Final answer:
Lowlighting is the process of making select pieces of hair darker, in contrast to highlighting, which lightens hair. It involves oxidation dye components like an intermediate, a coupler, and an oxidant, and it permanently alters hair's structure.
Step-by-step explanation:
Hair Coloring Techniques
The process of picking up select pieces of hair and making them darker is known as lowlighting. This technique is different from highlighting, which involves lightening pieces of hair. During the lowlighting process, a hairdresser will typically select strands of hair and apply a darker color. This dark color often consists of an oxidation dye, including an intermediate such as 1,4-diaminobenzene or 2,5-diaminotoluene, a coupler agent, and an oxidant. The mechanism includes oxidation of the intermediate to a quinone state, reaction with a coupler (e.g., red, yellow-green, or blue couplers), and then further oxidation to create the desired hair color.
Permanent hair coloring permanently alters the structure of hair until it is cut away, despite the synthetic color potentially fading over time. Semi-permanent hair colors do not lighten the hair and can only deposit color. In contrast, chemical lighteners such as bleach are used for lightening hair and are considered permanent as they remove the natural pigment. Regular hair growth and loss cycles, as well as factors like age and genetics, influence natural hair color changes over time.