Semi-permanent and permanent colours are usually applied to the whole head. This is done for cosmetic reasons, most notably to cover grey. To produce a colour lighter than one’s own the use of a lightening agent such as hydrogen peroxide is always needed. Off scalp colouring refers to the initial whole head colouring on scalp. The retouching of roots needs to be performed every 4-6 weeks in line with hair growth.
Highlighting - the use of a hair lightener on woven sections of hair; and low lighting - the use of a contrasting colour woven through the hair, are very popular forms of colouring.
Highlighting used to involve a single colour but now highlighting, Balayage and Ombre and baby lights.
Balayage is a French word meaning to sweep or to paint. This method uses many colours to create a highly textured effect. Ombre, the French for shadow, involves dark roots with colour gradually becoming lighter mid-head and a lighter tint on the ends of the hair. Baby highlights simply refer to very, very fine highlighting that is designed to produce an auric effect.
These are off-the-scalp techniques, and can be applied by the following methods:
Foiling is a technique where pieces of foil or plastic film are used to separate off the hair to be coloured; especially when applying more than one colour. This keeps the colour only on the desired pieces of hair and protects the rest of the hair.
Cap, when a plastic cap is placed tight on the head and strands are pulled through with a hook. This method is not frequently practiced anymore with the exception of short hair highlighting.
Hair colouring can create a youthful appearance by ridding it of the tell-tale greying hair. New looks can be created and makeovers completed by adding a new hair colour. Lightening hair can soften features of those with very pale skin. Blond hair is said to give the impression of increased levels of oestrogen, thus subliminally conveying youthfulness.
Repeated colouring and bleaching can dry out and damage the hair. Techniques and technology have advanced so far with hair colouring. Sometimes a very modern look in contrast with an older face can appear unnatural and a little odd.
Roots need to be touched up every 4 to 6 weeks depending on the speed of an individual's hair growth.