Bleaching is a chemical process that removes existing pigment, natural or artificial, from hair. Unless your hair is naturally blonde, bleaching will usually go hand in hand with hair coloring, as blonde hair is best suited to hold dye. The lighter the blonde, the more dye it will hold. A typical bleach mixture used to lighten hair combines powdered bleach and liquid creme developer, which activates the bleach; as discussed in the previous section, these are commonly found sold together in typical bleach kits, or separately in beauty supply stores.

Before starting bleaching, hair should be washed, conditioned, dried, and combed. Begin with your materials around you in an open space (possibly ventilated) and plenty of room to work. To begin mixing, put the bleach powder in your plastic container or bowl. Hold it away from your face; most powders are made not to dust, but still be careful not to breathe the stuff in. Put the developer in the bowl a little at a time. Avoid breathing in the fumes from the mixture, as they are quite repulsive. The mixture should be about as thick as yogurt, and smooth with no clumps of powder.

Before applying the bleach to your hair, apply petroleum jelly to your hairline, ears, and back of the neck. Gather the bleach with your brush, and apply. Having someone else apply bleach for you is always a good idea, especially if bleaching your entire head, as trying to cover all the spots when you can't see the back of your head is difficult. Either way, it's important that every section that needs lightening is thoroughly covered. If bleaching large sections, make sure to lift up layers of hair and apply bleach underneath. It's a common newbie mistake to only cover the top layer of hair that is immediately visible. Every piece of hair on your head, even the parts you never see unless you pick up all the underneath layers, should be covered to ensure the best result.

Start at the back of your head or neck and work up. If your roots are darker than the rest of your hair, make sure to start with those; or do them last if they're lighter than the rest of your hair. Work it in with the brush, a comb, or gloved hands. When you think you're done, comb out the hair to help the bleach spread more evenly, then check again for unsaturated spots. If you're bleaching only your roots, let a little bit of the bleach run into your other color; this prevents you from getting a dark ring of unbleached hair around the top of your head. Don't rush, but be aware that hair will start to lighten right away, and the set time for the back of your head will be different than the front. If you have very long hair, you will want to bleach in two separate sessions.

Bleach should be set until your hair is visibly light blonde, but never left on for more than 90 minutes. This is generally enough to go from even the darkest colors to light blonde. No matter what color hair you have, bleach will progressively lighten your hair from black or brown to light brown, light orange red, strawberry blonde. then light blonde. Feasibly, if you're looking to achieve a naturally red color, you should wash out the bleach at this intermediate stage, and have enough lightening to adjust the shade later with dye. When you're satisfied with the lightening, or after 90 minutes (whichever comes first), wash out with shampoo. If you don't have adequate sink space, taking a shower is fine as well.

Highlighting can be done with a highlighting cap. It looks like a regular shower cap with holes in it, and usually comes with a hook. The idea of this is to only hook certain strands through, and put the bleach on top of that to only bleach those strands. you still have to pay attention to pick up layers, otherwise only the top layer gets bleached, and if you pin up your hair, they can't be seen. Hook through as thick of strands as you can. It'll hurt a bit, but it's effective. There's also the foil method, which I find easier. You apply bleach to desired strands manually, then hold them seperate from the rest of the hair by wrapping them in foil, and setting for the same period of time. Regular kitchen foil is fine. I think the foil makes it easier to specify the exact spots and size of strands you want highlighted than the cap. Make sure there's enough bleach on when you wrap them. Don't be afraid to unwrap them and check on the lightening. Try and pin up the wrapped strands to the foil doesn't come off as you move around.

If coloring, hair should be dry right away - wash with shampoo but no conditioner, then blow dry to as dry as your hair can handle so oil doesn't reform. (Sean says the reverse. what to do?)

I've heard a lot of people going crazy with bleach trying to achieve white hair. Bleaching over and over is not only risky, it really won't work. Don't bleach the same hair more than twice in one day, or it will likely become so damaged it'll break off. If it stops lightening, it's done all it can. Just do it once or twice, than just get white toner dye that will make the color more neutral.