Today, I'd like to explore hair properties. What they are, how you can find them out, and why you should care.
The hair shaft is made of layers. The outermost layer is the cuticle. The cuticle looks a bit like a shingled roof. These "shingles" are, when laying flat, water repellant. Shampoos, hot water, alkaline hair products can raise these "shingles" which can let moisture/protein treatments in, but also if left open, can let them OUT. The cuticle protects the inner layer, the cortex, which is made up of keratin protein bundles and this is where water (moisture) is stored. The cortex also contain the melanin which determines hair color, and the shape of the follicle determines the shape of the cortex. A round follicle will result in a round hair fiber that is pretty straight. Oval or irregular shaped follicles result in irregular shaped fibers which waves and curls. The cortex is what makes up the bulk of the hair fiber. There is also the innermost layer, which in finer textures may be missing, the medulla.
Hair properties are measurements of the characteristics of your hair. I don't mean how much your hair curls (or doesn't). Sure, it's fun to know that your a 2b, or a 3C or whatever, but when it comes to caring for your hair and choosing products it means nothing. Honestly, one of the things that bugs me most is when people lump a certain curl type together and say "This is how you should care for your wavy/curly/kinky hair." Because it's impossible to say that all 2C waves behave alike. They don't. Let's say Lady A has 2C waves. So does Lady B. Lady A has fine hair with low porosity and normal elasticity. Lady B has medium textured hair, porous, very elastic. You give them both a light non oily condish (often recommended for wavies, because it's believed wavy hair gets weighed down too easily). You will get two different results. While Lady A may like that it did not leave oil on top of her non porous hair, she may not get enough moisture using this condish alone. Lady B however, may feel like her hair feels good, moisturized and light and bouncy, at first. But because there are no oils to help seal in the moisture, she may start to feel like she has straw on top her head by day's end.
TextureLet's first take a look at texture. By this I mean the general average circumference of each individual hair strand. I say the average circumference because many of us can have more than one texture on our heads. Hair can be fine, medium (or normal), or course.
Fine hair is most often likened to silk. If you hold a strand up to the light, it may be hard to see. You might not even feel it between your fingers. It can be flyaway, delicate, and/or limp. It's easy to curl or style, but the curl or style falls out quickly.
Medium (normal) hair can be easily seen when held up to the light, but isn't very thick. It usually curls or styles easily and can usually keep that style. It feels smooth (when undamaged and properly moisturized) but not like the silk of fine hair. I guess a good comparison would be silk vs. satin. They both feel smooth but the silk has a delicate quality while the satin feels smooth but is more sturdy. Medium texture is called normal because it is the most common texture.
Coarse hair will easily be seen when held up to the light. It will appear very thick. It seems resistant to bending, therefor resistant to styling, and can be easily felt between your fingers. Some have described it as "wirey" feeling/acting.
Why texture matters
Hair that is non-porous may not like oils in their products. They tend to sit on the outside of the hair shaft. For normal textured hair, they leave an oily look/feel for awhile and slowly absorb over time. For course haired individuals, they most often do not absorb at all (or very little). Non-porous hair may experience build up (and yes, even CG products can build up! Cationic ingredients bond to the negatively charged hair. And because the hair shaft is already smooth, without any damaged spots for the positively charged Cationic ingredients to bond to, they will just coat the hair strand, and unless they are removed regularly they will continue to build up) more often than porous hair, because again, products do not absorb as easily. Often non-porous (and particularly coarse, non-porous hair) will have trouble with getting hair to a moisturized state. It is naturally quite water repellent. Using heat will help open up the cuticle layer to allow water and conditioner in. Frequent deep treatments with heat will go a long way in helping get moisture into the cortex. The combination of heat and allowing the water and conditioner time to penetrate allows the cortex to absorb as much moisture as possible.
Non-porous hair will not like (usually) protein in every day products. The exception is fine to very fine hair. This hair type may need more protein because they just do not have as much protein in the cortex to help waves and curls support themselves, and to protect against damage.