# "Incriminating Marks: Imprints vs Impressions"

In this first part of the series, we examine the differences between imprints and impressions as they relate to forensic evidence. While both types of marks can be left at

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## About "Incriminating Marks: Imprints vs Impressions"

PowerPoint presentation about '"Incriminating Marks: Imprints vs Impressions"'. This presentation describes the topic on In this first part of the series, we examine the differences between imprints and impressions as they relate to forensic evidence. While both types of marks can be left at. The key topics included in this slideshow are . Download this presentation absolutely free.

## Presentation Transcript

Slide1Incriminating MarksPart 1

Slide2What are we looking at? Imprints  vs.  Impressions  Imprints  vs.  Impressions  Very  real  differences  Very  real  differences  Determining  the  difference  can  determine how  the  evidence  is  collected  Determining  the  difference  can  determine how  the  evidence  is  collected

Slide3Imprints Is  a  two-dimensional  pattern  on  a  hard surface  Is  a  two-dimensional  pattern  on  a  hard surface  Examples:  Examples:

Slide4Impressions Is  a  three-dimensional  indentation  or  pattern  Is  a  three-dimensional  indentation  or  pattern  Formed  when  an  object  presses  into  a softer  surface.  Formed  when  an  object  presses  into  a softer  surface.  Examples:  Examples:

Slide5Information Specific toShoeprints  Can  be  impressed  or  “ visible ”  Can  be  impressed  or  “ visible ”  Many  Different  Ways  to  collect  this evidence  Many  Different  Ways  to  collect  this evidence  Many  Different  Factors  involved  in  the analysis  of  this  evidence  Many  Different  Factors  involved  in  the analysis  of  this  evidence

Slide6Types of Shoeprints Visible  (Imprint)  Visible  (Imprint)  Stepped  into  something,  then  onto something  Stepped  into  something,  then  onto something  Impressed  (Impression)  Impressed  (Impression)  Stepped  into  something  Stepped  into  something

Slide7How to collect ImprintEvidence  Many  different  ways  to  collect,  based  on  the type  of  shoeprint  it  is  Many  different  ways  to  collect,  based  on  the type  of  shoeprint  it  is  Electrostatic  Lifting  Electrostatic  Lifting  Gelatin  and  Adhesive  tape  lifting  Gelatin  and  Adhesive  tape  lifting  Photography  Photography  Powdering  and  Imprints  Powdering  and  Imprints  Chemical  Enhancements  Chemical  Enhancements

Slide8Electrostatic Lifting Used  for  lifting  “ Visible ”   Shoeprints  Used  for  lifting  “ Visible ”   Shoeprints  Uses  Electricity  to  place  a  charge  on  the  particles  Uses  Electricity  to  place  a  charge  on  the  particles  Used  on  many  different  surfaces:  almost everything  Used  on  many  different  surfaces:  almost everything Video  of  Lifting Video  of  Lifting

Slide9Chemical Enhancement Tests  on  the  residues  found  within  the imprints  Tests  on  the  residues  found  within  the imprints  Examples  of  what  can  be  found  is:  Examples  of  what  can  be  found  is:

Slide10How to collect ImpressionEvidence  Photograph  Photograph  Casting  Casting  Is  done  differently  depending  on  the location  of  the  impression  Is  done  differently  depending  on  the location  of  the  impression How  to  make  a  cast How  to  make  a  cast

Slide11 Comparing Evidence Most  important    FIND  THE  ORIGINAL OBJECT  Most  important    FIND  THE  ORIGINAL OBJECT  This  is  the  “ known  standard ”  This  is  the  “ known  standard ”  Database  of  shoe  and  Tire  treads   –  used  to exist!  Law  enforcement  only  has  it  now.  Database  of  shoe  and  Tire  treads   –  used  to exist!  Law  enforcement  only  has  it  now.

Slide12Analysis of Evidence 3  Major  steps  to  examining  evidence  3  Major  steps  to  examining  evidence  Determine  what  made  the  prints  (class)  Determine  what  made  the  prints  (class)  Determine  the  (individual)  characteristics of  the  print  Determine  the  (individual)  characteristics of  the  print  Comparing  to  Known  Standards  Comparing  to  Known  Standards