Major color transformations can take a toll on your client's hair, which is why maintaining its integrity is one of your main priorities during the harsh process. Even though it took celebrity stylist George Papanikolas (who works with celebs like Khloe Kardashian and Hailey Baldwin), eight hours to take model Lydia Hearst from a rich red back to her natural blonde, he managed to protect her locks from major breakage. "It's up to the colorist to make a judgment call about how light the hair can go when doing transformations such as this," notes George. Find out…