There are a number of hair coloring techniques that can be used to create various effects. The basic categories of hair color products include permanent dyes, semi-permanent dyes, and products that can be washed out of the hair with just a shampoo. There are two general options with permanent hair coloring techniques.
Hair can either have color permanently taken away or permanently added. If a brunette, for example, goes to the salon with the intention of becoming a blond, she will have her hair stripped of its natural color so that it can lighten to a blond shade. If a woman with gray hair, on the other hand, goes to the salon in hopes of coloring her hair a dark brown color, then she will have color permanently added to her hair, which will cover the natural, light color of the hair.
A semi-permanent hair color product will usually wash out of the hair within a few weeks or a few months, depending on how frequently the hair is shampooed. This kind of product usually only adds color to the hair instead of stripping color away. This is because stripping color from the hair is a permanent process. For this reason, semi-permanent hair coloring techniques can only darken or change the color tone of the natural hair.
Some people who prefer to use natural products choose to color their hair with henna or vegetable-based dyes. The permanence of these kinds of hair coloring techniques varies greatly from product to product. The end result also depends on the initial color of the hair prior to the application of the product.
In addition to all-over color, some people also choose to color just sections of their hair. The most common example is the use of highlights. Highlights are created by stripping a certain amount of color from a few strands of hair all over the head. This techniques makes the hair look more multi-dimensional and can also be used to frame the face.
Sometimes, to create edgier looks, stylists use hair coloring techniques to color large sections of the hair in different shades or tones. Sometimes, for example, the entire underside of the hair will be colored with a dark color such as brown or dark red, and the top of the hair will be lighter, like a blond color. This means that the hair color will look entirely different when it is allowed to fall about the shoulders than when it is styled in an up do.