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.