Yarn count, simply said, is a measure of the fineness of a yarn. Thus it gives an estimation of how thick or thin a yarn is. We can also measure the diameter of the yarn and express it in inches etc. However, the yarn is not exactly circular in cross section. Also most yarn are soft and compressible and hence the moment we apply some scale etc, it gets deflated.
A method, which is popular in cotton yarns, is to measure the length of a particular weight of yarn. Thus the yarn which has more length will be finer than the other yarn which has less length of the same weight. For cotton yarn this particular weight is one pound, and the length is measured in 840 yards. Thus a cotton yarn has one count, if we measure the length of one pound of this yarn, and it comes out to be 840 yards. If it comes out to be 1680 or 2 x 840 yards for one pound of weight, we call it as a yarn with 2s count and so on. Generally thick shirtings are in the range of 30s count, medium weights are in 60s count and finer weights in 80s count.
For cotton the length is taken as 840 yards and weight as one pound. For Linen, the length is 560 yards. Thus the yarn of a linen is of count 20 if in one pound there is 20 x 560 yards of length.
Now, in real world, we come across with two yarns twisted together. If we twist two yarns of 40s count, we call the yarn as that of 2/40s count. If we twist 3 yarns of 60s count, we call it as a yarn of 3/60s count.
A method which is also popular in silk is to weigh a particular length of the yarn. In this system, the yarn which has less weight of the same length than some other yarn will be finer than the other yarn. Commonly this is called denier. In denier system, the unit of weight is grams and that of length is 9 km. Thus if a silk yarn weighs 24 grams of 9km of length this is said to be of 24 denier.
The General Relation ship between count and denier is given by the fact that no of deniers is equal to 5315 divided by no of counts thus if cotton is of 30s count then it will be of 5315/30 or 177.66 deniers.
Simply speaking, more the count, finer is the yarn. More the denier, coarser is the yarn.
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