Pink hair is usually the result of applying a red shade of haircolor to hair that is blonde. Unfortunately, fixing this problem presents a challenge to even the most experienced professional stylists. While there are some types of color correction that can be done at home, pink is definitely a problem which requires a professional's help.
The main problem with pink is that it is virtually impossible to bleach out of the hair. Therefore, the only solution is to either apply a toner or to color the hair darker in order to cover the unwanted pink tones. A toner, which is an acid-based semi-permanent shade of color, works be eliminating unwanted tones from the hair. This is done by use of the color wheel, a tool most of us are familiar with from high school art class. To neutralize an unwanted tone from the hair, a hairstylist will apply a toner in the shade that is opposite of the unwanted color on the color wheel.
Since pink contains mostly red pigment, the opposite of red is needed to fix the problem. This, of course, is green. Now, before you shudder at the thought of having your hair dyed green, remember that only a small amount of green in a color formulation is necessary. Most shades of ash brown or ash blonde, for example, contain green pigment. If you wish to keep your color on the lighter side, have a professional apply a light shade of ash blonde toner.
Although toners are great tools used to fix color problems, sometimes they just aren't strong enough. If the hair still has a pink hint to it, even after toning, it may be necessary to repeat the toning process or choose a darker color in order to cover the pink. Fortunately, pink can almost always be fixed by applying a neutral shade of brown to the hair.
If your goal is to have red hair, this can be done by applying a red shade of permanent color. However, it may take a few applications before the red is deep enough. Coloring blonde hair red is much like trying to paint a white wall with one coat of red paint. You simply aren't going to get great coverage with just one coat. Depending on the shade of red which is desired, it may be necessary for a stylist to apply a filler to the hair. Filling the hair is essentially staining the hair in order to provide better coverage. Think of a filler as a primer. Just as painting a white wall a darker color will require a primer, coloring blonde hair a darker color will require a filler.
Because of the risk of damage to the hair, it is always a good idea to leave color correction in the hands of a trained professional.