What's in a Name?

 

The yarn on the left is Brassard 2/16 cotton, the yarn on the right is a 'mystery' yarn labelled 16/2 cotton.

There is much discussion on what those numbers mean.  Many people say that the order of the numbers is immaterial, that they are identical.

What the photo above, taken with my digital microscope, shows is that they are not exactly the same quality of yarn.  

Even though they both have approximately the same number of yards per pound (6720 yards) it is quite clear that the blue/green one is thicker than the rust and the rust is much more tightly twisted.

And yet - they ARE both cotton, they ARE both the same (nominal) yards per pound.  The difference is that the rust has been spun out of longer staple fibres, which have been combed so that they are parallel and then plied much more tightly than the blue/green, which has been spun from carded fibres, or even from a loose fibre mass equivalent to a carded preparation (called open end spun).

You can also see that the rust yarn has somewhat shorter bits sticking out loose while the blue/grey has longer bits of fibre sticking out.

What is the effect of the two different preparations in spinning and the actual spinning?

The rust is stronger than the blue/green and will behave as warp quite nicely.  The blue/green is weaker and much happier as weft.

The blue/green will be more absorbent than the rust because the blue/green is loftier and has more air or gaps in it's structure so it will be easier for the cotton to absorb the water.

The blue/green will also shed more lint than the rust.  The blue/green is coming up in my stash very soon and when I begin weaving with it again, I will make sure that I have my filter fan running to filter some of the lint out of the air.  That will keep it out of my lungs, and hopefully reduce the lint getting into the rest of the house, too.

Just because something is the same 'number' as another yarn doesn't mean it is equal in characteristics.

As we move more into using metric sizing, we need to be aware of the actual method of spinning and look at yarns more deeply.  We can't just assume that because they have the same number of yards per pound they are the same.

These yarns also have the same number of yards per pound.  Again, look at the difference in thickness.  The yarn on the left is Tencel - a regenerated cellulose (rayon) where the fibre has been broken down into a viscous solution then run through a spinneret.  The fibres can be very long and shiny.  The yarn on the right is cotton.  While both may have been spun with the same fibre prep, the density of the Tencel, the long silky fibres are creating a yarn quite different from the cotton.  Both are given the 2/8 designation (or 8/2 because some people think it doesn't matter which order they are used in) but they will behave differently.  While it is true the Tencel has the same number of yards per pound, it is slippery and thinner than the cotton with the same number of yards per pound.  Generally a thinner, slippery-er yarn needs to be more epi than the thicker one.

When I first began weaving, I was told the 8/2 designation was equivalent to a 'woolen' type of preparation while the 2/8 designation was equivalent to a 'worsted' type of preparation.  That doesn't seem to be being taught now, but interestingly, I notice that Jaggerspun, a very American company that spins worsted yarns, used 2/40 and 2/18 and so on to designate their yarn sizes.