An all-over glaze or dye isn't the only way to work blue into black hair; Potempa suggests adding a "fun color" -- like steel blue -- to the ends of hair for a supernatural, ombré effect. "Ask your stylist to lighten the ends of your hair to the extreme and then tone them with your favorite blue hue," she recommends. Kylie Jenner models a more literal version of the blue-black trend with midnight blue hair.
