What defines cold waves in perming?

Cold waves, also known as alkaline waves, are characterized by not requiring external heat for their chemical process. Instead, they rely on the heat generated by the exothermic reaction of the perm solution itself as it processes the hair. This means that the chemicals in the solution open the hair cuticle and reform the disulfide bonds, allowing the hair to take the new shape of the curl.

The significance of this property is that it provides more flexibility and minimizes the risk of heat damage, particularly beneficial for different hair types. Since cold waves do not utilize added heat, they result in a more even setting of curls and have the ability to create more defined and long-lasting styles compared to other perm techniques that require heat.

Other options may refer to specific aspects that do not apply to cold waves, such as the requirement of heat, the type of solutions used, or the composition of ingredients. Understanding the defining characteristic of cold waves as being heat-free helps in distinguishing them from other perming methods, thus reinforcing the importance of this fundamental concept in perming technique.