Knot density

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Back side of a Qom rug with very high knot density Knoopdichtheid ghom.jpg
Back side of a Qom rug with very high knot density
Noeud turc.jpg
Ghiordes knot
Noeud senneh.jpg
Senneh knot
The yellow yarn is the pile and the horizontal and vertical yarns are the warp and the woof

Knot density is a traditional measure for quality of handmade or knotted pile carpets. It refers to the number of knots, or knot count, per unit of surface area - typically either per square inch (kpsi) or per square centimeter (kpsc), but also per decimeter or meter (kpsd or kpsm). Number of knots per unit area is directly proportional to the quality of carpet. [1] [2] [3] [4] Density may vary from 25 to over 1000 kpsi, or 4 to over 155 kpsc, where ≤80 kpsi is poor quality, 120 to 330 kpsi medium to good, and ≥330 kpsi is very good quality. [2] The inverse, knot ratio, is also used to compare characteristics. [5] [6] Knot density = warp×weft while knot ratio = warp/weft. For comparison: 100,000/square meter = 1,000/square decimeter = 65/square inch = 179/gereh.

In business, engineering, and manufacturing, quality has a pragmatic interpretation as the non-inferiority or superiority of something; it's also defined as being suitable for its intended purpose while satisfying customer expectations. Quality is a perceptual, conditional, and somewhat subjective attribute and may be understood differently by different people. Consumers may focus on the specification quality of a product/service, or how it compares to competitors in the marketplace. Producers might measure the conformance quality, or degree to which the product/service was produced correctly. Support personnel may measure quality in the degree that a product is reliable, maintainable, or sustainable.

Knotted-pile carpet hand weaving technique in which supplementary weft yarns are wrapped around warp ends and cut to produce tufts or pile

A knotted-pile carpet is a carpet containing raised surfaces, or piles, from the cut off ends of knots woven between the warp and woof. The Ghiordes/Turkish knot and the Senneh/Persian knot, typical of Turkish carpets and Persian carpets, are the two primary knots. A flat or tapestry woven carpet, without pile, is a kilim. A pile carpet is influenced by width and number of warp and weft, pile height, knots used, and knot density.

Carpet Textile floor covering

A carpet is a textile floor covering typically consisting of an upper layer of pile attached to a backing. The pile was traditionally made from wool, but, since the 20th century, synthetic fibers such as polypropylene, nylon or polyester are often used, as these fibers are less expensive than wool. The pile usually consists of twisted tufts which are typically heat-treated to maintain their structure. The term "carpet" is often used interchangeably with the term "rug", although the term "carpet" can be applied to a floor covering that covers an entire house, whereas a "rug" is generally no bigger than a single room, and traditionally does not even span from one wall to another, and is typically not even attached as part of the floor.

For two carpets of the same age, origin, condition and design, the one with the higher number of knots will be the more valuable. Knot density is normally measured in knots per square inch (KPSI) which is simply the number of vertical knots across one inch of carpet multiplied by the number of horizontal knots in the same area. Average knot density varies between region and design. A rug could have a knot density half that of another yet still be more valuable, KPSI is only one measurement of quality and value in Persian carpets. [7]

A square inch is a unit of area, equal to the area of a square with sides of one inch. The following symbols are used to denote square inches:

Persian carpet type of handmade carpet

A Persian carpet or Persian rug, also known as Iranian carpet, is a heavy textile made for a wide variety of utilitarian and symbolic purposes and produced in Iran, for home use, local sale, and export. Carpet weaving is an essential part of Persian culture and Iranian art. Within the group of Oriental rugs produced by the countries of the so-called "rug belt", the Persian carpet stands out by the variety and elaborateness of its manifold designs.

Knot density is related to and affects or affected by the thickness of the length of the pile and the width of the warp and woof, [8] and also the designs and motifs used and their characteristics and appearance. [8] "In rugs with a high knot density, curvilinear, elaborate motifs are possible. In those with a low knot density (as well as kilims), simpler, rectilinear, motifs tend to prevail." [3] "A carpet design with a high knot density is better adapted to intricate and curvilinear designs, which of necessity must have a shorter pile length to avoid looking blurry. A carpet with a lesser knot density is better adapted to bold, geometric designs and can utilize a long pile for softer, more reflective surface that appeals to the sense of touch." [9]

Pile (textile) upright loops, tufts, or strands of yarn extending from the ground of a fabric

