A hair toning helps to correct or personalise your colour. It is used to add natural or more visible tones after a professional colour treatment. As a result, it enhances the tonality of your hair. How? By creating a professional finished look. In order for toner to work, hair has to be pre-lightened or coloured first. It is most commonly used for shades of blonde hair, but it can be beneficial for brunettes and redheads too.