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Having your skin examined under the microscope can be a chastening experience
– particularly if it is done in public at the cosmetics counter of a department
store. If you have never given its condition more than a fleeting thought,
you may be horrified at what a latex cast of part of your face reveals.
The skin is likely to be too dry, or too oily, or – if you are doubly cursed
– both. But have no fear, a consultant is on hand to recommend just the
lotion to restore that all-important balance of oils and moisture and protect
your face from the ravages of weather and ageing.

Skin analysis under the microscope, available from the Shiseido counter
at the Harvey Nichols store in London, introduces a little objectivity into
the highly subjective area of skin care. It is one of the simplest tests
of skin condition that can be done. The beauty consultant cleans the skin
on the highest point of the cheekbone, then mixes a quick-setting latex
paste and smooths it on. Three or four minutes later, she peels it off,
looks at it under an optical microscope, and explains how the pattern of
tiny wrinkles and pores reveal the skin’s condition. Large, irregular pores
show oiliness. Skin which is stretched out flat is too dry. Shiseido claims
that with the right combination of its products you can have normal, healthy
skin – slightly plump with small, regular pores.

Manufacturers of cosmetics are often accused by sceptics of making totally
unscientific claims. But, as Caroline Crawford of the Advertising Standards
Authority points out, the ASA’s code of conduct ‘requires that evidence
for cosmetic claims must be backed up by clinical trials on humans. We ask
that they have been accepted by the medical profession – it’s not enough
to test twenty people and say it’ll work on everyone.’ The code can be enforced
legally. A London spokeswoman for L’Oreal, the French cosmetics and pharmaceuticals
manufacturer, says: ‘We can’t say an anti-wrinkle product reduces the depth
of wrinkles unless we have the information to back it up.’ Typical claims
for skin creams in L’Oreal’s Synergie range are ‘wrinkles and fine lines
will appear reduced’ and ‘helps drainage of toxins formed around the eye’.

Crawford says advertisements that claim cosmetics can physically change
the structure of the skin, or achieve permanent changes, are not acceptable.
Advertisements that use pseudoscientific, invented or vague terms – such
as ‘active natural extracts’, ‘tonicity’ or ‘ingredients that closely resemble
the make-up of your face’ – are passed, provided they are not judged to
be misleading. ‘We discourage (advertisers) from baffling people with science,’
says Crawford. But cosmetics manufacturers are well aware of the selling
power of science. They are increasingly using scientific tests not only
to provide evidence about the safety and effectiveness of their products
but also to assess their more esoteric properties, such as the ‘feel-good
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All the big cosmetics companies test new products to ensure they work.
They run experiments to see, for example, how dyed hair fades in sunlight,
how slippery a conditioner leaves the hair, and to what extent anti-wrinkle
creams change the texture of skin. L’Oreal’s researchers test wrinkle cream
in a similar way to Shiseido, by taking silicone rubber casts of the surface
of a volunteer’s skin. The casts are made before and after a two to three-week
course of treatment with a product such as L’Oreal Plenitude Active Wrinkle
Control. Examination under a scanning electron microscope clearly shows
the depth and extent of the wrinkling.

L’Oreal, which owns the brand names Lancme, Labo-ratoires Garnier and
Helena Rubenstein, has four research laboratories in Paris, employing 1500
researchers in cosmeticology and dermatology. The laboratories are partly
automated, with robots carrying out repetitive tasks such as hair combing.
Tests are standardised as far as possible – for example, locks of hair of
the same weight and length are tangled up by a machine rolling across the
strands. Then conditioners are applied and the combing robot sets to work
to show which conditioner is the best untangler.

Researchers at L’Oreal test hair-setting lotions and perms on a robot
head – a metal box with sloping sides. Locks of hair which have been treated
with different chemicals are fixed to the sides. The box is then jerked
about by a motor to simulate the bouncing and buffeting that hair receives
in everyday life. As the curl relaxes, the locks sag downwards, and the
rate of sag gives a measure of the strength of the set or perm. Shine is
assessed by measuring how much light is reflected by the hair. Newly dyed
hair is put to the ‘Xenotest’ to see how the dye fades. This involves subjecting
hair under conditions of varying humidity to the glare of a high-intensity
xenon lamp which simulates the effects of strong sunlight. Elida Gibbs of
London, whose brands include Pears, Timotei and Brut, examines hair shafts
under an electron microscope to check their condition.

