Arizona Cosmetology Practice Exam

The term "developer" in hair coloring specifically refers to the peroxide used to activate the color. When hair color is applied, the developer is mixed with the hair dye to create a chemical reaction that allows the color to penetrate the hair shaft. The developer contains hydrogen peroxide, which serves to open the hair cuticle so that the color can effectively internalize, resulting in a longer-lasting and more vibrant shade.

The other options do not accurately describe the role of developer in hair coloring. A tool used for styling hair does not involve chemical interaction with dyes, while a type of conditioner focuses on moisturizing and improving the overall health of the hair rather than coloring it. Similarly, a type of hair treatment pertains to processes aimed at enhancing hair condition rather than altering its color. Therefore, understanding that developer is key to the chemical process of hair dye application enhances one's comprehension of hair coloring techniques.