What is the purpose of using a toner on highlighted hair?

Using a toner on highlighted hair primarily serves the purpose of neutralizing unwanted tones. When hair is lightened or highlighted, the bleaching process can sometimes lead to brassiness or overly warm hues, such as yellow or orange tones. A toner is specifically designed to counteract these unwanted shades, allowing for a more balanced, cool, or neutral color that enhances the overall appearance of the highlights.

Toners contain color pigments that can adjust the tone of the hair, making it appear more vibrant and intentional. For instance, a purple toner is commonly used to cancel out yellow tones, while a blue toner can help to neutralize orange hues. This corrective action is crucial for achieving the desired hair color from highlights, ensuring that the hair looks polished and well-maintained.

The other mentioned options serve different purposes. Deepening the color would generally involve a different coloring technique rather than toning. Moisturizing the hair is important for maintaining hair health but is not a primary function of toner. Increasing shine is often associated with other haircare products, such as oils or serums, which provide a gloss but do not address color correction like a toner does.