FORENSIC SCIENCEUnit 2B Day ThreePrints DUE TODAY: My Prints- front and back ( finish back using chart in lab area) Investigation 7- Individualization of prints
Getting started 9-16 • What is “minutiae”? • What minutiae can you detect on the print to the right? Name at least 3
Visible Prints • Touching a surface after ridges are in contact with colored material such as ink, blood, paint, grease, etc.
Plastic Prints • Ridge impressions left in soft material such as putty, wax, soap or dust
Latent Prints Latent fingerprints are those that are not visible to the naked eye. These prints consist only of the natural secretions of human skin and require treatment to cause them to become visible.
Primary Identification Numbers Fingers are numbers 1 through 10 with the thumb on the right hand and continuing through with the thumb on left hand. Each finger is then given a point value as seen in the chart below. 1. right 2. right 3. right 4. right 5. right thumb index middle ring little 16 16 8 8 4 6. left 7. left 8. left 9. left 10. left thumb index middle ring little 4 2 2 1 1
Primary ID continued • The presence or absence of the whorl pattern is the basis for the Primary • If a whorl pattern is found on any finger of the first pair it gets a 16 • Second pair gets an 8 • Third pair gets a 4 • Fourth pair gets a 2 • Fifth pair gets a 1 • If there is an arch or loop =0 • Add 1 to the numerator and denominator
Today’s assignments: • SET UP Short-term versus Long-term prints (ON TABLE 1) • P.I. Practice- on table1
Getting Started: • Reviewing PI number method… again
Lifting Latent Prints Developing causes the print to stand out against its background. • Powders—Best with hard surfaces . Choose a color to contrast the background. • Use as LITTLE powder as possible. Shake off excess above trashcan or sink • Gently place powder on print • Then use tape to “pick up” powder- Don’t rub tape into print!!
Today’s agenda: • Due Today: PI Practice- make sure you check it before turning in • Finish up Short term/Long term observations • Fingerprint review- on TABLE 4 • Latent prints with powders- on TABLE 4