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
2
Q
Where can glitter be found?
A
- Decorative cosmetics
- Sunscreens
- Gel pens
- Temporary tattoos
- Glue
- Paints
- Woven in fabric
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
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
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
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
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
8
Q
What is the analytical workflow for glitter?
A
- gross examination, recovery, collection
- preliminary evaluation of physical characteristics (microscopy of gauge)
- physical fit - manufacturing defects
- all microscopic techniques
- microspectrophotometry
- ATR infrared spectroscopy (plastic chemsitry)
- specific gravity
- raman micro spectroscopy (polymer layers)
- SEM-EDX - elemental composition of layers
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
10
Q
What can manufacturing defects tell you?
A
- Probative value
- Has the potential to match to a particular machine and so the manufactuer
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
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