Final answer:
Toners are used on pre-lightened hair to achieve pale and delicate colors, typically following the process of bleaching. They adjust the shade of lightened hair to reduce any undesired warm tones, creating a more precise and desired color. Permanent hair coloring involves a chemical change that lasts until the hair is cut, whereas semi-permanent color fades with time.
Step-by-step explanation:
Haircoloring products used on pre-lightened hair to achieve pale and delicate colors are known as toners. Toners are often used after the process of bleaching, which is a permanent change that removes the natural pigment from the hair. Unlike bleaching agents, such as diluted hydrogen peroxide mixed with aqueous ammonia, toners do not lighten hair but instead subdue unwanted brassy or yellow tones in the lightened hair to create a more refined hue.
It's important to understand that permanent hair coloring is a chemical process that alters the structure of the hair until it is cut away. During this coloring process, the natural hair color is removed and synthetic color is added. Semi-permanent hair color cannot lighten hair as bleaching does; it only adds pigment to the outer hair cuticle and will fade over time.