Porosity and Elasticity

When your hair grows out of your head, it is born perfect.  The hair's cuticle lies flat and smooth.  When your hair gets damaged, the cuticle begins to open up.  Hair with a closed cuticle is non porous.  Hair with a cuticle that is open, or missing chunks is porous.  Some hair is naturally susceptible to damage.  Some hair will become porous from sun damage, wind damage, etc.  But...perming, coloring, flat irons, etc. are common causes of porous hair.

Non porous hair (Low porosity)-  Is hard to get wet.  Water runs off it like off a ducks back.  Non porous hair takes a long time to dry (8 hours-ish).  It is hard to get water into the closed cuticle, but once the water is in there, it is locked in tight.  In other words, it is hard to wet and takes a long time to dry.  It will sometimes squeak when you run your hands over dry hair.  Non porous hair is resistant to color, but once is is colored, it won't fade.  It is also resistant to perming or chemical straitening.  These solutions will have to be left on the hair longer for them to be effectively penetrate the closed cuticle.  Low porosity hair is healthy hair.  It is shiny, especially if it is dark.  Hair products seem to sit on top of non porous hair and does not soak in.

Normal porosity hair- Is relatively easy to deal with.  It takes perms and color treatments predictably.  If you always get the color on the box, this is a sign you are normal porosity.  It dries at an average rate (3-4 hours-ish).

Porous hair (High porosity)- Is easy to get wet.  Porous hair dries quickly (1-2 hours-ish) without product.  With conditioner and gel, it may take a long time to dry.  Porous hair soaks up hair products like a sponge.  Porous hair will dye darker then the box (if dying hair a darker color then your natural color).  However, the color will fade quickly.  Perms will take curlier then expected, but then relax quite a bit.  Porous hair is damaged hair, but that doesn't necessarily mean that your were doing terrible things to your hair.  Some hair is just naturally susceptible to damage or has natural kinks that make it porous.  Porous hair tends to be dull.

I should note that the drying times are my guestimations, no actual science involved.  Drying times are based on hair without conditioner or gel.  Products can greatly increase the drying time. Drying times will also be affected by length, thickness, humidity, temperature, etc.

If you read around on NC.com, you may come across the float test.  IMHO, this test is notoriously inaccurate.  I'd call it phoney bologna.  My porous hair literally floated for days.

The Natural Haven:  Junk Science- Hair Porosity Tests/Float or Sink

My porous hair will get wet from the steam when sitting in a hot bath.   My hair will dry in an hour or two without product, but will take all day to dry when I used a heavy conditioner and lots of gel.  I need lots of conditioner and gel for my hair because it soaks it up.  When I dyed my hair darker with a permanent dye, it would dye much darker then the woman on the box.  Then the color would fall right out of my hair.  All the color would be completely gone in three weeks.  When I used to perm my hair (darn 80's) I would look like a poodle the first few days, and then my hair would relax to a normal perm.  The first day people would always say "Oh, you got your hair permed.  It looks....um...nice?"  Then I'd say "Don't worry.  It won't look like this in a few days."  The right hair products have gone a long way to help me with my porous hair.

For more info, I love this curl chemist article.  All of her articles are interesting. You may also like reading The Natural Haven:  Porosity:  Definition and Causes 



ELASTICTY
Take a hair from you head and firmly grasp each end.  Stretch it gently. 

If it breaks, it has low elasticity.

If is stretches up to 1/3 of its length and returns to its normal shape, it has normal elasticity.  Good for you.

If it streeeeeeeetches and does not return to its original shape, it is overly elastic.

Overly elastic hair is a sign of over conditioning (too much moisture). Low elasticity is often a sign of dry hair, but can have more complex causes.  You can do the elasticity test on dry or wet hair.  You may find it easier to take a few shed hairs and sort of twist them together and then pull on the whole wad of hair.  This is an easier way to test my super fine hair.  It is very hard to grasp just one of my hairs.

How to Classify Your Hair with the FIA system

The Fia info was copied from this site.  The info in purple was added by me.

