Which hair color products contain both a developer and color pigments?

The selection of permanent hair color as the correct answer hinges on the fact that this type of hair color formulation is designed to create a long-lasting change in hair color by using both a developer and color pigments. The developer, typically containing hydrogen peroxide, is essential for opening the hair cuticle and allowing the color pigments to penetrate the hair shaft. This combination not only deposits color but also can lighten the natural hair color, making it a versatile choice for achieving a variety of shades.

In contrast, semi-permanent hair color lacks the ability to lighten existing hair color since it does not contain a developer; it simply coats the hair with color molecules that wash out over time. Temporary hair color, similarly, does not involve a developer and only provides a superficial application of color that easily washes out after one or two shampoos. Hair bleaching products focus on lightening the hair and do not contain color pigments in the way that permanent hair color does. Thus, permanent hair color is uniquely characterized by its use of both a developer and color pigments, allowing for significant and lasting changes to the hair color.