Coloring Your Hair

Hair Colors
Coloring your hair is perhaps the quickest and most dramatic way to change your look. It is also an excuse to go out and buy a new wardrobe of clothes, because you'll find that what suited you as a brunette looks rather drab on a new blonde.
There are two types of hair dyes: permanent and semi-permanent, with variations of each.
A) Permanent Tints:
Must be mixed with hydrogen peroxide to lift hair color. The peroxide opens the hair cuticle so that the tint can penetrate the cortex and form the color. The higher the level of peroxide, the quicker and lighter the result.
B) Semi-Permanent Colors:
They don't actually lift the color - you can either vary the tone within your natural highlights or go darker. Quasi-color contains ethanolamine and 3% peroxide which slightly opens the cuticle. This means that the color can last up to 20 washes and will softly fade as you shampoo, causing no regrowth problem.
C) Semi-Permanent Vegetable Colors:
Contain only vegetable extracts and natural ingredients, so no color is stripped from your hair. It is similar to henna but it doesn't coat the hair (adds shine though). This color sits on the hair's surface and will wash out after about 8 shampoos.
Different coloring methods suit different hair styles, so get some expert advice when deciding which one to go for...
Skin Tone: Your new hair color should complement your skin tone. Light-skinned people don't look good with very dark hair because it draws color out of their skin. Dark, tanned skin doesn't look great when mixed with a one-tone blonde, but four or five blonde, chestnut or honey tones look fabulous.
BLONDE:
If you would love to be blonde, talk the process through with your colorist (or stylist) before you go for it. It should be relatively painless on virgin dark brown hair, but if your hair has been permanently tinted then the process will become a long saga.
Never attempt this kind of dye job on your own for the first time.
RED:
Red is the ultimate sexy shade, for color that cries out for attention. Hair holds on to red-toned pigments well, so going copper-top can be easy for most people.
But be warned - if you are blonde you will usually have to go two or three shades darker than your natural color to achieve a rich red (brunette), and it's not easy to reverse it.
BROWN:
Brunette is always a safe choice as it suits nearly every girl in town. Varying the shade with highlights can achieve a huge range of looks. From chocolate brown and bronze shades to honey or dark blonde, combinations of natural tones gives incredible shine as darker-pigmented tints add condition to your hair.
BLACK:
This is by far the easiest color to accomplish because the molecules in black tints are larger and will cover all hair types very effectively. Caution is needed when using black as it only tends to look good on people with darker and olive skin tones. it's great for getting the goth look, but definitely not for your granny.

source:http://free-beauty-tips.glam.com/coloringhair.html