Why coloring hair
Because it is the one thing that can dramatically change our
appearance If we don't like the way we look! Also, it is quite fun to change it.
I do agree that most of the time we look the best with our natural color. There
are few reasons that why we want to dye hair,
(1) We want to lighten our hair more than three shades,
(2) We have dark hair
and want to dye to make them light or ,
(3) We have natural light brown or blonde hair and want to dye it,
(4) We are re trying to fix a problem,
(5) We have light hair and want to make it darker.
(6). Many people think that gray is the first sign of aging
and the end of his youth, so they go for hair coloring.
Natural hair dyes
Hair dye is one of the oldest
known beauty preparations, and was used by ancient cultures in many parts of
the world. Records of ancient Egyptians, Greeks, Hebrews, Persians, Chinese,
and early Hindu peoples all mention the use of hair colorings. Early hair dyes
were made from plants, metallic compounds, or a mixture of the two. Rock alum,
quicklime, and wood ash were used for bleaching hair in Roman times, and herbal
preparations included mullein, birch bark, saffron, myrrh, and turmeric. Henna
was known in many parts of the world; it produces a reddish dye.
Many different plant extracts were used for hair
dye in Europe and Asia before the
advent of modern dyes. Indigo, known primarily as a fabric dye, could be
combined with henna to make light brown to black shades of hair dye. An extract
of the flowers of the chamomile plant was long used to lighten hair, and this
is still used in many modern hair preparations. The bark, leaves, or nutshells
of many trees were used for hair dyes. Wood from the brazilwood tree yielded
brown hair dyes, and another hair dye known in antiquity as fustic was
derived from a tree similar to the mulberry. Other dyes were produced from
walnut leaves or nut husks, and from the galls, a species of oak trees. Some of
these plant-derived dyes were mixed with metals such as copper and iron, to
produce more lasting or richer shades.
Synthetic hair colors or dyes
In general, hair dyes include
1.Dyes,
The dye chemicals are usually
amino compounds, and show up on hair dye ingredient lists with such names as
4-amino-2-hydroxytoluene and m-Aminophenol. Metal oxides, such as titanium
dioxide and iron oxide, are often used as pigments as well.
2.Modifiers,
Modifiers stabilize the dye
pigments or otherwise act to modify the shade. The modifiers may bring out
color tones, such as green or purple, which complement the dye pigment. One
commonly used modifier is resorcinol, though there are many others.
3.Antioxidents,
Antioxidants protect the dye from oxidizing with air. Most
commonly used is sodium sulfite.
4.Alkalizers,
Alkalizers are added to change the pH of the dye formula,
because the dyes work best in a highly alkaline composition. Ammonium hydroxide
is a common alkalizer.
5.soaps, .ammonia, wetting agents,
fragrance, and a variety of other chemicals used in small amounts that impart
special qualities to hair (such as softening the texture) or give a desired
action to the dye (such as making it more or less permanent).
6.Developer
The developer is most often based on hydrogen peroxide, with
the addition of small amounts of other chemicals depending on the manufacturer.
Temporary
Hair Dye
Temporary
or semi-permanent haircolors may deposit acidic dyes onto the outside of the
hair shaft or may consist of small pigment molecules that can slip inside the
hair shaft, using a small amount of peroxide or none at all. In some cases, a
collection of several colorant molecules enter the hair to form a larger
complex inside the hair shaft. Shampooing will eventually dislodge temporary
hair color. These products don't contain ammonia, meaning the hair shaft isn't
opened up during processing and the hair's natural color is retained once the
product washes out.
Semi-Permanent
Hair Dye
This
product adds color without changing natural color dramatically. The hair color
contains tiny color molecules that enter the hair's cuticle, or outer layer,
and go into your hair's cortex. They don't interact with your natural pigments.
And since the molecules are small, they eventually exit the hair shaft after
several shampoos, leaving the hair as it was before treatment.
Permanent
Hair Dye
Permanent Hair Dye molecules enter all the way into
the cortex, where they react and expand to a size that cannot be washed out. These
dyes acts to lighten the hair's natural pigment to form a new base and then to
add a new permanent color.
Structure of Human hair
Hair is made of strong elastic strands of protein called
keratin and in chemical terms is composed of oxygen, iron, nitrogen, hydrogen,
sulphur, carbon and phosphorus.
Each hair is constructed in three different layers: the
cuticle, the cortex and the medulla.
The cuticle is the outermost layer of the hair which provides protection
to the inner cortex layer. Improper care
and frequent use of harsh chemicals on hair damage the cuticle.
The cortex is the second layer. .
The cortex is composed of fibres twisted together like a rope. It is the cortex
which gives the hair its colour. The presence of the four natural pigments
black, brown, yellow and red are logged in the cortex in varying proportions,
and the air spaces in the cortex determine the colour and shade of hair.
Lastly, the medulla is the unimportant innermost layer which
is composed of soft keratin..
How hair colors work
The outer layer of the hair shaft,(cuticle) must be opened
before permanent color can be deposited into the hair. Once the cuticle is
open, the dye reacts with the inner portion of the hair, the cortex, to deposit
or remove the color.
Most permanent hair colors use a two-step process (usually
occurring simultaneously)
- First
removes the original color of the hair
- Second
deposits a new color.
Ammonia is the
alkaline chemical that opens the cuticle and allows the hair color to penetrate
the cortex of the hair. It also acts as a catalyst when the permanent hair
color comes together with the peroxide.
The developer( peroxide) removes pre-existing color. Peroxide
breaks chemical bonds in hair, releasing sulfur, which accounts for the
characteristic odor of hair color. As the melanin is decolorized, a new
permanent color is bonded to the hair cortex. Various types of alcohols and
conditioners may also be present in hair color. The conditioners close the
cuticle after coloring to seal in and protect the new color.
Health risk and hair colors
Use of
hair dye has been linked to allergic reactions, respiratory disorders and even cancer. Harmful ingredients used in hair color and hair dyes ,Hair
dyes contain heavy metals that can be harmful. Ingredients in hair dyes are toxic
and cause irritation to the eyes, skin and mucous membranes to hypersensitive
people.
- Para-phenylenediamine
and tetrahydro-6-nitroquinoxaline, both have shown to damage
genetic material and cause cancer in animals. Allergic reactions from PPD
are known to cause facial and neck swelling. Inhalation is likely to bring
about coughing, sneezing and shortness of breath, and respiratory problems
in extreme cases. Skin contact with PPD may cause rashes and eye contact
irritation, redness and pain.
- Coal tar, a known carcinogen
is used in hair colors and dyes as it creates brighter and more lasting
colors than other organic vegetable dyes.
- Formaldehyde is a preservative
linked to cancer, developmental and reproductive toxicity and more.
- DMDM Hydantoin, another
preservative is a known immune system toxin (and has been restricted for
use in cosmetics in Japan).
- Eugenol is a fragrance
ingredient that’s associated with cancer, immuno toxicity, neuro toxicity
and allergies
- Ammonia exposure to
high levels of ammonia can cause irritation and allergy, hair loss
problems and scalp dermatitis.
- Hydrogen peroxide Hydrogen
peroxide bleaches your hair and thus damages it. But the extent of the
damage will depend on its level of concentration..
Further readings
