In haircoloring, what is the primary goal of using a toner?

The primary goal of using a toner is to adjust the underlying tones in the hair color, particularly to neutralize or modify unwanted yellow or brassy tones. After the hair has been lightened, whether through bleaching or other coloring methods, it can often have warm undertones that are not desirable for the final look. Toners usually contain color pigments that help achieve a more balanced and aesthetically pleasing shade by counteracting these unwanted hues. This is especially important for achieving cooler shades, such as ash blondes or cool browns.

While adding shine and enhancing color is a benefit of some toners, that is not their main purpose. Similarly, while a toner can contribute to a more harmonious overall color, it doesn't achieve a significant lightening effect or create a permanent color change, which are objectives associated with other coloring techniques or processes, rather than toning. Therefore, the role of toner is specifically aligned with modifying existing color tones, particularly to target and neutralize unwanted warmth.