What is the purpose of a developer in hair coloring?

The purpose of a developer in hair coloring is primarily to activate the hair color pigments. Developers contain hydrogen peroxide, which plays a crucial role in the coloring process. When mixed with hair dye, the developer opens up the hair cuticle, allowing the color molecules to penetrate the hair shaft. This activation is essential for both deposit-only color and permanent hair color, as it enables the color to bond effectively to the hair.

While other functions like moisturizing the hair, enhancing shine, and lightening hair strands may be achieved through other products or processes, they do not define the primary role of the developer in the context of hair coloring. The developer is fundamentally about facilitating the chemical reaction necessary for the color to work, making it an integral part of the hair coloring process.