to allow evaporation

ACOS 2.2, 2.3


Preserve the print

Preserve the Print

  • Photograph the print

  • Cover with cellophane tape

  • Place on latent print recovery card

    • Card should be a contrasting color to the color of the powder used

ACOS 2.2, 2.3


Digital imaging

Digital Imaging

  • Computers can enhance and darken the print to make an easier image to read.

ACOS 2.2, 2.3


Print classification

ACOS 2.2, 2.3


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