Generator

The same thread count, twice

Two cloths with identical thread counts and different yarn. The count is the same number in both; the fraction of the surface the threads actually occupy is not, and that fraction is what thread count is usually taken to mean.

5 essays call cover. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the weave its essay argues about.

Where it is called

Changing this generator changes every one of these figures.

$The same thread count, twice. Two cloths with identical thread counts and different yarn. The count is the same number in both; the fraction of the surface the threads actually occupy is not, and that fraction is what thread count is usually taken to mean.$ Setting and geometry

Thread count is not quality

It counts threads. It says nothing about how much of the cloth they cover, it can be inflated by counting plies, and it ranks fabrics in nearly the wrong order. The quantity it is mistaken for is cover factor, and that one is computable.

The same thread, on the loom and off it. One warp end in section over eight picks, drawn twice at the same scale. The thread is the same length in both panels; in the lower one more of that length is in the bends, so the cloth it spans is shorter. Nothing has been lost — the length has moved into the crimp. The thread's thickness and the height of its bends are drawn larger than scale so the interlacing is legible; the two panels' spacings are not.

After the loom

The cloth gains weight by losing size

Mass per unit area is the number a fabric is bought by, and it rises by eleven per cent when a cloth relaxes — with nothing added, nothing removed and no thread changed. The quantity is a ratio, and finishing moves its denominator.

$Where the twenty-eight comes from. The setting a cotton cover factor of 28 prescribes, and the setting at which the threads would cover the surface geometrically, against yarn count. They are one curve: the trade's scale is Peirce's diameter with the units taken out. Below them is the sett at which each weave actually jams, which is a fixed fraction of it.$ Setting and geometry

Where the cover factor comes from

A cotton cover factor is threads per inch over the root of the count, and the scale says twenty-eight means a covered surface. The twenty-eight is not a convention: it is the reciprocal of Peirce's yarn diameter, and the trade's practical ceilings of fourteen and twenty-two fall straight out of it.

The same yarn, flattened. One yarn's cross-section at five degrees of flattening, all drawn at one scale and all of the same area. Nothing is added: the yarn is wider because it is thinner. The cover rises for that reason alone, which is why a calendered cloth is more opaque than the cloth that went into the machine.

After the loom

Calendering is the cloth arriving at the other model

This site has carried two thread sections side by side since its foundation — Peirce's circle and Kemp's racetrack — and has been careful to say which produced any number. They are not two opinions about one yarn. They are one yarn on either side of a finishing machine.

The interchange budget against cover, at three yarn counts. The extension a plain cloth can reach with no thread stretching, plotted against its warp cover factor, for 10, 20, 40 tex yarn. The three curves coincide, because every length in Peirce's geometry is a multiple of the yarn diameter and a spacing measured in diameters is a cover factor — so the count divides out exactly and the maximum is at 0.407782 for all of them, at a budget of 7.2857%. That the curve has a maximum at all is the finding: crimp is what a cloth spends, so more of it should be better, and past this cover the weft has nowhere to put what the warp gives up. What the plot cannot show is the balance, which moves the height of the maximum a long way and its position hardly at all.

What cloth is

The most a cloth can give back

The extension a cloth can find without stretching a thread comes from crimp, so setting a cloth closer ought to give it more. It does, up to a point, and then takes it away again — and the point is a cover factor of 0.4078 at a budget of 7.2857 per cent, identical to six figures for every yarn count from five tex to a hundred.

The whole library · All essays