Glitter Flashcards

1
Q

What is glitter?

A
  • Not the same as shimmer
  • Synthetic multilayered particles - plastic or aluminium, or a hybrid
  • Cut from rolled sheets, tend to be hexagonal, square or rectangle, or a custom shape
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where can glitter be found?

A
  • Decorative cosmetics
  • Sunscreens
  • Gel pens
  • Temporary tattoos
  • Glue
  • Paints
  • Woven in fabric
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is shimmer?

A
  • Mainly mica based
  • Used on its own (pearlescent effects)
  • Used as a substrate then coated with various metal oxides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How are interference pigments made?

A
  • Middle layer of mica (low refractive index)
  • Surrounded by metal oxide layer that has a high rerfractive index
  • Can be multilayered to give more discriminatory value
  • Thickness of metal oxide layers dictate colours reflected and transmitted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some alternative substrates to mica in interference pigments?

A
  • Borosilicate glass, silica, alumina
  • Thinner and more uniform than natural mica
  • Colourless (mica is slightly yellow)
  • Lower RI than mica - increases interference
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Glitter vs shimmer

A
  • Glitter is synthetic, mica based shimmer is natural
  • Mica alone or coated with metal oxides never contains plastic, glitter almost always does (or is aluminium based)
  • Glitter will have identically shaped and sized particles, shimmer particles are irregular and randomly shaped and sized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some recovery considerations for glitter and shimmer?

A
  • Should be analysed as multilayered paint flakes
  • Use a high intensity light source
  • Must not be lifted with J-Lar or acetate
  • Glass or plastic vial is best then a bag
  • Embedded particles must not be removed at scene
  • Dont refrigerate or freeze
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the analytical workflow for glitter?

A
  1. gross examination, recovery, collection
  2. preliminary evaluation of physical characteristics (microscopy of gauge)
  3. physical fit - manufacturing defects
  4. all microscopic techniques
  5. microspectrophotometry
  6. ATR infrared spectroscopy (plastic chemsitry)
  7. specific gravity
  8. raman micro spectroscopy (polymer layers)
  9. SEM-EDX - elemental composition of layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What should you look for with glitter evidence?

A
  • Number of particles and their physical dimensions
  • Location of particles
  • Number, sequence, thickness and colour of layers
  • Manufacturing defects, weathering, delamination, corrosion, damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can manufacturing defects tell you?

A
  • Probative value
  • Has the potential to match to a particular machine and so the manufactuer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What different analysis methods should be used when analysing glitter with microscope?

A
  • Oblique or alternate lighting as particles reflect differently
  • Alternate between black, grey, and white backgrounds to facilitate colour determinations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are benefits of glitter as trace evidence?

A
  • highly individualistic - different shape, thickness, size, number, morphology
  • nearly invisible
  • high probability of transfer and retention
  • quickly collected, separated and concentrated
  • easily characterised
  • databsing capabilities
  • relatively persistent and resistant to degradation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly