Have you ever wondered how knot counts of a rug are determined or if the knot count correlates with the price of a rug?
At our show gallery in Corona Del Mar, CA, we have noticed that many customers use the knot count of a rug to determine if one rug is superior to another. Although the KPSI or knots per square inch is a good indicator of how labor intensive the rug was to create, just counting the knots alone isn’t a good indicator of the quality of the Oriental Rug. Each country has a traditional knot count specific to that area. A medium knot count rug of 200 kpsi could be a very high quality example of weaving from a particular nomadic tribe.
How To Determine Knot Count
Knots per square inch or KPSI is calculated by counting the knots on the back of a rug across a vertical and horizontal inch and multiplying the two numbers. A vertical count of 14 and a horizontal count of 14 would give you a 196 KPSI. This seems rather straight forward, but different regions tend to use slightly different measurements in calculating knot count.
Oriental rugs from India measure knot count with two numbers such as “5/40” or “13/65.” The first number is called the bis and the second number is referred to as the bhutan. The bis is calculated by counting the number of knots in a 9/10th of a inch across a horizontal plane. The bhutan is calculated by counting the knots vertically in 4 ½ inches. To translate an Indian rug knot count into KPSI you multiple the two numbers, bis and bhutan, and then divide them by 4.05.
Persian rug knot counts are calculated differently dependent on what region weaved the rug:
- Tabriz rugs are calculated by using the rug’s Raj. The Raj is measured by counting the number of knots across 2 3/4inchs of rug. A standard quality Tabriz rug is 35 Raj or 162 KPSI.
- Nain Rugs use the term LAA. LAA is the number of yarn threads in an individual fringe at the end of a rug. The lower the LAA, the higher quality the rug is. The finest Nain rugs have a 4 LAA.
- Isfahan rugs have different colored threads between fringes and the rug’s pile called kheft. Kheft is measured across one meter and the number of different threads is an indication of quality.
Chinese rugs are measured using line counts. You calculate the line count by counting the number of knots measured in a linear foot of a rug. In most Chinese rugs, the vertical count is the same as the horizontal count.
Knots Are Not Everything
When deciding on your next area rug, learn where the rug was created. It will give you a better understanding of what the knot numbers mean and whether the knot count is indicative of quality from that certain region. But most importantly, knowing what region the rug came from you’ll better appreciate the little nuances that represent the weaving traditions of the region. The color, pattern, and complexity or simplicity is what’s used in deciphering the quality of the rug.
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