PSI Indiana Cosmetology Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The developer typically associated with permanent hair color is 20 Volume. This volume of developer contains enough hydrogen peroxide to lift the hair cuticle and allow the dye to penetrate the hair shaft effectively, ensuring long-lasting results. It is commonly used in conjunction with permanent coloring products because it provides a reliable level of lift and coverage for gray hair while maintaining the integrity of the hair.

Using 20 Volume developer allows for a moderate level of lift (about one to two levels), making it ideal for depositing color and achieving desired results without excessive damage. This balance is crucial when working with permanent color, as the goal is to create vibrant and lasting color while preserving the health of the hair.

Higher volumes, such as 30 Volume, provide more lift and are often used for more dramatic changes or to achieve specific effects, but they can also increase the risk of damage if not used properly. Lower volumes, like 10 Volume, are primarily used for deposit-only colors or when there is no significant change in hair color level required. A developer of 50 Volume is rarely used in typical salon settings due to its high strength and potential for significant damage.