Final answer:
The time allowed for a permanent waving service can vary from 1.5 to 3 hours on average. During the process, the hair is prepared with a waving lotion, reshaped, neutralized, and styled.
Step-by-step explanation:
The time allowed for a permanent waving service can vary depending on factors such as the type and thickness of the hair, as well as the desired result. However, on average, a permanent waving service can take anywhere between 1.5 to 3 hours.
During a permanent waving service, the hair is first prepared by applying a waving lotion or solution, which breaks the disulfide bonds in the hair. This allows the hair to be reshaped into the desired curl pattern. The hair is then wrapped around rods or other tools to create the desired shape and left to process for a certain period of time.
After the processing time, the hair is rinsed and a neutralizer is applied to reform the disulfide bonds and lock in the new shape. The neutralizer is usually left on the hair for a few minutes before it is rinsed out, and then the hair is styled and dried.