What should you do before applying a chemical treatment to the hair?

Before applying a chemical treatment to the hair, performing a strand test is essential. This test involves applying the chemical to a small section of hair to evaluate how it reacts. It helps determine the hair's suitability for the treatment, including how well the hair can handle the chemicals and the final result of the application. A strand test can reveal potential issues such as damage, breakage, or unexpected color results, allowing the barber to make necessary adjustments or decide whether to proceed with the treatment.

While conditioning hair, consulting with the client, and washing the hair can all be important steps in a hair treatment routine, they do not specifically assess hair's compatibility with the chemical treatment, which is critical for achieving the desired results and ensuring the health of the hair. Therefore, performing a strand test is the most crucial step to take beforehand.