But the cosmetics manufacturers recognise that all this is not enough.
A product, no matter how effective, will not sell unless it feels and smells
good too. Testing for the feel-good factor usually requires getting subjective
reactions to new concoctions. L’Oreal’s spokeswoman says: ‘We have an enormous
testing salon with about 400 seats and mirrors, and we have a register of
9000 volunteers who come in regularly to have half their head shampooed
with the old formula and half with a new.’ Testers at Boots the Chemists,
which has its headquarters at Nottingham, ask hairdressers to score new
shampoos against criteria such as how well they foam and rinse, their creaminess,
stability and texture. Volunteers assess the feel, body and manageability
of their hair after a wash, as well as how easy it is to comb it.

Right formula

What cosmetics manufacturers would really like from their scientists
is an empirical way of measuring this feel-good factor. Life would be so
much simpler if their physicists and chemists could pretest customer reaction
to a product in the laboratory. Smell, feel and appearance all play a part.
Appearance is normally straightforward to measure, for example, by testing
colour and homogeneity. Perfumiers, however, still rely on their own noses
to test scent. And qualities such as friction – which is vital to the feel
of soaps, shampoos, moisturisers and hair conditioners – is extremely difficult
to analyse. Brian Briscoe, professor of chemical engineering at Imperial
College, London, says: ‘People don’t like to feel high friction because
it pulls the skin, or low friction, because it feels greasy and dirty.’
He believes that manufacturers would give a lot for an equation to relate
the measured coefficients of friction to its feel-good effect.

Leszek Wolfram of the German Wool Research Institute in Aachen has
shown that friction depends much more on the properties of the hair than
the properties of the comb. This is good news for the makers of hair-care
products – tests for friction in the laboratory can dis-regard the effects
of combs and brushes, which in the real world are beyond their control.

Wolfram has found that when combing hair, the most important source
of friction is between individual hair fibres. He reckons that, for dry,
straight hair, the average force between two contacting hairs (N) is 30
micronewtons and the coefficient of friction (mu) is 0.3. This means the
average frictional force when two hairs touch, which equals mu x N, is 10
micronewtons. Each centimetre of hair has around 2.2 contacts with other
hairs. An average hair is 15 centimetres long and there are 100 000 hairs
on the average head. By increasing the overall friction, hair will stay
put in all sorts of styles, whereas decreasing the friction will cause it
to slip. So tests based on Wolfram’s measurements could have applications
for the makers of setting lotions and styling mousses.

However, the friction associated with shampoos and hair conditioners
relies on a further factor. Wet hair can carry a third of its own weight
in water, affecting its properties significantly. For example, the coefficient
of friction between wet hairs is higher than between dry hairs. But Wolfram
says the surface tension of the water has an even greater effect. If the
hair is straight, ‘the surface tension of the water brings the fibres together,
increasing the force between two contacting hairs to 35 micronewtons’. Because
of this, straight hair is about two and a half times as hard to comb when
wet. However, very curly hair, such as Afro hair, behaves differently. Because
the hair shafts curl around rather than being almost parallel, surface
tension from the water does not draw them together. In fact, it actually
reduces friction by relaxing the curls and so cuts down the number of contacts
between individual hairs. This type of hair is two and a half times easier
to comb when wet than when dry.

Hair that is chemically straightened or permed can swap between these
two types. Wolfram says this information is of use to researchers developing
new hair products. But outside the laboratory, people have tresses in all
states of health and condition. Wolfram’s conclusion will make depressing
reading for cosmetic manufacturers aiming to predict their customers’ reactions
to new products. Trial and error, it seems, is a quicker way to find a grooming
routine that works than calculation and experiment.

Even if mathematical formulas could help cosmetics manufacturers get
the right product on the market, they never forget that their relationship
with customers is one that requires nurturing. Briscoe describes the delicate
business of keeping customers happy as ‘psycho-physics’. At the top end
of the market there is clearly more psycho than physics. At Shiseido, for
example, the beauty consultant, armed only with a microscope and polarising
filter, can ‘visualise the condition of your skin’s future’. She will pamper
and mollycoddle you, discuss your needs and lifestyle, even send you a birthday
card. Your skin won’t be young forever, but there’s no denying the feel-good
factor.