What must barbers do before applying a chemical treatment?

Before applying a chemical treatment, performing a patch test is crucial for ensuring the client's safety and preventing any adverse reactions to the chemicals being used. A patch test typically involves applying a small amount of the chemical treatment to a discrete area of the client's scalp or skin, often behind the ear or on the inner arm, and monitoring for any allergic reactions or skin sensitivities. This process helps identify individuals who may have sensitivities or allergies to specific ingredients in the treatment, allowing barbers to take necessary precautions or make alternative product choices.

While washing the client's hair is often a part of preparing for a chemical treatment, it does not specifically address the safety concerns related to potential allergic reactions. Informing the client of risks is an essential part of the communication process, but it is secondary to the proactive measure of conducting a patch test first. Documenting the process, although important for maintaining records and providing quality service, is not a preparatory step for applying the treatment. Thus, conducting a patch test is the most critical step to ensure the client's safety before moving forward with any chemical applications.