What is the primary function of a cold wave in perming?

The primary function of a cold wave in perming is to create curls without the use of heat. Cold waves, or alkaline perms, utilize chemical solutions that break down the hair's disulfide bonds, allowing the hair to be reshaped into curls or waves. This process does not require the application of heat, distinguishing it from hot perms, which rely on heat to aid in the curling process. Cold waves are particularly effective for producing defined curls and provide a lasting curl pattern once the chemical solution is neutralized and the hair is rinsed. This technique is valued for its ability to effectively curl hair while minimizing potential heat damage, making it a popular choice in salons. The focus on chemical processes rather than thermal methods is what sets cold waves apart in the perming technique.