The direct systems are based on the weight or mass per unit length of yarn. Some typical direct systems are given below, together with their definitions. Please note that while the weight unit is gram, different lengths are used in the definitions.
Tex (g/1000m)
This is the mass in gram of one kilometre, or 1,000 metres, of the product. If one thousand meters of yarn weigh 20 grams or one hundred meters of the yarn weigh 2 grams, the yarn would be 20 tex. On the other hand, if 100 metres of yarn weigh 5 grams, then the count of the yarn will be 50 tex.
Dtex (g/10,000m)
This is called deci-tex. It is the mass in gram of ten kilometre, or 10,000 metres, of the product. It is a smaller unit than tex (1 tex = 10 dtex), and is usually used for fibres and filament yarns. A 167 dtex polyester filament would weigh 167 grams for every 10,000 meters of the filament.
Ktex (g/m)
This is called kilo-tex. It is the mass in gram of one metre of the product. It is a much larger unit than tex (1 ktex = 1,000 tex), and is usually used for heavy products such as slivers. If a sliver weighs 5 grams per metre, then the count of this sliver would be 5 ktex. The tex system (tex, ktex, dtex) is the preferred standard system. By definition, 1 ktex = 1,000 tex = 10,000 dtex
Denier (g/9,000m)
Denier is also used extensively in the industry, particularly for manufactured fibres and silk. It is the mass in gram of nine kilometres, or 9,000 metres, of the product.
By definition, 1 dtex = 0.9 denier If a 300 denier yarn is made up of 1.5 denier individual filaments, there will be a total number of 200 1.5 300 = filaments in the yarn
Indirect count system
Indirect count systems are not as straightforward as the direct ones. In the early history of yarn manufacture, different spinners, often geographically and culturally isolated from one another, devised their own ways of measuring yarn thickness. Consequently, there are numerous indirect count systems that have been, and continue to be, used in the industry. Some examples are given below, together with the mass and length conversions:
The metric count (Nm) is relatively straightforward. It is the length in metre of one gram of the product. For example, if one gram of yarn measures 40 metres, then the metric count of this yarn would be 40 Nm. Similarly, if one pound of cotton yarn measures 1,680 yards, or two hanks of 840 yards, the English cotton count of this yarn will be 2 Nec.
Please note that a hank of yarn is an unsupported coil consisting of wraps of yarn of a certain length. The conversions between different units will be discussed later. You may wonder how the strange length units such as 840 yard hank and 560 yard hank came about. The first mass-production spinner – the spinning-jenny was able to spin yarns simultaneously onto several bobbins and filled the bobbins up at the same time.
The bobbins were changed after 840 yards of cotton yarns were wound onto them. To estimate the thickness of the yarns, the spinner simply counted how many full bobbins were needed to balance a weight of one pound. For example, if 6 bobbins were needed to make up one pound, the yarn would be called a 6s yarn. Similarly a 20s worsted yarn means one pound of this yarn would fill up 20 bobbins, each with 560 yards of yarn wound on.
