What is the role of a developer in hair coloring?

The role of a developer in hair coloring is primarily to open the hair cuticle. Developers contain hydrogen peroxide, which acts as an oxidizing agent that allows the color to penetrate the hair. When mixed with hair color, the developer lifts the cuticle scales, making it easier for the pigment to enter the hair shaft. This process is essential for achieving the desired color, especially in permanent hair dyes, where the developer works with the color molecules to create a long-lasting effect.

While conditioning the hair, providing color pigment, and adding shine are important aspects of hair coloring, they are not the main function of the developer. Conditioners and shine enhancers may be incorporated into some hair color products, but they do not define the developer's role. The primary function of the developer is to facilitate the opening of the hair cuticle so that the color can successfully be deposited within the hair structure.