Pile is the raised surface or nap of a fabric, consisting of upright loops or strands of yarn. Examples of pile textiles are carpets, corduroy, velvet, plush, and Turkish towels. The word is derived from Latin pilus for "hair"

Hand-tying of knots is a very labour-intensive task. An average weaver can tie almost 10,000 knots per day. More difficult patterns with an above-average knot density can only be woven by a skillful weaver, thus increasing the production costs even more. An average weaver may tie 360 knots per hour (1/10 seconds), while 1200 knots approaches the maximum a skilful weaver can tie per hour. [2]

Weaving technology for the production of textiles

Weaving is a method of textile production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. Other methods are knitting, crocheting, felting, and braiding or plaiting. The longitudinal threads are called the warp and the lateral threads are the weft or filling. The method in which these threads are inter-woven affects the characteristics of the cloth. Cloth is usually woven on a loom, a device that holds the warp threads in place while filling threads are woven through them. A fabric band which meets this definition of cloth can also be made using other methods, including tablet weaving, back strap loom, or other techniques without looms.

In the late fifteenth century a "carpet design revolution" occurred, made possible by finer yarns, and before this time it is rare to find carpets with ≥120 kpsi but by the next century carpets with three to four times that density were fairly common. [9] For example, the Pazyryk carpet (ca. 400 BCE) is around 234 kpsi and the Ardabil Carpets (ca. 1550 CE) are 300–350 kpsi. A fragment of a silk Mughal carpet in the Metropolitan Museum of Art has a knot density of 2,516 kpsi and a silk Hereke prayer rug (ca. 1970 CE) contains 4,360 symmetric kpsi. [5] However, the rug with the highest knot density is a silk Hereke masterpiece by the Özipeks workshops, having an incredible density of approximately 10,000 kpsi, with a production time of about 15 years. (FN5a -

Ardabil Carpet

The Ardabil Carpets are a pair of famous Persian carpets in the collections of the Victoria and Albert Museum in London and the Los Angeles County Museum of Art. They are examples of Ardabil rugs.

Metropolitan Museum of Art Art museum in New York City, New York

The Metropolitan Museum of Art of New York City, colloquially "the Met", is the largest art museum in the United States. With 6,953,927 visitors to its three locations in 2018, it was the third most visited art museum in the world. Its permanent collection contains over two million works, divided among seventeen curatorial departments. The main building, on the eastern edge of Central Park along Museum Mile in Manhattan's Upper East Side is by area one of the world's largest art galleries. A much smaller second location, The Cloisters at Fort Tryon Park in Upper Manhattan, contains an extensive collection of art, architecture, and artifacts from Medieval Europe. On March 18, 2016, the museum opened the Met Breuer museum at Madison Avenue on the Upper East Side; it extends the museum's modern and contemporary art program.

Hereke is a town in Kocaeli province, Turkey, located to the north of the Gulf of İzmit, near Istanbul. It is famous for Hereke carpets. It was bound to Gebze district until transferring to Körfez in 1987 and had municipality status until 2009. It consists of 17 Ağustos, Agah Ateş, Cumhuriyet, Hacı Akif, Kışladüzü, Şirinyalı and Yukarı Hereke mahalles. It can be reached by minibus, public bus, Adapazarı Express train, ship and sea bus.

In Persian, reg (raj, rag, Persian: "row, course") refers to the knots per gereh (Persian: "knot"), which refers to a unit of approximately 2.75 inches. [5] Dihari is a unit of 6,000 knots used to measure production in India. [5]

See also

Related Research Articles


A kilim is a flat tapestry-woven carpet or rug traditionally produced in countries of the former Persian Empire, Iran, Azerbaijan and Turkic countries of Central Asia. Kilims can be purely decorative or can function as prayer rugs. Modern kilims are popular floor-coverings in Western households.


Paithani is a variety of sari, named after the Paithan town in Aurangabad Maharashtra state where they are woven by hand. Made from very fine silk, it is considered as one of the richest saris in India. It is one of the most famous saris in India.It is also considered the finest silk in India.

Oriental rug Type of textile

An oriental rug is a heavy textile made for a wide variety of utilitarian and symbolic purposes and produced in “Oriental countries” for home use, local sale, and export.

Pile weave woven fabric in which a pile is produced above the ground by the use of a separate pile warp or pile weft

Pile weave is a form of textile created by weaving.These fabrics are characterized by a pile, a looped or tufted surface that extends above the foundation or ground weave. The pile is formed by supplemental yarn running in the direction of the length of the fabric or the width of the fabric. Pile weaves include velvet and corduroy fabrics and machine-woven Berber carpets.

