Celebrity hair colorist and creator of the latest hair color trend, Rita Hazan has launched this season’s must-have hair product. Rita’s new Pop Color Temporary Color Spray ($18) is a collection of pink, purple and blue spray-on hair color inspired by a nationwide trend that Rita originally debuted on her client, Katy Perry. Combining Hazan’s signature color formulas with her proprietary aerosol spray technology, Pop Color is as fun to apply as it is to wear, said the company. It does not alter...