Paraphenylenediamine—more commonly known as PPD—is a chemical substance that is commonly found in permanent hair color and other dyes. PPD in hair color is most often used in dark shades; hair color companies use PPD pervasively because it provides long-lasting hair color that has a natural look. PPD hair dye is used in both salon and at-home color because it is an effective ingredient in coloring dark hair. PPD is also commonly used in temporary tattoos, dark colored cosmetics, and even in textile dyes and printing inks.