Marks and Impressions

Question 1

what are examples of body prints?

Answer 1

finger, lip, ear and foot

Question 2

what are examples of tool prints?

Answer 2

chisel, hammer, pliers

Question 3

what are examples of manufactured items that can leave prints?

Answer 3

tyres and shoes

Question 4

what other types of marks and impressions can be made?

Answer 4

weapons, bullets

Question 5

what is a positive impression?

Answer 5

An impression where material has been deposited

Question 6

what san example of a positive impression?

Answer 6

marks in blood

Question 7

what’s a negative impression?

Answer 7

material is removed

Question 8

what’s an example of negative impressions?

Answer 8

impressions found in dust

Question 9

what’s an example of indented impressions ?

Answer 9

where the surface is left deformed

Question 10

what is an example of indented impressions?

Answer 10

shoe prints in mud, or tool marks

Question 11

what is damaged based evidence?

Answer 11

identifying manufactured items

traits which enable individualisation

Question 12

what san example of damage based evidence?

Answer 12

tool marks, shoe prints and tyre prints

Question 13

what are non damage based evidence?

Answer 13

individual traits acquired naturally and every item is unique

Question 14

what’s an example of non damage based evidence?

Answer 14

fingerprints, lip prints and ear prints

Question 15

How do you identify impressions at a crime scene?

Answer 15

white light, UV, polarised light, monochromatic light, argon laser light, fluorescence imaging.

Question 16

what do you do after you identify impressions?

Answer 16

enhance them

Question 17

what is chemically enchanting impressions?

Answer 17

addition of reagents to alter the material, defining the mark

Question 18

what’s an example of chemical enchantment for blood marks or fingerprints ?

Answer 18

treating on paper with ninhydrin or DFO to reveal detail in purple

Question 19

what is physical enchancement?

Answer 19

physical adhesion of material to make the residue or lifting prints to enhance contrast

Question 20

what two factors have to be considered when retrieving impressions?

Answer 20

nature of surface and impression

Question 21

how do you lift fingerprints of a non porous surface?

Answer 21

Dust
cyanoacrylate fuming
wash with MoS2

Question 22

how to enhance iron coloration in soil?

Answer 22

treat soil with thiocynanate

Question 23

how to deal with chalky soil prints ?

Answer 23

use bromophenol blue to make the print turn blue

Question 24

what increases the contrast of oily marks?

Answer 24

iodine vapour

Question 25

what are 3 methods to lift impressions?

Answer 25

3D - plaster cast
in snow wax spray
2D dust impressions lift onto white gel film

Question 26

How do you do electrostatic lifting of a shoe impression in dust?

Answer 26

place metabolised black mylar sheet on print
charge to 15kV
imprint dust on sheet 
print on sheet with clear cover 
use oblique lighting

Question 27

after enchaining a print what should happen?

Answer 27

compare it

Question 28

what do you need to compare?

Answer 28

Using microscopy find individual traits eg:dents or chips.

Question 29

How can you classify shoe or tyre prints ?

Answer 29

size, manufacturer/pattern

Question 30

How can you individualise shoe or tyre prints?

Answer 30

systematic wear traits, cuts or scratches

Question 31

How do you interpret a shoes print ?

Answer 31

compare make by mark
classify by sole and heel pattern
individualise

Question 32

what do you need to identify a print ?

Answer 32

a sufficient number of individual traits

Question 33

what do you need to exclude a print?

Answer 33

key differences or conflicting traits

Question 34

what are the four stages you need to do to confirm who a print belongs to?

Answer 34

identify
enhance
compare
interpret