1
Q
What were cosmetics used for in the past?
What ingredients were used?
A
- used to indicate tribe membership or protect against elements by painting yourself
- protect eyelids from sun
- naturally occurring products (clay, crushed gemstones, annatto (from tree), paprika, turmeric, seaweed, cochineal (carmine – comes from crushed up beetles), etc)
2
Q
When has there been sustained growth in cosmetic products since?
A
- since early 20th century
- steep dig in purchasing habits from 2020 onwards when people worked from home
3
Q
What are the seven main categories of cosmetics?
Which one are we interested in?
A
- oral care
- skin care
- body care
- perfume
- decorative cosmetics - this one
- hair care
- sun care
4
Q
What is a cosmetic defined as in the cosmetic legislation?
Who regulates cosmetic production in UK/USA?
A
any substance or mixture intended to be placed in contact with the various external parts of the human body…with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance and/or correcting body odours and/or protecting them or keeping them in good condition
UK - trading standards (in 2021) and advertising standards
USA - Food and Drugs administration (FDA)
5
Q
What is the difference between a cosmetic and a drug?
A
- some are drugs e.g. anti-dandruff shampoo is medicinal to treat dandruff
- some are both e.g. toothpaste with fluoride (cosmetic with drug to treat tooth decay) and concealer for acne (cosmetic with drug to treat acne)
6
Q
What does UK/FDA regard sunscreen as?
A
FDA - a drug but UK - not a drug
7
Q
What can be said about some components of cosmetics?
A
- some components are only authorised for use in a particular product e.g. some pigments used in makeup cannot be used on the eyes
8
Q
What are the eight categories of decorative cosmetics and who are these defined by?
A
- cosmetics Europe
1 - nail varnishes (nitrocellulose-based paint)
2 - foundations - mineral (rock based) or traditional (talc based although talc is hydrated magnesium silicate which is a mineral)
- this encompasses concealers, bb/cc creams, tinted moisturisers
3 - powders - finishing product
- mattify and set makeup underneath
4 - blushes
- bronzers and highlighters too
5 - lipsticks and lip glosses
- differences in compositions based on ratio of waxes to oils (lipstick have more wax than lip glosses)
6 - lip and eyeliners
- film formers, thickeners and pigment
- similar to paint compositions
7 - mascaras
- PVP, waxes, black iron oxide
- useful for determining who was driving when airbag goes off
8 - eyeshadows
- talc/mica based
- kaolin
boron nitride (replacement for talc as someone in US said talc causes ovarian cancer)
9
Q
What differs between decorative cosmetics?
A
- there are a variety of products
- there are lots of manufacturers (some own multiple brands) - this means their products may contain same ingredients
- there are lots of brands and product lines within the brands
- e.g. 9 foundations with different colours for each - will have different pigment concentrations
- excellent discrimination potential
- there are lots of different formulations
- loose powders, pressed powder, liquids, gels, mousses, sticks, creams
- lots of methods of application
- fingers, brush, sponge (wet/dry), contaminated with something else on brush
- mixtures
- cosmetic trace left behind is a mixture of all products that person has decided to wear
- all mixed up on face, mixed with sweat/sebum, mixed with fibres dropped on face, any pollen
- this provides a unique form of TE - will be very discriminatory
10
Q
What are some caveats with decorative cosmetics analysis?
A
- some cosmetics are multi purpose and someone can use product in place where it isn’t instructed to be used
- complicated trying to categorise cosmetic marks at scene - what products might they have come form
11
Q
What can be said about cosmetic trace value (cosmetic use, transfer, persistence, cases with no physical evidence, reconstruction, probative value, visibility)
A
- cosmetic use is increasing so more traces
- use is independent of age, gender, ethnicity and socio-economics
- not just used to beautify (cover scars, blemishes, tattoos and hyperpigmentation etc. (more likelihood of males wearing makeup)
- easily transferred, particularly with violent force
- relatively persistent and difficult to wash out
- good for cases with lack of standard physical evidence and where there is an absence of any matches on DNA/fingerprint database
- reconstruction of event - activity level propositions
- number, location and intensity of transfers
- uncommon cosmetics and layering combinations increase probative value
- e.g. cosmetics brought on holiday not sold in home country
- makeup deposits can be seen unlike perfume, shampoo, moisturiser, etc.
12
Q
Describe 1912 cosmetic trace value case study
A
- Marie Latelle was murdered
- main suspect was boyfriend but had alibi (playing cards with friends)
- Locard suspicious of circumstances as evidence of strangulation
- fingernail scrapings from boyfriend was looking for skin cells but found pink dust attached to these cells
- identified common makeup components (rice starch, bismuth, magnesium stearate, zinc oxide, red iron oxide)
- this pink powder was found in Marie’s room
- it was custom-made powder from chemist in Lyons
- found this was only ever made for Marie
- boyfriend convicted for murder
- alibi - he had wound the clock back so his friends gave him an alibi
13
Q
Do cosmetics prefer pigments or dyes?
What type?
