Dying red hair to blonde requires bleaching the hair, then using a quality blonde hair color kit to achieve the desired results. Bleaching can be very damaging to the hair, and the procedure may need to be done more than once, depending on how dark the hair is.
Prior to bleaching, the hair should be as healthy as possible. To achieve healthy hair, refrain from washing when it's not absolutely necessary, deep condition often and regularly trim split ends.
Bleaching the hair requires a bleaching kit, which can be purchased at beauty supply retailers or big box stores. Removing red tones from hair requires the use of a blue bleach. This removes all traces of red or orange tint that can leave hair looking brassy. The lower the developer, the less damage will be done. A 20 developer minimizes damage and does a good job of removing traces of red, if used with a bleach as directed.
Once the hair has been bleached, it is important to use a quality toner to remove the orange and yellow tint that remains on the hair. Follow the package directions for best results.
Once these steps are complete, it is time to color. For best results, pick up a hair color with a separate developer from a reputable beauty supply store rather than an all-in-one color kit. This allows for complete color customization. Follow the directions on the hair color for best results.