What is the purpose of using a developer when coloring hair?

The use of a developer in hair coloring serves as a critical component that activates the hair color and opens the hair cuticle. When a developer is mixed with hair color, it usually contains hydrogen peroxide, which plays a dual role in the coloring process.

First, it helps to lift or lighten the natural pigmentation of the hair. This is essential for achieving the desired hair color, especially if a lighter shade is chosen than the individual's natural hair color. Secondly, the developer activates the color molecules, allowing them to penetrate the hair shaft effectively.

Opening the hair cuticle is necessary for the color to adhere properly and produce long-lasting results. Without the developer, the hair color would not penetrate, leading to poor color retention and richness. This process is fundamental to achieving vibrant and even hair color, making the use of a developer an essential step in hair coloring.