A
- cosmetics tend to prefer pigments, not dyes
- mainly inorganic (mineral) for facial
- organic (lakes) for lipsticks
14
Q
What are non-hiding white pigments used for?
Give examples
A
- used as extenders
- calcium carbonate
- talc
- china clay
- silica
15
Q
What are A and R versions of titanium dioxide?
A
- denotes two polymorphs
- anatase and rutile
- they have the same CI number but very different crystalline structure so give vastly different raman structure
16
Q
What are two categories of special effect pigments?
How do they employ the effect they cause?
Describe their appearance
A
- pearlescent:
- gives a subtle colour and reflects bright white light
- ‘pearl-like’ lustre and look sheen
- interference (iridescent):
- reflect and refract light
- they distort light to give different effects
- colour changes relative to angle of observation/illumination
- ‘rainbow like’ - oil spills, kingfisher feathers, CD surface, fish scales (guanine)
17
Q
Define goniochromism
What causes this?
A
- phenomenon where surfaces appear to change
- guanine from fish scales
- found in high-end makeup products
18
Q
What are interference pigments also known as? and what is this not the same as?
A
- shimmer, not the same as glitter
19
Q
What is the composition of interference pigments like?
What is their thickness?
A
- metal oxide layers (TiO2, Fe2O3 etc.) coated on mica substrate (mica is a naturally occurring silicate mineral (rock) - use muscovite form in cosmetics)
- combination of type, thicknesses and numbers of layers of metal oxides gives you interference effects
- around 500 nm thick - therefore translucent
20
Q
What is structure of basic level of interference pigment?
How does this give interference effects?
What is a more advanced structure of interference pigment?
How is this used to dictate colours?
A
- mica is in middle sandwiched between TiO2
- or Fe2O3 instead
- mica has low RI and TiO2 has high RI (high opacity hiding white pigment)
- this distinction gives you interference effects
- it affects the way that light not only reflets off but transmits through so we see different colours
- colourant, titanium dioxide, mica, titanium dioxide, colourant
- where colourant = metal oxide
- metal oxide allows to create any colour you like
- thickness of metal oxide layers (and type) dictate colours reflected and transmitted
- colour wheel opposites
- if reflect yellow, transmit blue
- if reflect red, transmit green
21
Q
What are alternatives to mica?
What would the structure of these look like? give a basic and a more complex example
Do we need these yet?
What can be said about the properties of these alternatives
A
- borosilicate glass (Pyrex)
- silica (basically sand)
- alumina (aluminium oxide)
- borosilicate in middle, then protective layer than metal oxide chosen for desired effect
- borosilicate in middle, then TiO2, then SiO2, then TiO2 (gives different colours due to complexity of layering system)
- no worries at moment about mica but it is finite
- properties:
- thinner and more uniform (mica is natural but these are synthetically created so can control surface and make flatter/smoother
- colourless (mica is yellow which isn’t desirable if end result isn’t yellow
- lower RI than mica, only serves to increase intensity of interference effect
22
Q
What are secondary electron and back scatter modes better for looking at?
A
secondary electron - surfaces, topology and texture
back scatter - differences in density or chemical composition based on weight of atoms that are there
23
Q
How does pigment size dictate the intensity of the pigment?
A
larger pigment = larger plates = brighter = more metallic finish
24
Q
What are some recovery considerations for cosmetic traces (wet garments, debris from scene, liquid deposits, item recovery, refrigeration)
A
- air dry wet garments in controlled environment, store in paper bags to prevent mould growth
- never package with debris from scene
- cosmetic traces adhere better to garments/bedding/upholstery/carpets etc. as they are not solid materials like fibres
- solid to start with some of it but when applied to face and left there to mix with body oils once deposits as a trace it is a liquid
- therefore it adheres more and not looking at same evidence as fibres/paint evidence
- whole item recovery is preferable with collection of traces in a controlled lab environment
- stained areas should be protected from transferring onto other areas of object as location is important
- if immovable, samples must be collected for transfer and substrate using scalpel blade
- control sample as close to sample as possible but not on it
- refrigeration is dependent on DNA presence but it is preferable to be kept at room temp
25
What does Faculty of Forensic and Legal Medicine guidance say about the collection of forensic specimens from complainants and suspects in January 2023? What can be said about this guidance?
- for samples from hands, roll a moistened swab over hand or skin
- this is hydrating it and perhaps alters it
- all samples to be frozen
- not good for trace evidence, good for DNA
26
What is the analytical workflow for cosmetic traces?
- gross examination, recovery, and collection
- record general item type, dimensions, manufacturers label, markings, colour, logos/insignias, condition/damage
- record colour and location of suspected cosmetic traces
- preliminary evaluation of physical characteristics
- (physical fit assessment – most probative value but not really applicable when dealing with liquid transfers – not going to get a physical fit – can’t compare stain deposited on garment with missing part of makeup from someone’s face
- all microscopic techniques
- microspectrophotometry – colour determination
- infrared spectroscopy – organic content/silicones
- raman spectroscopy – inorganic pigments
- SEM-EDX – SE mode for surface topology & BSE mode for homogeneity and heterogeneity
- XRF – elemental composition
- XRD – crystal structure, polymorphs
- (Pyrolysis-GC/MS and Microchemical tests but destructive – try to avoid if absolutely necessary – should be last)
27
What does the visual colour determination of cosmetic traces involve? (values, what else can be used and why?)
- include hue, value (brightness) and chroma (saturation)
- HVC classification using Munsell's colour theory
- hues - 5 main plus 5 combinations
- values - 0 = black and 10 = white
- chroma - 0 = neutral, 15/20 = highly fluorescent
- can also use Munsell soil chart. why?
- look like facial cosmetic colours
- iron oxide pigments used in facial cosmetics are soil minerals and essentially come from dirt
- soil charts are going to be useful for recording an objective assessment of colour of a suspected cosmetic stain
- can say matches with x, y, z on Munsell soil chart
28
What does the microscopic techniques in the analysis of cosmetic traces involve? (lighting to use, backgrounds to use, illumination methods to use, what else recommended, what observable differences to look for?)
- stereoscope
- consider oblique/alternate lighting as particles reflect differently e.g. interference pigments will change appearance dependent upon angle of incidence light and angle which they are observed
- alternate between black, grey, and white backgrounds to facilitate colour determinations (background affects what we see especially if pigments are translucent)
- different ways to illuminate sample: transmitted light for observing pigment distribution and reflected light for layers/textures - use both
- use fluorescence - experts recommend fluorescence
- colour matrix/particles
- distribution of pigments
- particle morphology
- surface topology
- mica vs. synthetic (also SEM-EDX!)
- borosilicate glass – can see if got this
- PMMA/silica spheres (also RI measurement)
- component encapsulation (encapsulate stuff into vesicles that almost either burst on contact with skin or with friction of being painted, sponged, rubbed on with fingers)
29
How can we tell the difference between naturally occurring mica and synthetic mica?
- synthetic mica is synthetic fluorophlogopite
- this has fluorine in it
- using SEM-EDX, if has fluorine then know we have synthetic version
30
How can we tell the difference between borosilicate glass and natural mica?
- borosilicate glass is more translucent and has very distinctive sharp edges (looks like glass)
- whereas mica has a more natural look - rounded edges, non-uniform appearances and differences in thickness
31
What is advantage of raman over FTIR?
- raman cuts at 75 wavenumbers where as FTIR starts at 500 (at 400 just get noise)
32
Why is cosmetic analysis complex? (class characteristics, mixtures, formulations, RRUFF database, cosmetic trace database, research)
- may only ever get class characteristic e.g. product type
- because people use use lots of different products in different ways with different application methods on different skins on different skin care – have potential for unique discriminating mixes – have potential to then be individually characterised
- cosmetic formulations are not shared
- get ingredient list on back but doesn't show proportions
- RRUFF database is for minerals only (good for TiO2, mica, bismuth oxychloride, iron oxides etc.)
- no forensic cosmetic database exists and even if one did exist it would have little value as product formulations change rapidly and change under context - what else they have been applied with
- deposited traces are highly unlikely to represent initial product from which it came from so a database of freshly deposited cosmetics on microscope slides in lab is unlikely to match anything picked up from crime scene
- very little research on background, transfer, persistence, contamination and activity level
33
What does the rarity of makeup increase?
- rarity of makeup increases its probative value
34
What are important considerations when interpreting cosmetic traces? (substrate considerations, multiple associates, nature of contact, two-way transfer, other considerations)
- substrate considerations - absent of cosmetic trace doesn't mean one wasn't left there (it may have slipped off)
- multiple associates mitigate coincidental transfer (multiple stains in multiple locations will go against someone who says it was an accident as i brushed past someone)
- nature of contact/forces involved
- intensity of colour, amount deposited, where it is deposited are affected by nature of contact/force
- two-way transfer also applies
- numerous considerations with transfer, persistence, interaction with skin, age of product, removal etc.
- has sun/microbes/animals degraded it
- has someone tried to wash their skin or launder garments
35
Why are cosmetic stains overlooked?
What are the cavates?
- cosmetics are even more overlooked than other forms of trace evidence - some don't even consider it a form of trace evidence
- caveats:
- expensive
- time-consuming
- requires skilled analysis
36
What are some things that experts have said about cosmetic trace evidence?
- unlikely that any cosmetic trace recovered will reliably compare with original product – Robert (Bob) Blackledge
- no specific guidance about cosmetic traces, I tell them to treat it like paint or grease – Richard Hunt
- cosmetic analysis is carried out but on a very minor scale and not shared – Chris Brereton
- no personal experience of collecting any cosmetic traces found at crime scenes – Bob Green
- we do not collect cosmetic samples even if they are readily apparent – Phill Pemble
- no cosmetic samples are taken from the cadaver at post mortem…missed opportunity – Andrew Langley
37
What are two cases where cosmetic evidence used?
- William Heirens - lipstick evidence used for handwriting analysis
- Curtis Sims - used theatrical makeup (higher content of hiding white pigment-TiO2 to conceal facial tattoos during bank robbery
FSCI6030 - Trace Evidence
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