Thursday, June 7, 2012

Is Your Hair Fine, Medium, or Coarse? How to Measure

Is your hair fine, medium, or coarse? It's not always easy to tell. Healthy hair and dry, environmentally-stressed hair may feel and look very different. You may think your hair is coarse (wide) when it really has some fiber twists and bends (kinking) or is "medium." Dry hair is often described as "coarse" feeling because it feels rough.©Science-y Hair Blog 2013

Measuring is the best way to find out what the dimension of anything actually is. Hair is measured in microns. There are 1000 microns in one millimeter. ©Science-y Hair Blog 2013

Hair Diameter Categories:©Science-y Hair Blog 2013
Fine hair: Less than 60 microns (16 or more hairs per millimeter)
Medium hair: 60-80 microns (12 to 16 hairs per millimeter)
Coarse or wide hair: 80 microns or greater (fewer than 12 hairs per millimeter)

To do this test, you need about 20 hairs which you have shed, and a metric ruler. 

How to choose your sample:
We're assuming that hairs you've shed while washing or on your clothes are a "random sample" meaning they are hairs from all over your head and therefore there is a good chance that these represent your hair in general. If you take hairs from only one part of your head, you may get a inaccurate result. For example, the hair on the top of my head tends to be finer (40-60 microns) than the hair near the nape of my neck (60-80 microns). I want both in my hair sample. Unless I want to measure them separately! If you want to measure different areas separately, collect hairs from those areas and keep them in a bag or jar with a label until you have enough to use.

1) Dip the hairs in clean water to rinse them and make them pliable. No knots! Cut them to a manageable length if they are quite long.
2) Line up 10 of the hairs in a drop of water or a drop of hair gel (the water will help them stay in place and prevent them from bending or curling). Pack them as closely as possible without overlapping - use a straight pin or toothpick to press them together. Make sure you count how many hairs you are using. You're going to pack them more tightly than you probably think is correct. Just don't let them overlap. If you do not press them very tightly together, you'll get an estimate which is too large. You'll create a very solid little sheath of hair. There should be no gaps or air spaces. If your hairs are very curly, weight them at each end and gently pull them straight. If you have tightly-curled hair with many kinks, apply coconut oil or another oil to the hairs to make them pliable.
3) Place the ruler gently over the swath of hairs and see how many are fitting into a millimeter. Put the ruler down on the hairs, don't hold it above them. If you can add more, add them, make sure you keep track of how many you added.©Science-y Hair Blog 2013

Then refer back to the list. 
  • 15-16 hairs or more pack into a millimeter: Your hair is fine.
  • 10-12 pack into a millimeter and you are pressing them tightly: Your hair is medium.
  • 10 hairs pack together within a millimeter: Your hair is either medium and has kinks that prevent close packing, or it is coarse.
  • Fine hair is silky when healthy. It bends easily, it is dented easily by ponytail holders and hair pins. It is easily flattened by weight of water, oils and conditioners or or other hairs. Think of milkweed down or little-kid hair. 
  • Medium hair has a little more structure. It resists bending a little more than fine hair. Medium hairs are easier to see individually and feel between the fingers. 
  • Coarse hair resists bending. It feels strong between the fingers and is quite visible, even against a similar-colored background.

This picture if of fine hair. I packed 15-16 hairs into one millimeter. You can see it wet, but there's a photograph of the hair dry too because it photographed better. I know these hairs are about 60 microns in diameter, so I kept packing even when it seemed that 12 was enough.
Hairs laid out in water - the space between the
smaller marks is one millimeter.

Oops. I made a gap when I put the ruler down.
This will give me an inaccurate result. But the
photo is in better focus.

Same hairs, photographed dry. They spread out a bit
when I put the ruler down - that's why
I suggest using water to hold them in place.

These are the same hairs, all spread out. It's hard to tell from
looking at them like this that so many will pack into
one millimeter.
A word about kinks in hair. Anybody can have kinking in their hair strands. This may be subtle widening and narrowing of the hair shaft. It may be a subtle twist in a similar motion to wringing the water out of a wet cloth. Or it may be lots of tiny bends. You may feel these when you run your fingers over a strand of hair as bumps or roughness, but you may or may not be able to see them. 

Is this method completely accurate? If you pack those little hairs in tightly and also take into consideration the way your hair behaves as well - it should give you a good estimate. You can always have hair which is in-between. Measurements are only as good as the technique of the person doing the measuring. If you feel you got the wrong result, try it again, try it with the hairs dry instead of wet, use a hand lens (magnifying glass) to see your work.

The trickiest part of this method is to get the hairs to stay in place.

Why do I suggest this tricky method? This is a Science-based blog. In science, measurement is critical. You can't really have facts without measurement of some sort. And when we measure, we must absolutely have accurate references because all measurements are relative. For example weight is relative to a standard pound or kilogram. I call this the "sanctity of reference materials." If your reference materials are not chosen with accuracy and effort, all your facts and conclusions will be wrong. If I tell you that a toothbrush bristle is "x" number of microns and a silk or wool or cotton thread is "x" number of microns, so just compare your hair to these things - which toothbrush, thread and so on am I referring to? Is there a global standard? No. All there is, is extreme variability. Measuring is at the heart of science. And it is not always easy.©Science-y Hair Blog 2013

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