To use this Pastel Iris hair dye, first, if you want the most vibrant color, bleach your hair to a pale blonde or platinum shade. Make sure the bleaching is even, especially if you have dark or previously dyed hair. Before applying the dye all over, do a strand test because the color in the bottle may look different on your hair. Once you're ready, apply the dye as you normally would for semi - permanent dyes. Since it's non - damaging and doesn't need a developer, the process is straightforward. After application, follow the typical after - care for semi - permanent hair dyes. Keep in mind that the pre - dye hair color will affect the final shade, with platinum hair showing the color best. And because it's 100% vegan and cruelty - free, you can use it with a clear conscience.