What is the function of a toner in hair coloring?

The function of a toner in hair coloring primarily revolves around correcting or adjusting unwanted color tones in the hair. Specifically, toners are designed to neutralize brassy yellow or orange undertones that may appear after the lightening process. This is especially important for achieving a desired shade, such as a cool blonde or ash tone, which can be affected by underlying pigments that become more prominent during hair lightening.

Toners contain various pigments that target specific unwanted hues. For example, purple toners counteract yellow tones, while blue toners are effective against orange hues. By applying a toner after the initial hair coloring has occurred, hairstylists can refine the final color and achieve a more balanced and aesthetically pleasing result.

Other options presented do not accurately describe the primary role of a toner. Lightening hair is accomplished through bleach or lightening agents rather than toner. Adding volume is typically the function of hair products like volumizing sprays or mousses, and speeding up the coloring process is not a characteristic of toners, which are instead often used as a finishing step.