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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

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Print Classification

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  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. Digital Imaging • Computers can enhance and darken the print to make an easier image to read. ACOS 2.2, 2.3

  10. ACOS 2.2, 2.3

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