Hair coloring is the process of artificially dyeing hair to a different color. It varies according to individual preference of type, color, and method of application. There are many different types of colors available that have varying degrees of permanence.
Permanent
This is the most long-lasting type of hair coloring. With this process, you do not have to worry about going in for frequent touch-ups to maintain the color in the hair. The main agent in permanent hair dyes is ammonia and it penetrates deep into the hair shaft to give a lasting effect.
Then the hydrogen peroxide in it will help in removing the natural hair color and impart the artificial dye. Any new hair growth will be in the color of the dye, although hair growth near the roots will have to be touched up as required.
Demi-permanent
This type is targeted towards those who want permanent dyeing without the involvement of many chemicals. These hair dyes do not contain ammonia and they have low quantities of hydrogen peroxide in them—which is good for people who are allergic to high chemical content.
As the hydrogen peroxide content is less, you cannot use them to color their hair to a lighter shade. You can opt for a shade that is close to the natural hair color or slightly darker. This type is the most commonly used one to cover greys, and it will start fading after 10-25 washes.
Semi-permanent
These dyes do not contain any ammonia or hydrogen peroxide, so they are not likely to damage hair at all. But because of the absence of these two coloring agents, these dyes do not penetrate into the hair shaft and are applied only on the outside of the hair.
There are both natural and synthetic variations to this hair dye. The most popular natural dyes are henna and indigo. These types of dyes can only be used to darken the hair color, and they wash off within 5 to 10 hair washes.
Gradual dyes
These dyes are ones that change the color of hair over time and through a number of applications. For example, you can use gradual dyes to go from grey to darker grey to black. The process happens slowly over regular application so that people can avoid changing their hair color abruptly.
These dyes fade upon shampooing so you have to be consistent to achieve their desired hair color. These dyes don’t contain any harsh chemicals and are generally safe to use unless one has really sensitive skin, in which case a patch-test is recommended.
Temporary
These dyes, similar to semi-permanent colors, do not penetrate the hair shaft and are applied on the surface of the hair. These colors can be washed out after one session of shampooing, although those with thin hair will find that the color stays slightly longer.
These dyes come in a variety of shades, not just natural hair colors but also over-the-top colors like neon pink, blue, gold and the like. Tinting or dipping hair with one of these dyes can be a great way to make a statement. Temporary hair colors are great for experimenting and to have fun without the commitment of permanent dyeing.