Colorado Cosmetology Written Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

The pH range for acid perms is between 4.5-7.0. This is because the acid in the perm solution helps to control the swelling of hair and minimize damage, making it suitable for delicate or damaged hair. Options B, C, and D have higher pH values, making them more alkaline and unsuitable for acid perms as they can cause more damage to the hair.