What is the purpose of applying toner to hair?

The purpose of applying toner to hair primarily revolves around adjusting the tone of the base color. Toner is used after the bleaching process to refine the color by neutralizing unwanted undertones. For instance, when hair is lightened, it may have brassy or yellow shades. Toners can help achieve a cooler, more desirable shade by introducing various pigments that counteract these brassy tones. This adjustment is crucial for achieving a more polished and vibrant final result, especially in color-treated hair.

In contrast, moisturizing the hair is typically associated with conditioning products, while adding shine is generally more linked to serums or glossing agents. Strengthening hair usually involves treatments designed to repair or fortify the hair structure rather than altering its color. Therefore, the application of toner specifically serves the key role of refining the color tone, making it the correct choice in this scenario.