Like I said in the Worst Thing Ever post, there is nothing worse than hair color that goes from lighter at the scalp to darker on the ends. One of the main causes of this color catastrophe is contributed to porosity. Porosity is the ability for something to absorb moisture. As an example, a sponge is very porous and a piece of glass is not porous. That’s a basic analogy, but you get the point. Now that we have the definition covered – how does it relate to your hair?
To understand how porosity relates to hair, you may need to know the structure of hair. Here is simple hair composition 101 for you: First, there is the cuticle, the outside layer of the hair shaft which is made up of scale-like cells. Just under the cuticle is the cortex which is what gives strength and elasticity to the hair and because it also contains the melanin (pigment), it gives hair its color too. Finally, in the very center of the hair shaft lies the medulla, which isn’t so important for what we are talking about.
When hair is exposed to the elements–heat styling, chemical services or friction–the cuticle opens. It’s sort of like a pine-cone. When a pine-cone is fresh on the tree it is closed, but when it is exposed to the elements, it opens up. The more the pine-cone is exposed, the more it continues to open. The more we expose the hair cuticle to the elements, the more it opens. The more it opens, the more porous the hair becomes – PHEW! What a lesson.
Why is all of this important (or hopefully, at the very least, interesting) for the at-home colorist? Because understanding porosity can help guarantee that your end result looks salon fabulous! If your hair is to the shoulders or longer, chemically treated or heat-styled daily, there is a good chance you have some porosity issues. Porous hair sucks up color, thus causing the ends to look more matte, opaque or dark than the less porous mid-shaft and root areas. And this is how your roots can look lighter than the ends – the worst thing ever!
Look for my upcoming post called Balance It Out for tips and tricks on how to conquer porosity and achieve balanced hair color from roots to ends!
Did you learn something?
LMK – Jason