Final answer:
Demi-permanent hair colors utilize low-volume hydrogen peroxide to develop color molecules and assist in the color processing, typically without or with minimal ammonia, thereby causing less damage to the hair than permanent dyes.
Step-by-step explanation:
Demi-permanent hair colors develop their color molecules and aid in the color processing mainly through the use of low-volume hydrogen peroxide combined with other chemicals, usually without ammonia or with a very low amount of it. This type of hair dye contains couplers and an oxidant to create the dye while employing a less aggressive chemical reaction than permanent hair coloring, which means it gradually fades over time without the same degree of damage to the hair's natural structure. The process involves the oxidation of diaminobenzene derivatives resulting in larger dye molecules that are trapped within the hair shaft, thus imparting semi-permanent color.