Should you find yourself possessed of the desire to turn your hair from its genetically-determined color to something resembling sun-blanched straw, it is essential that you understand the task that you are about to undertake. A haphazard approach, believe me, will lead you to unmitigated grief and public humiliation. Allow me to offer a guide to hair-bleaching success, based upon my own experiences.
The Decision
Before you begin mixing chemicals like a mad scientist, consider the motivations for your actions. This is not a decision to be taken lightly. You must be sure of your resolve, and aware of the implicit risks.
Bleaching your hair will have drastic social consequences. People tend to look unkindly on those who indulge in radical aesthetic modification, which includes adopting unnatural hair colors. While most such colors inspire thoughts in many people of "FREAK!", bleached blonde invites in addition the labels of "SLUT!", "FAG!", or "EMINEM WANNABE!" Variation and severity depend on age, race and gender.
On a related note, take into account your choice of occupation in the present or near future. A coffee shop barista, for instance, can pass off glaringly blonde hair with relative ease and few repercussions. A tax attorney, on the other hand, may be treading on very thin ice. The same goes for most professional fields, with the possible exception of those involved with high fashion or information technology, etcetera.
There are certain physical consequences to bleaching your hair, foremost of which is severe cortical damage. Breakage, split ends, and frizziness await you and will require constant corrective attention. Also, your hair will lose its ability to hold pigment. Whether you want to add lowlights or try another color entirely, you will enjoy only temporary success. The color will come out over a couple of washings. You will have to wait for your hair to grow back out, in the meantime suffering the embarassment of the reverse-skunk look. Not very appealing.
This is a very serious change. Consider the above, and make your decision. Give yourself time to think about it, and/or sober up. You might thank yourself later.
Preparation
First, buy your product. Regardless of what the various boxed kits at Wal-Mart may tell you, they will not do the job. You need to go to your local salon supply store, most of which sell to the public. In the western United States, the Sally Beauty Supply chain is my personal favorite. Once there, you will probably find a multitude of choices, with various characteristics and results. You can buy straight powdered bleach, or a bleaching kit. I prefer the latter. If at all possible, buy the Wella Wellite Cream Lightener. It comes in a teal box, and is absolutely the best product I have tried, among several. Understand that this guide is written based on the use of this product, and may not produce the desired results with anything else. Next, buy at least 4oz of 40-volume creme developer. The primary ingredient is hydrogen peroxide, and you will mix it with the lightener.
There are some optional supplies you may also want to buy. Almost mandatory is a capsule or bottle of red/gold corrector. The name should explain itself. Another good choice is an anti-itch/burn additive, many of which contain soothing aloe vera. Alternatively, look for pure aloe vera gel at a health food store. Get an application bottle or brush if you don't have one. For the bottle, get at least an 8oz size with volume markings. If you opt for a brush, choose one with a broad edge and a pointed handle, which is handy for dividing hair. You should also buy some rubber/latex gloves and a shower cap. Lastly, it would be a good idea to buy some really good reconstructive conditioner to use after the bleaching. The Ion brand makes a good one.
Do not wash your hair for at least 36 hours before bleaching. This will allow your hair a chance to build up enough oil to protect itself and your poor scalp, which is about to take a beating. Avoid using too much hair product, which might block or otherwise counteract the effects of the chemicals.
Immediately prior to the bleaching, you should gather the following: the above supplies, a suitable container for the bleach, an implement with which to mix the bleach, old ratty clothes, a cape or dispensable towel, a mirror and a chair. Only use things that you don't mind getting bleach on. If you haven't already done so, do your best to recruit a competent assistant. It can be very difficult to do your hair yourself, especially if you have long hair. Next, settle on an acceptable work area and protect any surfaces that you don't want bleached. Adequate lighting, ventilation and horizontal surfaces are important. Finally, move your supplies into this space and get changed.
Execution
Once you have arranged your workspace and changed, you can set yourself to the task. Make sure to put on gloves to avoid contact between the bleach and the skin. First, mix your potion according to the product instructions. You should make at least 8oz to start with, depending on the amount of hair you are working with. Bleaching short hair or new growth will require less, but it is a good idea to have extra at the end for touching up. When mixing, blend or shake the mixture vigorously to eliminate lumpiness and uneven chemical distribution. If you choose to do so, add the red/gold corrector and anti-itch/burn liquid and mix again. If using aloe vera gel, apply sparingly to scalp instead.
With the bleach prepared, sit and cover your upper body with the cape or towel, and get to work. There are three important points: be quick, be thorough, and be methodical. It helps to divide the hair into quadrants and work clockwise around the head. Above all, find an approach that works for you. The tip of a bottle or the handle of an application brush may be used to take quarter-inch rows of hair and turn them over. Apply the bleach liberally starting at the roots and drawing out to the ends, or to the end of dark roots (do not re-bleach already bleached hair as this can result in severe damage). The hair should be reasonably saturated. It can help to agitate the hair after application with the fingertips or brush edge.
Once all the hair to be bleached has been covered, gather it on top of your head and put on a shower cap if you have one. You could also wrap your hair in a towel. This step serves to seal in radiant heat around your head, which facilitates the chemical process. Now, you wait. The length of the wait depends on your individual hair color. Using the Wellite kit, you are probably safe leaving it on for up to an hour and a half or more. Just relax, this is going to hurt but you will be rewarded for your courage. At half hour intervals, check your hair's progress and re-apply to dark spots. As you near the end, the time between checks will decrease. Use your judgement on when it is done. Stopping too soon can lead to disappointing results, and going too long will do major damage. If you reach the aforementioned time limit, stop and plan for another treatment.
Once you are ready, get in the shower and rinse out your hair. Do not use shampoo, your hair is very delicate right now. Be gentle, but be sure to get all of the bleach out. Once you have done this, apply conditioner immediately. Wait a few minutes and rinse again. Get most of the water out and then apply conditioner again. Wrap a towel around your head, with the conditioner still on, and settle in for a quiet night at home. If possible, spend the night in the towel and rinse the conditioner out in the morning.
Now, enjoy the results. Hopefully. I have never had to repeat this process, but it is not impossible that you might. If you do another treatment, do not neglect to do the conditioning routine first. This is important. Most likely, however, you will have achieved the wonderful towheaded look you have always wanted. Be nice to your hair, it has been through a lot. You will find that your previous haircare program will no longer be sufficient. Experiment with different combinations of products until you find what works for you. Diligent and unsparing care will ensure you enjoyment of your bleached-blonde hair for years to come.
As I mentioned, this advice is based on my own extensive experience, not with my own hair but my wife's. Over the past several years, this method has been very effective for her, a natural brunette. I am constantly being complimented by her not-so-cheap hair stylist for the results I have gotten. Now be aware, most hair professionals will give you very different advice than I have. They will say that you will destroy your hair. They may be right, but I am convinced that they only desire to take your money. No offense to hair stylists, whom I generally like very much, this is just my observation.