Hair developer is a type of cream or liquid chemical used in the hair coloring, highlighting, or lightening process. Its primary purpose is to activate the color process by opening the cuticles so that the chemical can penetrate the hair shaft. Choosing a developer to lighten your hair depends entirely on your natural color. Lower volumes of 10 and 20 are used for naturally lighter hair, and 30-volume developers are typically used on dark hair. Never use any developer over 30—the strength of the chemical at this volume can be too strong and burn if it touches your scalp.

Things You'll Need

Apply a deep conditioner to your hair one day prior to lightening to help minimize damage that may occur from the required chemicals.

Put on plastic gloves. In a small plastic bowl, combine the pre-measured packages of 30-volume developer with the hair bleach from the lightening kit and mix with the brush. If products are purchased separately, combine 1 ounce 30-volume developer with 1 ounce bleach powder.

Start with the bottom layer of hair that you wish to lighten. Use several hair clips to pin all but the bottom layer of hair to the top of your head.

Grab a 2-inch section of hair from the bottom layer. Brush the developer and bleach mix onto the entire section, from root to tip. Brush all sides of the section for even coverage. Repeat with remaining sections on the bottom layer. Then, let down another layer of hair and repeat the process until you’ve applied the developer and bleach mix onto all the hair you wish to lighten. Work quickly because 30-volume developer lightens hair fast. Leave the product in for no longer than 30 minutes.

When your hair has reached your desired shade of lightness, thoroughly rinse out the developer and bleach and use a gentle shampoo to remove the chemicals.

If your hair is naturally dark, it can become orange if you try to lighten it too much. You can fix this with a toner. Work the toner through the hair from root to tip with your fingers. Allow it to set for 10 minutes, then rinse.