What is the primary function of a toner in hair coloring?

The primary function of a toner in hair coloring is to neutralize unwanted tones. Toners are typically used after the initial hair dye application, especially for those who lift their hair color to a lighter shade. Lightening can sometimes result in brassy or unwanted tones, such as yellow or orange hues.

Toners help to adjust the final color by adding pigments that counteract these unwanted undertones. For example, a purple toner may be applied to neutralize yellow tones, while a blue toner can help eliminate orange tones. This creates a more balanced and desirable hair color.

While toners can sometimes provide a glossy finish, their main role is to refine the hair's color rather than to enhance shine. Additionally, they do not lighten the hair further or increase its volume, which are functions associated with different hair products and processes. Thus, the correct understanding of the primary function of a toner highlights its role in correcting and enhancing hair color.