What is a common consequence of using an incorrect toner?

Using an incorrect toner can result in a muddy or undesirable hair shade. Toners are specifically designed to adjust the color of hair, neutralize unwanted tones, and enhance the overall appearance. For instance, if a toner is used that does not complement the underlying pigments in the hair, it can create an undesirable result such as brassiness or a dull, muddy color. The selected toner must effectively counterbalance the existing hues to achieve the desired final look. A toner that is not suited to the hair's base color can lead to unexpected variations that are often not flattering, resulting in a less appealing overall appearance.