"Your natural hair color first determines where to start when you're choosing your desired shade," says celebrity colorist Sharon Dorram, who has worked with Julia Roberts, Kate Hudson, and Nicole Kidman. People with warmer base tones, like Emma Stone, who is a natural blond, can take on different colors than someone with a cooler starting hue. Ask your hairstylist, who will be more attuned to identifying nuanced tones.

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