Fia's Hairtyping System

FIRST CLASSIFIER:

The straight ones 
1a - stick straight
1b - straight but with a slight body wave, just enough to add some volume, doesn't look wavy
1c - straight with body wave and one or two visible S-waves (e.g. nape of neck or temples)

The wavy ones
2a - loose, stretched out S-waves throughout the hair  Beachy waves, rock star waves
2b - shorter, more distinct S-waves (similar to waves from braiding damp hair) Princess Hair
2c - distinct S-waves and the odd spiral curl forming here and there A mix of waves and curls and some pieces that have a mix of S and C shapes.  On NC.com this is often referred to as "Wurly" hair.

3) The curly ones 
3a - big, loose spiral curls  Like a telephone cord.  (Anyone else old enough to know what that is?)
3b - bouncy ringlets  Ringlets the size of a pinky finger.
3c - tight corkscrews  Ringlets the size of a pencil or straw.

4) The really curly ones  Common among African Americans.
4a - tightly coiled S-curls 
4b - tightly coiled hair bending in sharp angles (Z-pattern)

SECOND CLASSIFIER
What (most of) your individual strands look like

F - Fine
Thin strands that sometimes are almost translucent when held up to the light. Shed strands can be hard to see even against a contrasting background. Similar to hair found on many people of Scandinavian descent.

You can also try rolling a strand between your thumb and index finger. Fine hair is difficult to feel or it feels like an ultra-fine strand of silk

M - Medium
Strands are neither fine nor coarse. Similar to hair found on many Caucasians.

You can also try rolling a strand between your thumb and index finger. Medium hair feels like a cotton thread. You can feel it, but it isn't stiff or rough. It is neither fine or coarse.

C - Coarse
Thick strands that where shed strands usually are easily identified against most backgrounds. Similar to hair found on many people of Asian or native American descent.

You can also try rolling a strand between your thumb and index finger. Coarse hair feels hard and wiry. As you roll it back and forth, you may actually hear it.


Science-y Hair Blog explains how you can measure your hair will a ruler to tell the texture.  See this link.

THIRD CLASSIFIER
Your overall volume of hair

Put your hair in a ponytail with as much hair as possible in it. Don't bother with the way it looks - the goal is to have most/all of your hair in there. If it means it sits smack dab on top of your head, put it there.

Measure the circumference of the ponytail. If you have bangs and/or you can't get all of your hair in there adjust according to how much of your hair you have measured.

To measure the circumference - take a piece of string, or a soft tape measure (the kind used by dressmakers). Wrap the string or tape measure <i>around</i> your ponytail - just below the elastic you have in to hold the ponytail together. Read the corresponding number from the tape measure, or hold the string at the length you've measured and use a ruler to determine how much it is. The number given is the circumference of your ponytail.

i - thin (less than 2 inches/5 centimeters)
ii - normal (between 2-4 inches or 5-10 centimeters)
iii - thick (more than 4 inches/10 centimeters)

NC.com link with photos of different curl patterns.

Your curl pattern may not fit neatly into only one category.  It is common to see a mix of curl patterns on one head.  This is especially true for wavies.  Some hair just doesn't fit any description.  
Figuring out your hair texture can be tricky as well.  Your hair stylist should  be able to tell you your hair's texture (Kinky or dry hair has been known to throw some stylists.  See below).  If you compare your hair with your friend's hair, this should help you with figuring out your hair's texture.  
Live Curly Live Free has a service where you send in your hair and they tell you your hair's texture, porosity, and elasticity.  The hair analysis I would recommend for a similar price is GoosefootPrints on ETSY.  At GoosefootPrints you get your hair analysis, pictures of your hair under a microscope, and a helpful document that helps you interpret your hair analysis results.  See my sample GoosefootPrints Analysis post. 
If your hair is dry and therefore has a rough feel, you may mistakenly think your hair is coarser then it actually is.  If your hair has some kinky pieces mixed in, this can also make you assess your hair as coarser then it actually is.  Any ethnicity may have kinky hair.  I'm as pale as they come and 40% of my hair has kinks (my GoosefootPrints hair analysis told me this).  This link explains the difference between kinky hair and curly hair with helpful illustrations.  Hair is kinky because of the way it twists (see illustration in link). Another type of kinky hair is where the hair shaft narrows and widens.  I have both of these types of kinks in my hair.