Latent Print Development

Question 1

what are the diff types of prints

Answer 1

• visible/ patent
• latent/ invisible
• plastic/ moulded

Question 2

all types of prints are commonly associated with what term

Answer 2

latent print

Question 3

what are patent/visible prints

Answer 3

• fingerprints visible to the unaided eye
• can use other things to enhance the print

Question 4

how do you search for patent/visible prints

Answer 4

use of light sources

Question 5

what are latent/invisible prints

Answer 5

fingerprints not seen until developed by physical or chemical process

Question 6

how are patent/visible prints preserved

Answer 6

photography

Question 7

how are latent/invisible prints preserved

Answer 7

• photos
• possibly tape on lift card

Question 8

what are plastic/moulded prints

Answer 8

• 3D impression of a print
• often visible to the unaided eye

Question 9

how are plastic/moulded prints preserved

Answer 9

• photography
• casting materials

Question 10

true/false porous substrates are absorbent

Answer 10

true

Question 11

true/false nonporous substrates are absorbent

Answer 11

false

Question 12

true/false fingerprints on porous substrates are durable

Answer 12

true

Question 13

true/false fingerprints on nonporous substrates are durable

Answer 13

false

Question 14

how do fingerprints on porous substrates look

Answer 14

imbedded in substrate

Question 15

how do fingerprints on nonporous substrates look

Answer 15

polished/shinny in appearance

Question 16

what are the best techniques for porous surfaces

Answer 16

AA

Question 17

what are the best techniques for nonporous surfaces

Answer 17

• cyanoacrylate (CA)
• fluorescent dyes
• powders
• ALS or FLS

Question 18

what approach is taken w latent print development

Answer 18

systematic approach

Question 19

true/false multiple techniques can be done after each other to develop

Answer 19

true

Question 20

what will dictate the steps you take

Answer 20

• trial and error
• experience

Question 21

what factors influence the choice of technique

Answer 21

• matrix
• surface
• texture
• condition of substrate sticky, dirty
• environmental conditions
• consequence of destructive processing methods
• subsequent forensic exams DNA
• sequence of fingerprinting processes
• seriousness of crime

Question 22

how is ninhydrin applied

Answer 22

• dipped or sprayed on
• then heat and humidity (60-70%) applied

Question 23

what does ninhydrin react w

Answer 23

• AA
• proteins in eccrine components

Question 24

what colour does ninhydrin give off

Answer 24

• magenta to deep purple
• “ruhemann’s purple”

Question 25

how is indanedione applied

Answer 25

items dipped and baked

Question 26

what does indanedione react w

Answer 26

AA

Question 27

what colour does indanedione give off

Answer 27

- faint pink colour - **fluoresces yellow** w ALS - *strong colour and fluorescence*

Question 28

**true/false** indanedione can be used before ninhydrin

Answer 28

- false - can be used *after* - but then he later said to do indanedione first so I’m really confused id look it up

Question 29

how is DFO applied

Answer 29

- dipped or sprayed on - dried and placed in oven

Question 30

what does DFO react with

Answer 30

AA

Question 31

what colour does DFO give off

Answer 31

- pink or fluorescent yellow - use ALS - photo w orange/red filter

Question 32

how are physical developers applied

Answer 32

- *lengthy process w multiple steps* - dipped/ immersed - pre-wash, immerse, 3 post-wash baths - *think of how fragile wet paper is*

Question 33

what do physical developers react w

Answer 33

- lipids - fats - oils - waxes

Question 34

what colour do physical developers give off

Answer 34

grey

Question 35

what does ALS stand for

Answer 35

alternate light source

Question 36

what can poli-lights be

Answer 36

- handheld - portable unit

Question 37

**true/false** poli-lights have one wavelength

Answer 37

- FALSE - multiple

Question 38

**true/false** portable lasers have one wavelength

Answer 38

true

Question 39

**true/false** portable lasers have health and safety issues

Answer 39

true

Question 40

**true/false** poli-lights have health and safety issues

Answer 40

true

Question 41

**true/false** portable lasers are safe to use around evidence

Answer 41

- FALSE - can damage if not careful

Question 42

**true/false** poli-lights are safe to use around evidence

Answer 42

true

Question 43

**true/false** poli-light cost has dropped over time

Answer 43

true

Question 44

**true/false** portable laser cost has dropped over time

Answer 44

true *(and size)*

Question 45

what are the diff kinds of brushed

Answer 45

- fibreglass - squirrel hair - camel hair - feather - magnetic wand

Question 46

what is the most commonly used brush

Answer 46

fibreglass

Question 47

what do we use squirrel hair brushes for

Answer 47

- **clean out** - if youve over applied, this can help clean out

Question 48

what do we use camel hair brushes for

Answer 48

- **clean out** - if youve over applied, this can help clean out

Question 49

what do we use feather brushes for

Answer 49

fine powders

Question 50

what do we use magnetic wand brushes for

Answer 50

metal powders

Question 51

how do we choose powders

Answer 51

- type and condition of **substrate** - **colour** of item/surface - *test a small are first to see if powder adheres and is good contrast*

Question 52

what ingredients are in granular ppowders

Answer 52

- *various ingredients* - most have C-based particles

Question 53

what colour is granular powders

Answer 53

various colours available

Question 54

what do granular powders adhere to

Answer 54

- moisture - oil - waste products in residue

Question 55

what are some cons of granular powders

Answer 55

- can be abrasive and damage print if over applied - can fill in print

Question 56

how do we use fluoresent powder

Answer 56

- use feather duster type brush *(cause its very fine powder)* - ALS to visualize - use proper PPE - consider glue fuming before powdering for better adherence

Question 57

what are metallic powders made up of

Answer 57

- fine particles of metals - *many aluminum based*

Question 58

what colour are metallic powders

Answer 58

light grey

Question 59

what brush do we use for metallic powders

Answer 59

fibreglass

Question 60

what surfaces do metallic powders work on

Answer 60

- highly polished and plated surfaces - *like silver, nickel, chrome*

Question 61

what surfaces do metallic powders not work on

Answer 61

some plastic or greasy surfaces

Question 62

what are magnetic powders made up of

Answer 62

- iron grit - and either aluminum or copper flake powder

Question 63

how do we apply magnetic powders

Answer 63

w magnetic wand

Question 64

what surfaces do magnetic powders work on

Answer 64

- shiny magazine covers - ceramics - boxes w coated surfaces

Question 65

what surfaces do magnetic powders not work on

Answer 65

magnetic surfaces

Question 66

what is the other name for cyanoacrylate

Answer 66

glue fuming

Question 67

how does CA work

Answer 67

- mix of heated glue + humidity - glue adheres to components of print residue - "fixes" print in place, less fragile

Question 68

what colour is CA

Answer 68

white

Question 69

what surfaces does CA work on

Answer 69

non-porous

Question 70

how do we use a glue fuming chamber work

Answer 70

- suspend items/ place on racks - add several drops of glue to dish + place on heater - water also placed on heater - 12 mins, dont wanna overfume

Question 71

what are common fluorescent dyes

Answer 71

- Rhodamine 6G - ardrox - basic yellow - MBD

Question 72

when do we use sticky side powder

Answer 72

- for treating the glue side of tapes *(especially duct tape)* - cause duct tape is often used when securing hands and feet of victims - *but also could be from mouth of victims so think of DNA*