Christophe Robin Temporary Colour Gel Christophe Robin Temporary Colour Gel ($35) is an at-home, root-covering hair colour option that requires no mixing and just blends any greys into the colour of the rest of your hair and then slowly and evenly washes out each time hair is shampooed. Image Source: sephora.com Christophe Robin Temporary Colour Gel $35 from sephora.com Buy Now