Cotton is classified, not only according to length and strength of fiber, but also according to the condition of the cotton on a basis called "middling". Middling cotton is creamy white, with no evidence of dirt or gin-cuts (fibers matted and cut) and with only a few pieces of leaf and immature seeds. Middling-fair, the best, has a perfect, lustrous, silky, clean fiber, whereas good-ordinary contains leaf particles, sticks, hulls, dirt, sand, gin-cuts, and spots. To indicate the degree of whiteness of the cotton, six distinct color groups are used: extra-white, white, spotted, tinged, yellow stained, and gray. Although the grades given above are significant to the manufacturer, a difference of 1/8 of an inch in the length of fibers is generally much more important than the difference between one grade and the next. Untreated cotton has no pronounced luster.
The diameter of the cotton fiber ranges from .0005 to .009 of an inch. Egyptian fibers have the smallest diameters and so can be spun into the finest yarns. A single cotton fiber will sustain a dead weight of from 2 to 8 grams. Such a fiber is not very strong, but the finished cotton cloth can be made very strong if tightly twisted.
Monday, November 09, 2009
It is harvest-time for Egyptian cotton, which is considered the finest in the world. Here is a bit of information on how the quality of cotton is assessed: