Lecture 13&14 - Makeup

Question 1

what cosmetic products that used to be used were found toxic and what were they replaced with

Answer 1

lead and mercury

replaced with Titanium and Zinc oxides

Question 2

what are the 7 main categories of cosmetics

Answer 2

decorative cosmetics
hair care
perfume
body care
sun care
oral care
skin care

Question 3

how can cosmetic evidence be characteristic of a person

Answer 3

everyone uses different products and if make up shades/colours of products

the order of these products will be different for every one

the application method also has an affect

Question 4

what is a cosmetic defined as

Answer 4

any substance or mixture intended to be placed in contact with 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

Question 5

name a product that is
a) a drug but not a cosmetic
b) both a cosmetic and a drug

Answer 5

a) anti dandruff shampoo
d) toothpaste with fluoride

Question 6

what products come under decorative cosmetics

Answer 6

nail varnish
foundation
blusher
lipstick
mascara
eyeshadow

Question 7

what can make categorising cosmetics difficult

Answer 7

they can have more than one use e.g bronzer can also be used as eyeshadow

• just because they have an intended purpose doesn’t mean they are used for this purpose always

Question 8

what makes decorative cosmetics good trace evidence (5)

Answer 8

easily transferred upon contact (two way transfers)

relatively persistent - can be hard to wash out

independent of age, gender, ethnicity

generally cover a large surface area

give investigative leads

Question 9

what could decorative cosmetics be used to cover up

Answer 9

blemishes, tattoos, hyperpigmentation, scars

Question 10

in the hierarchy of evidence, what level proposition can cosmetic traces give

Answer 10

activity level propositions

• so can be used to reconstruct an event

Question 11

what results in an increase in probative value of cosmetic evidence (3)

Answer 11

the use of uncommon cosmetics or layering different combination of cosmetics

also the mixture of cosmetic with different peoples skin

the application method used - brush or sponge

Question 12

are pigments or dyes more used in cosmetics

Answer 12

pigments

Question 13

what type of pigments are used in facial cosmetics

Answer 13

inorganic (mineral) pigments

Question 13

what type of Titanium dioxide is used for maximum opacity

Answer 13

pigment grade TiO2 particles = 0.25 micrometre

Question 13

what type of pigments are used in lipsticks

Answer 13

organic (lakes) pigments

Question 13

what does the particle size of a pigment determine

Answer 13

its properties

Question 13

what type of Titanium dioxide is used for sun creams

Answer 13

nano TiO2 particles = less than 0.1 micrometre

Question 14

what are non hiding white pigments used for in cosmetics and give some examples

Answer 14

used as extenders

e.g calcium carbonate
talc
china clay (kaolin)
silica

Question 15

what are the most important inorganic pigments in cosmetics

Answer 15

titanium dioxide
iron oxide (red, yellow, black)
bismuth oxychloride
mica
zinc oxide
ultramarine -
(blue/purple/pink)

Question 16

what are the most important metallic elements of cosmetics

Answer 16

aluminium flakes
iron oxide/TiO2 coated mica flakes

Question 17

what does pearlescent mean

Answer 17

a subtle colour and bright white reflection giving a pearl-like appearance

Question 18

what does interference/iridescent mean

Answer 18

light reflection and refraction with the colour changing relative to the angle of observation and illumination = rainbow-like appearance

e.g oil spill on water, CD surface, fish scales

Question 19

what is goniochromism

Answer 19

an effect where surfaces appear to change

Question 20

what determines the colour seen by iridescent and pearlescent substances

Answer 20

the thickness and composition of the layers that make them up

Question 21

how are the majority of iridescent material made

Answer 21

synthetically

Question 22

what are interference/iridescent pigments more commonly known as

Answer 22

shimmer

Question 23

what is shimmer very different to

Answer 23

glitter

Question 24

what are interference pigments made up of

Answer 24

layers of metal oxides on a mica substrates - tend to be 500nm thick e.g of metal oxides include titanium dioxide iron (II) oxide iron (III) oxide bismuth oxychloride SnO2 carmine chromium oxide ferric ferrocyanide

Question 25

what is mica and what can it be divided into

Answer 25

a naturally occurring silicate mineral (rock) can be divided into layers or flakes which can be translucent these layers can become coated in metal oxides resulting in different colours being observed

Question 26

what is a pearlescent pigment that becomes an interference pigment when coated on mic

Answer 26

BiOCl = bismtuh oxychloride

Question 27

what determines the colour seen of an interference pigment

Answer 27

the thickness and type of metal oxide that coats the mica substrate the number and order of metal oxide layers too - a mixture of metal oxides can coat the mica these things affect the colours reflected and absorbed

Question 28

what is a problem with using mica as the base substrate for interference pigments

Answer 28

mica is a finite resource so alternative sources will be needed

Question 29

what are alternative substrates to mica (3) and why are these good (3)

Answer 29

borosilicate glass silica alumina due to being synthetic these material can be made thinner and more uniform than natural mica they are colourless themselves (mica is slightly yellow) they have a lower RI (refractive index) than mica so increase the interference intensity

Question 30

what mode of SEM is better for looking at density

Answer 30

backspatter

Question 31

what do cosmetic traces have that fibres don't

Answer 31

better adhesive properties - likely to remain on clothing, bedding and other material like this this is due to cosmetics mixing with the oils in skin and being more naturally sticky compared to fibred

Question 32

what does a larger pigment particle size lead to in interference pigments

Answer 32

a brighter more metallic finish

Question 33

what four recovery consideration of cosmetic evidence is also used in fibre evidence

Answer 33

if garments are wet air dry in a controlled environment first store evidence in paper bags to prevent mould growth never package along with other debris from the scene if you can recover whole item then do it (control samples needed as close to samples as possible)

Question 34

how should cosmetic evidence be stored

Answer 34

at room temperature if possible but can be refrigerated if there is suspected DNA traces also

Question 35

why are moistened swabs not good for cosmetic trace evidence collected

Answer 35

they can hydrate the sample and possibly chemically alter it

Question 35

despite having the more probative value in other types of trace evidence, what step in the analytical workflow is not common in cosmetic evidence and why

Answer 35

a physical fit assessment cosmetic traces tend to be liquid transfers

Question 36

what is the general analytical workflow for cosmetic trace evidence

Answer 36

1. gross examination, recovery, collection 2. preliminary evaluation of physical characteristics 3. microscopic techniques 4. MSP - microspectrophotometry 5. IR spectroscopy 6. Raman spectroscopy 7. SEM-EDX 8. XRF 9. XRD 10. GC-MS and other chemical tests

Question 37

what is MSP used for

Answer 37

colour determination

Question 38

what is IR spectroscopy used for

Answer 38

organic content and silicones

Question 39

what is raman spectroscopy used for

Answer 39

inorganic pigments

Question 40

what is SEM-EDX used for

Answer 40

SE (secondary electron) mode for surface analysis and BSE (backspatter) mode for sample homogeneity

Question 41

what is XRF used for

Answer 41

elemental composition

Question 42

what is XRD used for

Answer 42

crystal structure and polymorphs

Question 43

what must we document of a suspected cosmetic transfer

Answer 43

the location on the substrates and the colour using visual analysis and then microscopic techniques for further examination

Question 44

what microscopic technique is particularly good for cosmetic analysis

Answer 44

fluorescence microscopy

Question 45

what must known and questioned samples be compared using

Answer 45

side by side comparisons with the same background colour also the same lighting angle and type

Question 46

what type of light is good for observing pigment distribution

Answer 46

transmitted light through the samples

Question 47

what type of light is good for observing layers or texture of a sample

Answer 47

reflected light from the sample

Question 47

what theory underlies the colour classification of cosmetic pigments - what three things make up this model

Answer 47

Munsell's colour theory - this is a 3D model based on the hue, value (brightness) and chroma (saturation) value 0 = black and 10 = white chroma 0 = neutral and there is no end value (approx 30) hue = five main colours (red, yellow, green, blue, purple) and the 5 in between each

Question 47

in microscopy, what background colours should be used to help with colour determination

Answer 47

black, grey and white q

Question 47

what is the chroma of a fluorescent pigment

Answer 47

30

Question 47

how can the presence of interference/iridescent pigments be identified in microscopic analysis

Answer 47

by changing the angle of the light hitting the sample or the position of the sample relative to the light to see if different colours are observed if different colours are seen when the angle of light is changed this suggests the presence of interference pigments

Question 47

what is another colour chart that could be useful particularly for facial cosmetics and why

Answer 47

Munsell soil chart iron oxide is a pigments found in facial cosmetics and it comes from dirt

Question 48

how can you tell apart natural and synthetic mica

Answer 48

using SEM-EDX natural has fluorine in it natural also has uneven edges whereas synthetic is likely to have smoother edges

Question 49

what are some things to note when observing cosmetics under a microscope and making comparisons

Answer 49

colour pigment distribution particle morphology surface features (edges) component encapsulation presence of mica or borosilicate glass

Question 50

how can you tell between borosilicate glass and mica substrates

Answer 50

borosilicate glass will be more translucent, have sharper edges and a uniform thickness

Question 51

what is something that companies will not often share that can impact identifying a cosmetic product

Answer 51

the exact product formulation

Question 52

does a forensic cosmetic database exist

Answer 52

no, there is a mineral one (RRUFF)

Question 53

why is raman chosen over FTIR is cosmetic analysis

Answer 53

raman can look at lower wavelengths with high accuracy and this is the region where information is relevant (below 500 cm-1)