Iowa Cosmetology Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

Purple shampoo is specifically formulated to neutralize brassy tones in blonde hair due to the color theory associated with the color wheel. In color theory, purple is opposite yellow on the color wheel. Therefore, using purple shampoo helps offset and cancel out any unwanted yellow or brassy hues that can develop in blonde or light-colored hair.

The pigments in purple shampoo work by depositing a small amount of color onto the hair, which can enhance the coolness of blonde shades and create a more balanced, luminous appearance. This is especially beneficial for those who have lightened their hair, as it helps maintain a fresh look longer between salon visits.

Other options do not effectively address the issue. A black dye would darken the hair and eliminate blonde tones rather than correcting brassiness. Bleach is used to lighten hair and is not suitable for neutralizing unwanted tones. Similarly, red color would enhance warmth, further intensifying brassiness instead of neutralizing it.