Bleaching hair is a process that alters the pigmentation of hair follicles, causing it to turn a lighter shade. There are two ways to get bleach blonde hair back to its natural shade - allow it to grow out, or dye it back. Some people use a combination of these methods - dying the hair gradually until it reaches a shade closest to their natural colour so that the roots and the bleached portions resemble each other as closely as possible. This can be done at a salon, but is also able to be done cheaply and effectively in the comforts of your own home.
Shampoo your hair. Do not use any conditioner, as this will prevent the pigments in the dye from taking hold in the hair follicles. If you have sensitive skin or a sensitive scalp, wait approximately 12 to 24 hours after shampooing to continue. This will allow your body's natural oils to build up and protect your scalp.
Apply a thin coating of petroleum jelly around your scalp line. A thin coating across your forehead, the back of your neck, around your ears and even the tips of your ears allows you to easily remove any dye that may leak onto skin during the colouring process.
Put on a pair of disposable latex or rubber gloves. These will prevent colour from reaching your hands, fingernails, and skin as you dye your hair.
Mix and prepare the hair dye. According to L'Oreal hair colour specialist Christophe Robin, it isn't wise to go more than one or two shades darker than your current shade per dying session. Choose a colour based upon those guidelines. The process of restoring hair colour to its natural state is a gradual one.
Drape an old towel over your shoulders. Change into old clothing that you wouldn't mind being ruined if a hair dye accident occurred.
Apply the dye to your hair, starting at the tips first and working your way to the roots. Allow the dye to soak into your hair for the time period specified by the manufacturer.
Rinse your hair under cool water. Cool water closes hair follicles, allowing more pigment to stay within the hair shaft. Rinse until the water runs clear.
Use a moisturising conditioner made for colour treated hair to repair some of the damage that the dying process has inflicted upon your tresses. Rinse the conditioner. Some colour may come with the conditioner. This is normal. Rinse until the water runs clear.
Towel dry your hair, Dispose of any gloves, caps, hair dye bottles and debris left from the dying process. Wash towels and clothing that were exposed to dye.
If your hair needs more dying to return it to its natural shade, repeat the dying process two to six weeks later.
The darker your natural shade of hair is, the longer it will take to dye from bleach blonde shades. Be patient. Different hair colours have different undertones. "Ash" colours are on the cooler shade of the colour spectrum, whereas "golden" colours have reddish undertones. Neutral colours fall somewhere in between. Take this into account when choosing your hair dye.
Hair dye doesn't just leave its mark on hair - it also colours walls, sinks, bathtubs, carpet, curtains, couches and more. Remove spills or accidents while they are still fresh to avoid a harder to clean up stain later. Many home hair dying kits do not provide the same highlighting effects that natural hair has. If this is desired, speak with a professional hair stylist.