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What is kpsi?
KPSI (stands for Knots Per Square Inch) is measured on the reverse side of a hand knotted Oriental Rug. Individual Knots are counted 1" vertically, and 1" horizontally, then multiplied together to arrive at the Knots Per Square Inch. KPSI is one of many ways rug experts may evaluate oriental rugs. KPSI is also sometimes referred to as knot density and knot count, which is somewhat of a quick simplification of what can be a complex equation of understanding quality: That is to say, not all countries, regions and cities have the same standardized knot density measure of KPSI. Within the Oriental Rug Industry, knot count may be measured in many different ways. For more information, see below.
How Important is KPSI?
KPSI should be taken with a grain of salt when considering the overall scope, valuation and investment potential of any given Oriental Rug. Knot count can vary greatly in Oriental rugs depending on region in which they were created, vintage of the piece, and sometimes even the construction of such a rug.
How do I count KPSI?
KPSI is measured on the reverse side of the carpet, 1" vertical, and 1" horizontal. After counting both rise and run, multiple the two together and you will have the KPSI for any given rug! For more information and pictures of, take a look at how to calculate Knot Count.
Is Knot Count as easy as it sounds?
To the untrained eye, knot count can be very tricky. One common mistake is to count a double ply yarn as two separate knots. This can easily throw off final KPSI by a significant amount. For example, a carpet with a knot count (when properly counted) may measure 10 knots horizontal, 10 knots vertical (100 KPSI), a miscounted KPSI incorporating double yarn ply may lead one to believe a perceived knot count of 10 knots horizontal, and 20 knots vertical. This misinterpretation can DOUBLE the knot count!
There are many other mistakes even some less reputable sellers may make when advertising their Oriental Rug's knot count. Some of these misrepresentations may be a simple mistake due to lack of understanding different types of knots, loom orientation (offset), and yarn ply as previously mentioned. All these factors can mislead the average buyer to perceive higher knot count than is actually employed in any given weaving. Take a look on another post on types of knots used in the weaving of Oriental Rugs.
What to Consider:
One of the most important things to bear in mind is just because
two different rugs have been woven in the same city or region, does
not necessarily mean the two rugs are of equal KPSI or knot count. There are different types of ways to evaluate knot density depending on
country and region of weavings. For example, Oriental Rugs woven in
tabriz, Iran implement a quality system known as the raj (believed by many to have originated by the length of one rolled cigarette), which can be
translated to KPSI, however is not their proper measurement system. Same is true for rugs from China, which are actually measured in Line, which also may be translated into KPSI. Take a look at this knot count chart to understand loose translations of different Knot density measures used around the globe!
What is a good KPSI?
There is no one way to evaluate what is a good knot count for all Oriental Rugs. To give an example of the knot count predicament is to understand how greatly these qualities vary depending on the type of rug. A
loose example of this would be comparing knot count of Nain Oriental
Rugs vs. Peshawar rugs. A peshawar carpet containing 250 KPSI would be
a very unique and unusually high knot count for this genre of rug.
However, an Oriental Rug from nain with 250 KPSI would be on the very
low end of the production scale. Relatively speaking, knot for knot
comparing the two, there is no dollar amount an individual can place on
any single knot woven, and simply put, there is no one "ideal" knot count to use as a guideline when researching the purchase or acquisition of your new Oriental Rug(s)!
What are some of the KPSI ranges?
Oriental Rugs can have knot counts that vary from as little as 15, to as many as 2500+. While a KPSI of 800 is very unusual, there are some extremely fine examples which are woven as high as, and even above 2500 KPSI! Take a look at this small prayer rug woven in India with a KPSI of over 1400, and another fine example from Turkey known as a Kum Kapi measuring in close to 1300 KPSI.