In the 1930s an artist named Robert Dorr discovered that all colors can be separated into two color spectrums based on their undertones - blue-based or yellow-based. He found that people also contained these two primary undertones. Over the next four decades, he researched and refined his color system, which the fashion, cosmetics, textile, paint, and furniture industries have used. This is the original color system, and the one I use with my clients, because of how accurate, easy, and fun it is.