It is clear from the prices paid at auction that, besides the origin of the wool and type of animal, the diameter of the fibre is the most important consideration for both suppliers and processors of wool. Its importance is largely due to its contribution to softness and to the fact that the finer the fabric is, the finer the yarn can be produced, which in turn generates luxurious comfort and pleasure for the wearer.
The fineness of a fibre is measured in micrometres (microns) with the symbol ‘μm’. (1 μm = one-millionth of a metre). Over the last ten years the average fibre diameter and the distribution of fibre diameter in the Australian clip has moved towards the finer quality, with 83% of the clip less than 24 μm, and 35% less than 20 μm. In Comparison: a human hair is about 100 μm.
Finer fibres tend to be more difficult and more costly to process and it is therefore important to know and understand the optimum way to process them mechanically. They bend more easily bur have less grip when it comes to spinning the yarn.
In the world of cloth the ‘quality’ is often referred to as Super or S100 up to S230. Does this mean finer is better? Not necessarily. As John Tellis of Germanicos Bespoke Tailors explains, “You can have a good 15-micron wool or a bad 15-micron wool. Fineness is just one quality component: length, strength, colour, and crimp are just as important, with the first two particularly so. Length is critical because the longer the fibre, the stronger the yarn that can be spun from it. Strength is also essential because the yarn must be twisted very tightly (hence the name high-twist fabric) to achieve a fine weave”.
The way in which the fabric is finished also plays an important role in the feel and look. There are Super 100’s wools that feel as sumptuous as Super 120’s or 140’s because of the finishing. But there is a mania among consumers and manufacturers for fineness and lightness. Which has revolutionised the making of a garment. The heaviest fabric used today is lighter than the lightest fabric used a decade ago. Ten years ago “13-micro wool” would have meant nothing. Fifteen years ago there was no production under 17 microns.