Over-bleached hair: the damage is all too obvious
Bleaching is not the only effect of treating
hair with oxidising agents. Side-reactions often
happen, such as breakage of some of the strong
disulphide bonds of the hair. Re-bleaching, which
means treating the whole length of the hair rather
than just the roots, is certain to break more
of these.
The cuticle is especially easily
weakened in this way. As a result it becomes extremely
easy to strip it away from the cortex, even during
routine hair care. Wet combing, for instance,
becomes more difficult and causes additional damage.
Backcombing is especially damaging because it
can removes large amounts of cuticle with a single
sweep of the comb.
Bleached hair, being porous,
swells more readily when it is wet, and its wet
strength is reduced still further. Eventually
the hair protein may become so weakened that it
separates and the hair breaks.
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Permanent hair color
This is the kind of hair coloring that is used
most commonly throughout the world. It is the type
that has to be used if a
complete change of hair color is required. Highlighting
or coloring just part of the hair using a permanent
color is possible, however.
When changing hair color, it
is wise not to make a permanent change of color
all at once, especially if the new color will be
very different from the old. It is sensible to try
a temporary color first: this can be washed out
straight away if the effect is disappointing. The
next step would be to use a semi-permanent dye.
Only if this is successful would it be advisable
to move to permanent coloring, and that is something
that should ideally be done by a professional.
The two-step coloring
process starts by stripping the hair of all the
melanin that gives it its natural color. Hydrogen
peroxide in 30-40% solution is used. This is one
of the harshest of all procedures used on hair,
because the bleach destroys hair keratin. The hair
can look lifeless when bleaching is complete, and
another chemical process
follows, using a new color.
A more typical procedure uses
a gentler bleach (20% hydrogen peroxide solution)
together with a dye and an alkaline soap or synthetic
cleansing agent.
Allergies have been reported after
the use of permanent colors, especially preparations
containing the chemical ammonium persulphate. It
is always wise to carry out a patch test on a client's
skin before using any coloring process, in case
there is any possibility of irritating, unsightly
or painful allergy following the treatment. No coloring
agent should ever be used on a client who is showing
clear signs of dermatitis.
When shampooing after hair coloring,
or indeed after any chemical processing of hair,
use a shampoo with an acid balance as this will
help the cuticle scales to close up and lie smooth
again.
With regular professional re-tinting,
using the same product, the hair can be kept the
same color for as long as required.
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