To understand proper processing times, it helps to first look at how permanent hair color works. How Ion Color Brilliance Permanent Hair Color Works In this comprehensive guide, we’ll explain everything you need to know about how long to leave Ion Color Brilliance permanent crème hair color on your hair. Under-processing can lead to uneven results or faded color, while over-processing risks damage. But to get the best results from these permanent hair dyes, it’s important to leave the color on your hair for the right amount of processing time.
