Final answer:
Metallic hair colors are also known as permanent haircolors. Permanent hair coloring chemically alters the hair structure by removing natural pigment and adding synthetic color, which doesn't wash out but will eventually fade over time.
Step-by-step explanation:
Metallic hair colors are more commonly known as permanent haircolors. Permanent hair coloring is a chemical process that alters the structure of the hair by removing the natural color and replacing it with synthetic pigments. This process involves three components: an oxidative dye, a coupling agent, and an oxidant. Over time, all pigments wash out of the cuticle, but natural color will remain longer than artificial pigments which fade faster, depending on the molecules and types of dye pigments used.
Permanent haircolors are designed to withstand washing and do not wash out, unlike semi-permanent colors which typically fade after four to six weeks. It's important to note that permanent hair color does not mean that the dye will stay forever, but rather that the hair has been chemically changed until it's cut away. The final result can vary based on the hair's original color and porosity, which means that permanent dyes can create natural-looking variations throughout the hair.