In 1938, Arnold F. Willatt invented the cold wave, the precursor to the modern perm. It used no machines and no heat. The hair was wrapped on rods and a reduction lotion containing ammonium thioglycolate was applied. This chemical breaks open the disulfide linkages between the polypeptide bonds in the keratin (the protein structure) in the hair. The disulfide bonds give hair its elasticity, and can be reformed with chemicals. Next, an acid neutralizer lotion was applied, (hydrogen peroxide), to close the disulfide bridges again and the hair was reformed to the shape of the rod. The entire process took 6-8 hours at room temperature.Perms today use this method with sodium thioglycolate instead of ammonium thioglycolate, at a pH of 8 to 9.5. This method takes only 15-30 minutes until the neutralizer is applied to bring down the pH and rebond the hair.In the 1970s, acid perms were invented. These use glycerol monothioglycolate instead and contain no ammonia. They are sometimes called buffered waves. This perm is slower but gentler to the hair. Heat is usually added by placing the client under a dryer, after covering the wrapped head with a plastic cap. The reaction is endothermic and the additional heat causes the pH to rise from 6.9 to 7.2.
Other types of modern perms include exothermic perms, which are self timing and self heating; and neutral, or low pH, thioglycolate free perms.The permanent relaxer straightens the hair instead of curling it. The same chemical methods can be used for this, but the hair is not wrapped around rods. This process is commonly used by African-Americans and others with naturally curly hair.
There are two parts to a perm, the physical action of wrapping the hair, and the chemical phase. Both of these can affect the result. Important physical variables involved are what type of rod is used, how the hair is wrapped and how end papers are used. The two most common types of rods are straight and concave; each giving a different curl effect. The wrapping method is either spiral or croquinole, and various types and positionings of end papers can be used with any combination of the above. Generally, smaller rods will produce smaller, tighter curls and increase the appearance of shortening the hair.
The chemical solution used in the perming process is determined by the client's hair type and the pH of the solution. Classic alkaline perms are used for stronger, coarser hair. They work at room temperature and usually contain ammonium thioglycolate in the pH range of 9-10. Acid perms are used on more delicate or thinner hair. They require outside heat application and usually contain glycerol monothioglycolate in the pH range of 6.5-8.2.Due to the harsh nature of the chemicals, it is important that contact with the skin be minimized. Modern chemicals are less irritating, but measures should still be taken to reduce contact with anything other than hair.
A poorly performed permanent wave will result in breakage of the disulfide bonds through chemical reduction, because it fails to fix the newly formed bonds. This results in hair that is no longer elastic and flexible, but brittle and fragile. At this point, even combing the hair will result in hair loss. The hair shafts will experience fracture where they exit the scalp. Because the bulb of hair has not been removed though, the hair follicle is not damaged and the hair will regrow; however, the temporary hair loss may be distressing.Home perms
The chemical solution used in the perming process is determined by the client's hair type and the pH of the solution. Classic alkaline perms are used for stronger, coarser hair. They work at room temperature and usually contain ammonium thioglycolate in the pH range of 9-10. Acid perms are used on more delicate or thinner hair. They require outside heat application and usually contain glycerol monothioglycolate in the pH range of 6.5-8.2.Due to the harsh nature of the chemicals, it is important that contact with the skin be minimized. Modern chemicals are less irritating, but measures should still be taken to reduce contact with anything other than hair.
A poorly performed permanent wave will result in breakage of the disulfide bonds through chemical reduction, because it fails to fix the newly formed bonds. This results in hair that is no longer elastic and flexible, but brittle and fragile. At this point, even combing the hair will result in hair loss. The hair shafts will experience fracture where they exit the scalp. Because the bulb of hair has not been removed though, the hair follicle is not damaged and the hair will regrow; however, the temporary hair loss may be distressing.Home perms
A number of brands of home permanent kits are available, but their numbers have decreased as permanent waves are not as popular as they were in the 1980s. The first popular home permanent was the Toni brand. The Toni company used a set of twins to advertise their products — one with a salon perm and one with the home perm. Another brand that was a household name in Britain in the late 1960s and 1970s was Twink.
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