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.
Texture
Let'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
Texture plays a very important role in determining what ingredients most likely will or won't work for you. Those blessed with normal texture can use a wide variety of products with decent results. Chemical processes (color, highlights, perms) are usually pretty straight forward with this hair type.
Fine haired gals usually need lighter products, and less slip in their products. We tend to refer to them as "grabby" products because they have little slip (the smoothing quality that aids in detangling) and will make silky strands seem to have more substance. Fine haired ladies can use oils, but they need lighter oil, like Grapeseed, and go light on them. Fine hair is more prone to damage, so care should be taken when using a chemical process on this type of hair. You should (with any type of hair) perform a test application on shed hairs to determine the time you need to get your desired result without frying your hair. This is very important for fine hair because it will most likely process faster than other hair types.
Coarse hair is probably the trickiest texture. It's strong, which is good. But can be very hard to moisturize, and it's usually chronically dry due to an excess of protein in the hair's cortex. Coarse hair also tends to be low-porous because it is very strong, it isn't as prone to the damage of other hair textures. This means that the cuticle is "packed" tightly together, making it difficult for moisture to get in. Coarse hair is quite water resistant, so it seems to take forever to get the hair wet. Coarse hair will usually take longer to process when doing color or other chemical processes. Coarse hair also has a problem with using oils and build-up from products in general (even CG products may build up on the hair, because unlike fine or normal hair, it absorbs very little of the product).
Porosity
Porosity can involve the cuticle simply not laying flat against the cortex naturally (hair that is kinky, and I don't mean "afro textured", I mean hair that has sharp bends along the hair shaft and these can occur in any hair texture, will naturally have some porosity) or hair that has damage for a number of reasons, from brushing or combing too aggressively, to chemical services, being prone to damage because of you hair texture, even the act of wetting your hair can damage it over time. Some products may damage hair, and heat styling is a major culprit.
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.
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.
Porous hair, on the other hand, will readily absorb product. Oils are usually very beneficial for this hair type, because they help coat and seal the hair shaft to prevent the loss of moisture and protein through the "holes" in the cortex. Porous hair doesn't seem as prone to build up as non-porous hair (when using CG products, non-CG products that contain non-water soluble silicones will almost always build up). Porous hair absorbs product VERY well (sometimes TOO well). This can be a problem with gels. Yes, it absorbs the heck out of those, too. Often, when a non-porous individual and a porous individual use the exact same gel, the non-porous individual will report that gel has a very hard hold, while the porous individual reports that is was merely a medium to medium hard hold. This is because the gel will sit on the outside on the hair shaft in non-porous hair and create a harder gel cast, while it absorbs then evaporates on the porous hair. I personally deal with this by using my Sweet Curls Flax Seed Defining Gel on very wet hair (this helps seal in moisture, set the clumps that disappear in my hair if it starts to dry, and encourage curl). Then I scrunch out excess water and gel with a microfiber towel, wait 10-20 minutes for my hair to start to dry and the gel to start to set up, and apply either more Flax Seed Gel, Flax Seed Gel mixed with a hard gel, or just hard hold gel. This allows the hair to absorb product (and at this point, my leave-in, and the Defining Gel both had oils to help seal the hair) and some of it to evaporate as the hair dries, but still gives me good definition and clumps (which I do not get if I just wait put product on drier hair) and the second application will sit on the outside of the hair shaft providing more crunch like it is supposed to.
Porous hair also tends to need a lot of protein. Protein in the cortex is lost when washing (or swimming) through the "holes". Moisture is also lost through these holes over time. Porous hair will often notice that right after washing their hair feels great. But by the end of the day, or the next morning, their hair feels dry again. By using regular protein treatments, these holes get temporarily "patched" reducing porosity for a time. I myself like to use a combination of smaller more conditioning proteins (amino acids) and the larger proteins (hydrolyzed proteins) to replace protein in the cortex AND to patch the holes in the cuticle.
Elasticity
Elasticity is usually indicative of the protein/moisture balance in the hair. Hair that is not elastic is often prone to breakage resulting that "halo" of short (often frizzy looking) hairs that tend to stick out/up around the crown. Non elastic hair needs more moisture.
Hair that is too elastic will stretch out of shape, waves and curls may appear limp, not as curly/wavy as usual, and with less volume. Hair that is too elastic needs more protein.
Hair that stretches, then returns to it's natural shape, is hair that has a good protein/moisture balance. The aim here is to keep that balance!
I highly recommend getting a hair analysis done. https://www.etsy.com/shop/GoosefootPrints is a great place to get this done. There are others that do them, Live Free Live Curly has one, but I think that they just do the same as GoosefootPrints mini physical analysis. (I can't be sure on this. But I believe they just do the self-tests that have listed on the website to determine properties). Komaza Care has an in depth analysis. I hear it's great, but the wait is long and it's pretty expensive. GoosfootPrints does an in depth scientific analysis (not the mini analysis) and it's quite affordable. I know this is a side job for her, so she may get backed up at times, but I DO know she knows hair, very well.
Now, here are some at home self test. These can give a general idea of your hair's properties, but they are far from an in depth analysis.
Texture: this one is fairly easy, it will give you a pretty good idea of your hairs' texture. However, sometimes it can be hard to determine, as your hair may fall into an in - between texture, such as medium fine, medium course, etc. You may also have more then one texture. You may have textures ranging from very fine, to some course hairs.
Hold hair up to a light. If it hard to see, wispy, maybe even a bit translucent, it's probably in the fine range of texture.
If it easily seen, seems very thick and study, maybe even wiry, it's most likely in the coarse range.
If it's easily seen, but does not seem wiry or very very thick, it's most likely normal.
You may also want to check out http://science-yhairblog.blogspot.com/2012/06/is-your-hair-fine-medium-or-coarse-how.html. This is the same lady who provides the hair analysis through GoosefootPrints.
Porosity: check out this link. I really have nothing to add to her great post on porosity tests!
Elasticity: again, Sceince-y Hairblog has already covered this, and I have nothing to add to her great post! http://science-yhairblog.blogspot.com/2013/07/diy-hair-analysis.html
I think you can see why if you are in the market for a scientific hair analysis, this lady is the one you should go to! (and no, she isn't paying me to say that!)
Conclusion
This is why I say "we don't have one size fits all hair". Because we really don't! It's unfair and confusing to lump curl types into a hair care routine with products that may or may not work for them. Just because your hair curls or waves a certain amount, has nothing at all to do with your hair properties and how your products will work for you. Even just guesstimating your properties will go a long way in helping you decide how to care for your hair, and what products (and products ingredients) will most likely work best for you.