What is the definition of a double-process application in hair coloring?

In hair coloring, a double-process application refers to the technique of coloring the hair in two distinct steps. This process typically involves first lifting the natural hair color using a lightening agent, followed by the application of a desired hair color or toner. This method is particularly beneficial when aiming to achieve a shade that is lighter than the natural color, as it ensures that the hair is adequately prepped to accept the new hue evenly and effectively.

By breaking the process into two separate stages, the stylist can control the lightening process more effectively and prevent damage, allowing for a more vibrant and desirable end result. It's an essential technique for achieving high fashion colors, pastel shades, or any look that requires significant alteration of the natural color.