When dying your hair, it is important to add an oxidizing agent such as a developer. The developer contains hydrogen peroxide which opens the hair's cuticle to allow the dye to penetrate. When purchasing a hair developer, you see bottles labeled in quantities of 10 (10, 20, 30, 40 and 50). The higher the number, the stronger the developer. Clairoxide 40 is a powerful developer that should be used with discretion, since it works through hair very quickly.
Wear latex gloves to protect your hands from the chemicals and dyes.
Pour and measure 4 oz. of the Clairoxide developer into the plastic applicator bottle.
Measure and squeeze 3 oz. of the colorant gel into the bottle. Fasten the top of the applicator bottle. Cover the opening of the bottle with your fingertip and turn it away from you. Shake the bottle until the two are completely mixed.
Brush through your hair to release any tangles or knots. Fasten a towel around your shoulders to protect your skin and clothing.
Work the mixture from the ends of your hair to the roots. Saturate your hair fully.
Wait 30 to 40 minutes for the color and developer to process in your hair. Rinse the mixture out with lukewarm water and condition your hair with a rich conditioner to seal in the color and moisture.
If you have never dyed your hair, it is advised to a salon to have it professionally done. Clairoxide 40 is a very stronger developer that quickly works on your hair, and can be damaging if left in for too long.