When working with hair, you must first study the basics. I know things like underlying pigment, head shapes and definitions of hair texture might have your eyes rolling in the back of your head, but remember that you can't jump to the top of the stairs, you must take each step. With that inspirational introduction, we bring you, the definitions of texture, porosity, and elasticity!
A person's hair texture can be broken down into three categories of fine, medium or coarse.
The type of texture is determined by how the hair grows out of the follicle. If your hair is thick and curly, then your follicle shape will resemble a large oval. If it is fine and curly then the follicle will be a thinner, smaller oval. Straight hair grows out of a circular follicle, and so on. You can refer to the chart above to get a visual of how the shape and size of the hair follicle affect texture. Another word that is used when describing texture, is density. The density is determined by how thick the hair strand is. The larger the hair follicle, the thicker the strand. For example, if someone has fine, wavy hair, then their hair follicle will be small and oval.
Porosity refers to the hair's ability to retain moisture. The cuticle layer of the hair acts much like a sponge. As the cuticle gets damaged, it is less able to retain moisture and starts to lose its protective capabilities.
Porosity is tricky because if the hair is very porous, it will absorb a lot of moisture, it just won't hold onto it. This is something to remember when coloring hair. If you are working with a client who has damaged, porous hair, then beware when formulating and toning, as the hair is much more likely to suck up the color and sometimes vary the results.
If the cuticle is very porous, it needs to be repaired with protein and moisture treatments so the hair can hold onto moisture, which feeds and protects the hair.
If you take a single strand of hair, stretch it and then it bounces back to its original state without buckling or breaking, then your hair has good elasticity (and you've just done what's called an elasticity test!). If the hair snaps, then you have poor elasticity. The state of your hair's elasticity is determined by the hydrogen bonds in your hair and how soft and pliable they are based on their water intake. For example, no matter how damaged your hair is, it will always have more elasticity when it's wet. Having good hair elasticity is an indicator that your system is well balanced and that your hair is receiving adequate moisture and protein.