Counting Knots in Oriental Rugs
Rug Measurements Guide: Understanding KPSI and Other Metrics
When assessing the fineness of a rug's weave, various measurements are used depending on the region it comes from. The primary measurement is KPSI (knots per square inch), which affects the clarity and sharpness of the rug's design, similar to pixels on a screen. This article will help you understand different rug measurements and how they translate into KPSI.
KPSI: The Core Measurement
KPSI is typically determined by counting the knots on the back of a rug across a vertical and horizontal inch and multiplying the two numbers. For example, a 12x12 rug would have 144 KPSI. A fine rug may have a square inch measurement of around 20/20 or 20/21 (~ 400 KPSI). However, the knotting in some rugs may make them appear to have more knots than they actually do.
Indian Rug Measurements: Bis and Bhutan
In regions like Bhadohi, India, Oriental rugs are measured using two numbers, such as "5/40", "9/60", or "13/65". These numbers are called the Bis and Bhutan. The bis is the number of knots in 9/10ths of an inch horizontally, while the Bhutan represents the number of knots vertically in 4 1/2 inches. To calculate the KPSI of an Indian rug, multiply the two numbers and divide by 4.05.
Chinese Rug Measurements: Line Counts
Chinese rugs use line counts, typically described as "90 line" or "120 line", which refer to the number of knots (pairs of warps) measured in a linear foot. In Chinese rugs, the number of knots is usually the same vertically and horizontally. For example, a 120 line carpet has 100 KPSI.
Pakistani Rug Measurements: Double and Single Knot
Pakistani rugs are often described by the actual number of knots vertically and horizontally, such as "16/16" or "16/18", which would equal 288 KPSI. These are called "double knot" rugs. "Single knot" rugs may appear to have more knots than they do due to the shape of the knots. These rugs are measured similarly, for example, 9/16 translates to 144 KPSI.
Persian Rug Measurements: Raj, LAA, and Kheft
Persian rugs from Tabriz use the term Raj, representing the number of knots across 2 3/4 inches of a rug. In Nain rugs, LAA is used, which is the number of yarn threads in an individual fringe at the end of a rug. The lower the LAA, the higher the rug's quality. Isfahan rugs may have different coloured threads, called Kheft, between the fringe and the rug's pile, which is measured across one meter to indicate quality.
Contact Us for KPSI Information
If you're interested in knowing the KPSI of any of our rugs, feel free to contact us by phone at (0141 420 6989) or email. We'll be more than happy to provide you with the KPSI information you need as soon as possible.