What is the purpose of a toner in hair coloring?

A toner is specifically designed to adjust the undertone of bleached or pre-lightened hair. When hair is bleached, it often takes on unwanted tones that can range from yellow to brassy orange. The role of the toner is to neutralize these undesired pigments and create a more balanced and aesthetically pleasing color. Toners typically contain violet or ash pigments that target these warm undertones, resulting in a cooler or more neutral appearance.

In contrast, other options suggest functions that are not part of a toner’s primary purpose. Enhancing shine pertains more to products specifically formulated for that purpose, such as shine serums or glosses. Lightening hair color is usually the function of bleach or other lightening agents rather than a toner. Lastly, adding moisture to dry hair is the domain of conditioners and moisturizing products, not toners. Therefore, the essential role of a toner is to modify the undertone of bleached hair, making option B the correct choice.