So you tried to lighten your hair from a Level 3 brown to a level 9 light blond with a box hair color. Didn't work right? Basic rule of color is you can not "lift" or lighten more then 2 levels. When going  2-3 levels higher than your natural hair color, you must first destroy some of the natural pigment by bleaching or a less harsh word decolorizing, removing natural and artificial pigment in your hair. This should really be done by a professional colorist.

How hair bleach works:
Bleach and other hair lighteners are alkaline products. Alkaline causes the hair to soften, swell and expand.

While lightening, the hair goes through seven stages: black, brown, red, red-gold, gold, yellow, then pale yellow. This happens because the bleach is oxidizing, causing the cortex (where the pigment is located) to "open" and the pigments inside are diffused and broken down which causes color loss.

Attempting a bleach job at home is highly unrecommended. There are several problems that can occur such as burning, hair loss, and basically a Bad hair color job. Your best bet is to spend the extra money and see a professional who specializes in high lift coloring.

Before you even attempt this, read about about Tones and levels and lifting in hair color 101. Now for a safe warning before you start: These home kits do contain bleach and peroxide, the same tools we use at the salon to highlight hair.
However, since these are dangerous chemicals, their strength is not nearly as high as professional products. Thus leaving you with one thing to remember, they CANNOT lighten your hair very much.

Yes, if you have dark brown hair and want warm, honey highlights (level 6 to maybe 8)  these will work. And yes, if you have blonde hair and want light highlights, these should work for you. But if your hair is dark brown, and you want blonde, level 8 or 9 highlights, you will only get nice brassy orange colored strings of hair. And if you are red, natural or artificial, you will get lighter, pink toned or orange highlights. So use with caution and do a test strand underneath your hair to see what color you will get before doing your entire head of hair.

Using Artificial Hair color to lighten your Artificial Hair Color at home:
Ok, Remember the golden rule of hair color? Artificial hair color cannot lighten artificial hair color. Technically, it can, but only a half a shade which isn't very noticeable. And when speaking about Home hair color kits, it's a definite no lift rule. So what does this mean? You cannot lighten your artificial hair color with another hair color at home. EX: you have colored your hair dark brown, or black. and now you want that beautiful, cool toned medium brown.....
:
This is what you'll end up with: Beautiful brown roots and midshaft down to the ends will still be that dark brown shade you wanted to get rid of. The only way to accomplish the color you want is to remove some of the old artificial hair color by bleaching midshaft down and then applying a new hair color. This is nearly impossible to do yourself without messing your hair color up bad. At the salon, this is called a double process hair coloring or a corrective hair color job.

I hate to be the bearer of bad news, it's just home hair color products and salon hair color products are truly different. During schooling, stylists become chemists. And we're taught how to use these chemicals with caution and in the correct way. The FDA regulates drugstore hair color products and keeps their ingredients at such a low, SAFE level that they become almost ineffective. This isn't a case of name brands are better but the items are the same. The two product lines are totally different.


reprinted from styles101.com