Colorado Cosmetology Written Practice Exam

The correct answer is progressive hair color, which is specifically formulated with metal salts designed to create a gradual change in hair color through a buildup effect. This type of color reacts with the natural pigment in the hair and continues to develop over time, requiring regular applications to achieve the desired shade. The oxidation process occurs when the hair is exposed to air, enhancing the color gradually with each use.

Permanent hair color, on the other hand, requires a chemical reaction that permanently alters the hair's structure and does not typically involve the gradual buildup characteristic of progressive hair colors. Semi-permanent hair color lasts longer than temporary options but does not gradually change color in the same way, as it essentially deposits color molecules onto the hair's surface without the involvement of metal salts or the same oxidative process. Temporary hair color, while it can change the hair's appearance for a short time, simply coats the hair shaft and does not lead to a long-term change or buildup effect.