What should be done to prepare hair before applying a lightening color treatment?

To properly prepare hair before applying a lightening color treatment, using a clarifying shampoo is essential. This type of shampoo is specifically designed to remove buildup from styling products, oils, and other impurities that may have accumulated on the hair. By cleaning the hair thoroughly, it ensures that the lightening treatment can penetrate the hair shaft more effectively, leading to a more even and successful color result.

In contrast, applying a leave-in conditioner may add moisture that could interfere with the lightening process, while cutting the ends of the hair is irrelevant to preparing for a color treatment. Using a deep conditioning treatment, although beneficial for damaged hair, may not be advised immediately prior to lightening because it could also add layers of product that might hinder the lightening process. Thus, washing with a clarifying shampoo is the most appropriate step to ensure a clean canvas for the lightening color treatment.