Monday, March 9, 2009

Types of hair color

Hair coloring products are typically categorized based on the length of time they effect the colored hair. The four most common classifications are 'temporary', 'semi-permanent', 'demi-permanent' (sometimes called 'deposit only) and permanent.

Temporary hair color

The pigment molecules in temporary hair color are large and, therefore, do not penetrate the cuticle layer, allowing only a coating action that may be removed by shampooing.

Acid dyes are used to coat the surface of hair, since acid dyes have a low affinity to hair, thus can be removed after a shampoo. The penetration and color strength of temporary hair color can usually be improved by applying a bleaching prior to the application of the hair color.

Temporary hair color is available in various product forms including rinses, shampoos, gels, sprays, foams and others. This type of hair color is typically used to give brighter, more vibrant shades or colors such as orange or red, that may be difficult to achieve with semi-permanent and permanent hair color. Temporary color is also used by some teens for events at school and Halloween. This phenomenon is because temporary hair colorants do not penetrate the hair shaft itself. Instead, these color particles remain adsorbed (closely adherent) to the hair shaft and can be easily removed with a single shampooing. However, even temporary hair coloring agents can persist if the user's hair is excessively dry or damaged, conditions that allow for migration of the pigments from the exterior to the interior of the hair shaft. While temporary hair color products hold a lesser market than semi-permanent and permanent agents, they have value in that they can be easily and quickly removed without bleaching or application of a different coloring product.

Semipermanent hair color

Formulated to deposit color on the hair shaft without lightening it. This formula has smaller molecules than those of temporary tinting formulas, and is therefore able to partially penetrate the hair shaft. It has no developer, but may be used with heat for deeper penetration. It also lasts longer than temporary hair color, keeping mostly intact up to 4-5 shampoos. They are great for hair that is damaged and fragile. Semi hair color has no Ammonia.

'Demi Permanent' hair color

Companies like Compagnia Del Colore from Italy have found a way to change the color pigment molecules to be smaller than that of semi permanent hair color but still larger than permanent hair color molecules. This is done by mixing permanent hair color with low volume (usually a 7 volume developer) that blows off the ammonia from the permanent tube and deposits color molecules only into the hair shaft. A demi is gentler than permanent color used whenever you want to deposit color without lifting the natural pigment but with the penetration being more than semi permanent color and less than permanent, the results last longer than semi but shorter than permanent hair color. Since they are more gentle than permanent hair color, they are great for tint-backs and colorpriming. They are also great for toning pre-lightened hair. Because there is no lifting of natural hair color, they are not as effective on dark hair, due to the over-powering color already existing in the hair.

Semi permanent hair color should be used with caution. For many of these kinds of tints, especially the darker tones, the 'semi' aspect is less active; the coloring is much more on the 'permanent' side than the temporary. For example, when coloring your hair with a black 'semi-permanent' dye that should last for roughly 28 shampoos, you should expect the color to last longer and fade more slowly, regardless of what the box may or may not disclose.

Permanent color

All "permanent" haircolor products and lighteners contain both a developer, or oxidizing agent, and an alkalizing ingredient as part of their ammonia or an ammonia substitute. The purpose of this is to:

* raise the cuticle of the hair fiber so the tint can penetrate,
* facilitate the formation of tints within the hair fiber,
* bring about the lightening action of peroxide.

When the tint containing the alkalizing ingredient is combined with the developer (usually hydrogen peroxide), the peroxide becomes alkaline and diffuses through the hair fiber, entering the cortex, where the melanin is located. The lightening occurs when the alkaline peroxide breaks up the melanin and replaces it with new color.

Permanent Color is the best choice for grey hair coverage. It has an oxidizing colorant that also uses ammonia and peroxide to lift and deposit the new color, going deep into the hair shaft. The use of ammonia opens the cuticle of the hair to allow the color pigments to penetrate deep into the hair shaft.

When coloring your hair with a permanent tint, you should first remember the fact that it's permanent. It sounds simple, but this color will not fade or become less vibrant if it's doing its job. Your natural hair color will reappear when your roots begin to grow, and you should expect to have to tint it more than once to maintain your new color. If you want to get rid of the added color, you will either have to remove the color with a stripping process (depending on the color of the tint) or color it back to its natural color. Either way, permanent hair color is more difficult to maintain, and to get rid of.

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