Hair is a filamentous biomaterial (made of long chains of proteins, interactions with biological systems), that grows from follicles found in the dermis (middle layer) of the skin. It is composed mostly of keratin, which is a fibrous structural protein.
The entire human body except the palms of hands and soles of feet are covered in follicles that produce hair.
Each strand of hair is composed of three layers: The cuticle, medulla and cortex.
The cuticle is the outermost layer. It is composed of hard shingle-like cells that overlap each other. It is formed from dead cells that have turned into scales. It's purpose is to protect the inner layers and give the hair strength. The shape the cuticle is in, determines how healthy your hair is. Healthy, shiny hair has a cuticle that is smoothed down. In damaged hair, the scales are raised up. You can smooth the cuticle down by using mild heat (like a towel wrapped around your head after you get out of the shower) or acidic based hair products (which is why a lot of hair products contain citric acid, etc.) Products high in Alkaline do completely the opposite, and they raise the cuticle.
The next layer, in the middle, is the cortex, which makes up most of the hair. Melanin, which are color pigments, are located here in the cortex. They determine the color of the fiber of the hair, based on how many there are and what types they are. The shape of the hair follicle determines the shape of the cortex, which there determines whether hair is straight, wavy, or curly. The cortex also holds water, and is packed with keratin protein. The process of coloring, perm / straighteners, or other styling all takes place in the cortex. The innermost layer is called the medulla, although some people (with fine hair) do not have a medulla. It's purpose is still unknown.
Hair color is generally classified by numbers 1-10. Level 1 is generally black, while level 10 is generally blonde.
All natural occurring hair colors are combined of percentages of the three primary colors: Red, Yellow and Blue. The two main chemicals found in permanent hair color are hydrogen peroxide, and ammonia (this is why color is damaging to your hair). Ammonia works by separating the cuticle scales. Peroxide helps oxidize pigments. When the hair color is penetrating into the cortex, it creates new pigment molecules, which are too big to come out of the cortex. This is why it is hard to take color out, once you put it in.
Bleaching your hair is a similar process. The peroxide softens and lifts the cuticle and then the bleach (lightener) disperse the color molecules that are in the cortex.
There are different level of peroxide. 5V and 10V (V = volume) are deposit only. You would use them to deposit a darker color (like black) and they work by only lifting the cuticle a tiny bit. 20V lifts up to 2 levels and deposits color. This is the most common peroxide used. 30V lifts up to 3 levels and 40V lifts up to 4 levels. You will not see 40V being used often. It is usually only used with high-lift blondes and bleach, but it is very damaging on your hair and can burn the scalp, if used incorrectly.
Now, back to primary colors …
The three primary colors, like I said before, are red, blue and yellow. The three secondary colors are orange (red + yellow), green (blue + yellow) and violet (blue + red). Look at the way the color wheel is set up, for it is done this way on purpose. The color directly across from a color, is its complimentary color. Complimentary colors can either intensify or neutralize each other. For instance, when you bleach your hair, it usually ends up a pale yellow tone. To take away the yellow, you tone your hair with a violet based toner to turn it platinum-blonde. This is why a lot of "blonde" shampoos are purple. If your hair is orange, you should tone it with a blue based (ash) toner.
Toners are basically pigment to tone your hair after bleaching it. I highly recommend toning hair after bleaching it, because it looks more finished. There are so many different varieties of toners. You can tone hair ash blonde, platinum blonde, neutral, strawberry blonde, etc.
Let's say your hair is bleached but you decide you want to color it back to brown. You have to re-pigment hair first. If you do not, the color will turn out really ashy / greyish and faded looking. To re-pigment (fill) the hair, you want to use reddish / goldish colors that are one level lighter than the desired color. I used Paul Mitchell color and there are different formulas you can use depending on your target level. For PM, you would mix equal parts of the formula with 10V developer, and apply to damp hair. You process for 10 minutes and then apply the target color over the re-pigmentation formula (except the target formula is cool / neutral, you would wipe off the re-pigmentation formula). Process the whole thing for 35 additional minutes.
Next, I will get into the different types of colors: Permanent colors can lift you hair up to 3 levels, generally and should last quite a while. High-lifts will lift the hair about 4 levels. Demi-permanent colors last about 4-6 weeks and will wash out ever, leaving no roots. Temporary colors generally coat the hair shaft, without penetrating into the cortex, therefore not needing developer. If done right, these should even last a few weeks. The little old ladies use a color rinse a lot, which is a temporary color that will just wash out next time they wash their hair.
A very important thing to know about color, that most people do not know, is that
COLOR WILL NEVER LIFT COLOR
This basically means that if your hair is dark brown, and you want to lift it to a light brown, you have to bleach your hair before it will take the color you want. I hear customers talk about this at work ALL THE TIME. They are confused because they tried to color their own hair lighter and but it just turned darker. Now consider everything I have taught you so far. If your hair already has dark color molecules in the cortex, and you put another color on top of it, all you are doing is depositing more color molecules into your cortex, since the reason it is darker. Color will lift virgin hair, but not hair that is already colored.
Now I will tell you how perms and straighteners work. You always clarify before doing a perm, since that will help get build-up and medication out of the hair. While the hair is wet, you roll it into rollers (same width as the result curl will be). You then apply perm solution to each perm-rod and let it process. Perm solution is generally made of ammonium thioglycolate. The solution breaks down the disulfide bonds in your hair (which are the proteins that give your hair shape.) After you have processed, you rinse the perm solution out and then apply neutralizer. Neutralizer rebuilds the disulfide bonds in the new shape of the perm rod. Voila! Now you have curly hair! Straighteners typically do the same thing, except they make your hair straight instead of curly.
Well, I hope you learned something new and interesting about hair! There are so many other cool things to learn and I will write about them a later day!
Have you been to beauty school? I always love to hear new things, so if you would like to add anything to this article, please comment.