have to use the most
powerful bleaching chemicals available. They would certainly
damage her hair to a marked extent. It would be less damaging
to carry out the process in several stages - up to a dozen,
perhaps. During that time her hair would change from black to
red, and then lighten gradually from red to orange, orange to
yellow, and finally from yellow to white. Some of the stages
might well have to be repeated.
The stylist might decide that a three-step
or five-step programme would be possible, changing first from
black to red, then from red to yellow, and finally to white.
What has to be considered before any final decision is taken
is how to keep damage to the cuticle to a minimum, and above
all what will be the final effect of the programme on the quality
of the hair.
| HAIR
FACTS |
How
lightening works
The oxidising agents in bleaches take part in a
chemical reaction with melanin. They provide the
melanin molecule with oxygen from their own molecules.
The oxidised melanin molecule is colorless.
Melanin is contained in the cortex of
the hair. For the oxidising agent to reach the melanin,
therefore, it has to get through the cuticle. In
the alkaline solution of the bleach formulation,
the scales of the cuticle are raised and the bleach
chemicals can then penetrate the cortex. |
|
Problems
in the bleaching process
Raising the scales of the cuticle for penetration
by the bleach is in itself a potentially risky process. Repeated
bleaching can leave permanently raised
scales and upset the moisture content. It increases the porosity
of the hair, and this makes further bleaching
more difficult: very porous hair bleaches badly, with uneven
shading. Repeated bleaching leaves weak, brittle hairs which
have little shine or lustre, and which weather rapidly. Additional
cosmetic procedures such as perming simply make things worse.
|
|
Dark
hair highlighted using the 'Sun In' treatment
|
