hair dye

Hair colouring products generally fall into four categories: temporary, semipermanent, deposit only/demi, and permanent. All these hair colour products, except for temporary colour, require a patch test before application to determine if the client is allergic to the product.

"Hair lightening," often referred to as "bleaching" or "decolorizing," is a chemical process involving the diffusion of the natural colour pigment or artificial colour from the hair. This process is central to both permanent hair colour and hair lighteners.

All permanent haircolour 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 colour.

Temporary Hair Colour

The pigment molecules in temporary hair colour are large and, therefore, do not penetrate the cuticle layer, allowing only a coating action that may be removed by shampooing. An example of use of temporary hair colour is for Halloween costumes.

Acid dyes are used to coat on the surface of hair, since acid dyes have a low affinity to hair, thus can be removed after a shampoo.

Temporary hair colour is available in various product forms including rinses, shampoos, gels, and others. This type of hair colour is typically used to give brighter, more vibrant shades or colours such as orange or red, that may be difficult to achieve with semi-permanent and permanent hair colour. This phenomenon is due to the fact that temporary hair colourants do not penetrate the hair shaft itself. Instead, these dyes remain adsorbed (closely adherent) to the follicle and can be easily removed with a single shampooing. However, even temporary hair colouring agents can persist if the user's hair is excessively dry or damaged, conditions that allow for migration of the dye from the exterior to the interior of the follicle. While temporary hair colour 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 dye.

Semipermanent

Formulated to deposit colour on the hair shaft without lightening it. This formula has smaller molecules than those of temporary tinting formulas, and is therefore able to penetrate the hair shaft. It also lasts longer than temporary hair colour, keeping intact up to 15-24 shampoos.

The American Board of Certified Haircolourists and most major manufacturers of hair colour now say one should colour the new growth area with a permanent colour to cover gray and touch up or refresh the ends and length of the hair with a compatible shade of semipermanent colour to protect the condition of the hair.

Most hair colour manufacturers offer a semipermanent hair colour tube and a permanent hair colour tube within their product line. However, lately, some hair colour manufacturers like Compagnia Del Colore from Italy have come up with a very ingenious and cost-efficient solution for hair colourists. By using an activator or 7 Volume Peroxide (2.1% H2O2) you can now use the same permanent hair colour tube and convert it into a semipermanent hair colour tube.

Permanent

This is mixed with developer and remains in the hair shaft until new growth of hair occurs. It's used to match, lighten, and cover gray hair. Permanent hair colour generally contains ammonia, oxidative tints, and peroxide. The allergic reaction that comes from hair dye is generally one of sensitization to p-phenylenediamine (PPD). The reaction will most likely occur each time one dyes one's hair and will probably get worse each time. The sensitization from the ingredients in hair colour can extend to sensitization of other products of same or similar composition, including but not limited to the dye used in textiles, sunscreen, rubber, and/or certain medications.

Henna is a deposit-only hair colour whose active component, lawsone, binds to keratin and is therefore permanent. Henna may be removed with mineral oil; however, it is considered "permanent" because it does not wash out with shampoos or rinses. It is often mixed with other plant dyes, such as indigo, turmeric, and senna, to change the colour. Allergy to henna is much rarer than allergy to permanent hair colours. It is also considered a conditioning treatment.

Using a plant-based colour, specifically henna, can cause problems later when trying to do a permanent wave (perm) and other permanent hair colour. Discoloration can occur on hair that has been previously tinted with henna; hennaed hair typically cannot be curled. Breakage could also be an issue.

Special Effects

Special effects include highlighting and vivid, unusual hair colours such as green or fuchsia. Highlighting can range from temporary to permanent, using the techniques listed above and a special application process. The techniques required to apply highlighting can be difficult for an individual to perform upon him/herself. One can create looks that range from subtle highlights acquired during a day at the beach, to more dramatic looks, such as bold, chunky highlights.

The more exotic, bright dyes typically contain only tint, and have no developer. These are typically sold in punk-themed stores (such as comic book and music stores), but are rarely available at commercial hair dressers. Colours range from blood red to seafoam green. Many shades are blacklight reactive. Individuals with darker hair (medium brown to black) are advised to use a bleaching kit prior to tint application for the full effect of the colour. Some people with fair hair may benefit from prior bleaching as well, as the yellow undertones of blonde hair can make blue dye look green. These dyes are less permanent, and tend to "bleed" onto other fabric even when dry. Users should anticipate staining of light-colored pillows for a week or so after application.

Social Stigma

In many conservative areas, dyeing one's hair a colour that does not fall within the range of natural shades may not be considered socially acceptable outside of certain circles (subcultures), such as punk, emo, or goth. In many business environments, a strict professional dress code is imposed. As most of the people who work and make hiring decisions in these places consider extremely vivid hair colours to represent a lack of professionality (respect for authority or 'the rules'), someone who has dyed his or her hair an unnatural shade could risk being fired. Additionally, he or she could have a difficult time getting a new job, especially one which requires contact with a customer. Make-up, nail decoration, and clothing choices are also similarly stigmatized in conservative societies.

Further, in societies where pleasure in ones own personal appearance is repressed, the act of dyeing one's hair at all can lead to a lesser degree of social stigma, as a certain amount of 'snobbery' may be perceived by displaying ones natural colour. "This is my natural colour" is seen as an extremely positive, almost boastful, statement to make about one's appearance. There can also be an implication that to expend the time and money necessary in order to change one's hair colour is indicative of unseemly vanity, or low self-esteem.

Social stigma may also be attached to natural hair colours. For example, brunettes are said to be the best cashiers, because they are known as honest. The three main European hair colours - blonde, brunette, and red - fall into common American stereotypes: blondes as glamourous/desirable or dumb, brunettes as classy/sophisticated or boring, redheads as eccentric or sexy/seductive or irascibly tempered. People have often been known to dye their hair to fit the stereotype. These stigmas span continents, as well as history.

Problems Related to Colouring Hair

When coloring one's hair it is always advisable to visit a professional hair colourist as there are many mistakes a person could make, as well as some serious consequences. The following are some of the problems that may occur as a result of applying hair colour:

• Different color outcome compared to what was expected.
• Breakage of hair stands.
• Loss of hair.
• Dry scalp.

Notable People Who Use Hair Colouring

• Brian Giles, Right Fielder for the San Diego Padres Baseball Team
• Dennis Rodman, former professional basketball player
• Christina Aguilera, American pop singer

See also

• Human physical appearance
• Haircut

External links

• How Stuff Works "How Hair Colouring Works"
• Professional Hair Colouring Tips and Chemistry of Hair Colour
• Professional Hair Colour Results at Home
• How to Get the Colour You Want - Tips for Your Visit to the Colourist
• Directions punk hair dye
• Hair Colour Expert Mags answers your Hair Colour questions"