Permanent wave

A permanent wave, commonly called a perm or "permanent", involves the use of heat and/or chemicals to break and reform the cross-linking bonds of the hair structure. The hair is washed and wrapped on a form and waving lotion or 'reagent' is applied. This solution reacts chemically softening the inner structure of the hair by breaking some of the cross links within and between the protein chains of the hair. The hair swells, stretches and softens, then molds around the shape of the form.

In addition, the process is often used for the chemical hair straightening, or relaxing (a process first developed by Renaud Whittington). This process makes use of the same chemical reactions as that of the permanent wave, but the hair is combed straight rather than wrapped around forms.

The first person to produce a practical thermal method was Marcel Grateau in 1872. He devised a pair of specially manufactured tongs, in which one of the arms had a circular cross-section and the other a concave one, so that one fitted inside the other when the tongs were closed. The tongs were generally heated over a gas or alcohol flame and the correct temperature was achieved by testing the tongs on a newspaper;if the paper browned slightly it was about right. The waving itself was safe if care was taken to keep the tongs away from the scalp. The procedure was to comb a lock of hair towards the operator, moving the comb slowly with one hand to maintain some tension, while applying the tongs to the hair successively down the lock of hair towards the point. Each time the tongs were applied, they were moved slightly in a direction normal to the lock of hair, thus producing a continuous flat or two-dimensional wave. Skill using the wrist could produce slight variations of the wave. Thus, Marcel waving produced a two-dimensional wave, by thermal means only and the change was produced by plastic flow of the hair, rather than by any chemical means. Because of the high temperature used, the process tended to degrade the hair. However, in spite of its drawbacks, forms of Marcel waving have persisted until today, when speedy results and low cost are important.

As the demand for self-determination grew among women, hair was shortened so that it did not pass the lower end of the neck. This was not only a political gesture but a practical one, as women began to take over men's work due to the great shortage of labour during the First World War (see Suffragette). At the same time, electricity, which had been introduced mainly for lighting and industrial use, began to be used for heating and the application of the electric motor at the small business and domestic level. As shorter hair was improved in appearance by waving even more than long hair, it was only a matter of time before an improved form of waving appeared.

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