You may be wondering what makes acidic haircolor unique. Acidic demi-permanent haircolor offers gentle processing on the hair for outstanding condition and shine benefits. All of Redken's Shades EQ gloss shades are acidic and provide an extensive array of shade options. With its gentle acidic formula, Shades EQ is not only perfect for achieving any customized color you want, but it also provides shine-enhancing benefits for healthy, beautiful hair color.