What should be used to protect the client's skin during hair coloring?

Using a barrier cream is essential for protecting the client's skin during hair coloring. This product acts as a shield, preventing the hair dye from coming into direct contact with the skin, which can minimize the risk of allergic reactions or skin irritation caused by the chemicals in the dye. The barrier cream helps to create a protective layer, allowing for a more comfortable application experience and reducing the chances of staining the skin.

While foil is often used for specific coloring techniques to separate sections of hair, it does not provide skin protection. Hair spray is primarily used to set styles and not related to skin protection during a color treatment. Water might dilute or wash away the dye and does not serve any protective purpose in this context. Thus, employing a barrier cream is the most effective method to ensure the client's skin remains safeguarded while achieving the desired hair color.