1. Making Good Impressions

2. Impression Evidence Imprints Indentations Striations
There are three different types of impression evidence:
Imprints
Indentations
Striations

3. Imprints
Imprints are made when material from one area is transferred to another. Imprints are two dimensional….(l x w)

4. Indentations
Indentations are made when the object pushes into material which is softer than the object itself. This creates a three-dimensional print... (l x w x d)

5. Striations
Striations are related to indented impressions in that the impression leaves a three-dimensional image. There is one element that is added; the object is in motion. For example, a crowbar prying a vending machine open will not only leave a tool mark but will also leave the streaks of motion indented as well. Striations really tell a story.

6. Shoeprints, Tires and Tools

7. What can footprints tell you?
Watch Where You Step!
What can footprints tell you?
Your range of height
Your walking style
Whether you are standing or running
Points of entrance/exit into and out of a crime scene
The path to the weapon
Linkage

8. The Three Basic Shoeprints…
Patent – tracking through a substance like paint or blood
Plastic – walking through mud or snow indenting the shoeprint along the way
Latent – transferring thin layers of accumulated grime to a hard surface, piece of paper, wooden floors, etc…. Invisible to the naked eye
Sound Familiar?

9. Class vs. Individual Characteristics
Shoeprints are often considered class evidence because they identify only the manufacturer and size of the shoe narrowing the search for a suspect but not pinpointing the individual.

10. How do you make your shoes ‘your own’?
Wear patterns
Cuts
Nicks
Scratches
Gouges
Stones
You know… shoe stuff

11. What else can we learn about you?
Gait patterns
Walking style
Length of stride
Stance
Pigeon-toed
Slew-footed
Limp
Height

12. To cast or To mold, that is the question
Cast – A reproduction of an object that made an impression… a positive replica
Mold – A reproduction of the impression made by an object… a negative replica

13. Casting a Footprint Spray a footprint/ shoeprint with a fixative
Mix up water and dental stone (or plaster if it is easier) in a gallon Ziplock bag
Gently pour the plaster on a stick to ease the plaster on to the indentation.

14. Casting a Footprint
Let the plaster set for about minutes
Etch your initials, case number, and date into the outer sole
You may be able to take your cast out of the substrate at this point
Let set completely for 24 hours
You will get more detailed information in lab but this is the basic idea.