Anatolian rug

Anatolian rug is a term of convenience, commonly used today to denote rugs and carpets woven in Anatolia and its adjacent regions. Geographically, its area of production can be compared to the territories which were historically dominated by the Ottoman Empire. It denotes a knotted, pile-woven floor or wall covering which is produced for home use, local sale, and export. Together with the flat-woven kilim, Anatolian rugs represent an essential part of the regional culture, which is officially understood as the Culture of Turkey today, and derives from the ethnic, religious and cultural pluralism of one of the most ancient centres of human civilisation.

The manufacture of textiles is one of the oldest of human technologies. To make textiles, the first requirement is a source of fibre from which a yarn can be made, primarily by spinning. The yarn is processed by knitting or weaving, which turns yarn into cloth. The machine used for weaving is the loom. For decoration, the process of colouring yarn or the finished material is dyeing. For more information of the various steps, see textile manufacturing.

Units of textile measurement systems for measuring textiles

Textile fibers, threads, yarns and fabrics are measured in a multiplicity of units.

Hereke carpet

Hereke carpets used to be only produced in Hereke, a coastal town in Turkey, 60 km from Istanbul. The materials used are silk, a combination of wool and cotton and sometimes gold or silver threads.

Ardabil rug

Ardabil rugs originate from Ardabil located in the province of Ardabil Province in northwestern Iran, 639 kilometers from Tehran. Ardabil has a long and illustrious history of Persian carpet weaving.

Azerbaijani rug intangible cultural heritage

Azerbaijani rugs are a product of Azerbaijan, an ancient center of carpet weaving. The Azerbaijani rug is a traditional handmade textile of various sizes, with dense texture and a pile or pile-less surface, whose patterns are characteristic of Azerbaijan's many carpet-making regions. Traditionally, since ancient times the carpets were used in Azerbaijan to cover floors, decorate interior walls, sofas, chairs, beds and tables.

Kerman carpet

Kerman carpets are one of the traditional classifications of Persian carpets. Kerman is both a city and a province located in south central Iran, though the term sometimes describes a type which may have been made elsewhere. Kerman rugs are prized for a wide range of designs, a broad palette, use of natural dyes and fibers, great tensile strength and abrasion resistance, and expert color combinations. Typical manufacturing used an asymmetrical knot on cotton foundation, but rare examples include silk or part silk piles, or silk foundations with wool pile.

Azerbaijani carpet weaving

The Azerbaijani carpet is a traditional handmade textile of various sizes, with dense texture and a pile or pile-less surface, whose patterns are characteristic of Azerbaijan’s many carpet-making regions. Carpet making is a family tradition transferred orally and through practice.


Soumak is a tapestry technique of weaving strong and decorative textiles used as rugs and domestic bags. Baks used for bedding are known as Soumak Mafrash. Soumak is a type of flat weave, somewhat resembling but stronger and thicker than kilim, with a smooth front face and a ragged back, where kilim is smooth both sides. Soumak lacks the slits characteristic of kilim, as it is usually woven with supplementary weft threads as continuous supports.

Oriental Carpet Manufacturers

The Oriental Carpet Manufacturers (OCM) was a London-based company involved in the production of, and trade with, Oriental carpets. Established in 1907/8 in Istanbul, the company set up and controlled their own carpet manufactures in the central Anatolian region around the town of Konya, and from 1911 onwards, in the Hamadan Province in northwestern Iran. In 1968 it was sold, and merged with one of its former affiliates, the Eastern Kayyam Company. From 1924 until 1948, OCM was led by Arthur Cecil Edwards, who, after retiring, wrote a text book on Persian Carpets, which is still in print today.

Lazy line

A lazy line or section line is a technical feature of weaving which describes visible diagonal joins within a woven textile. It results from interlacing wefts joining adjacent warp sections woven at different times. Successive rows of turnarounds of discontinuous wefts create a diagonal line which, in pile rugs, is best seen from the back side, and from the front side only if the pile is heavily worn. A lazy line is created when the weaver does not finish a rug line by line from one side to the other, but sequentially finishes one area after the other.


  1. "Silk Rug Cleaning - Modern and Oriental Rug Cleaning", "The quality of an Oriental rug – and all silk rugs in general, is determined by a most important factor: the rug's knot density." Accessed: December 13, 2016.
  2. 1 2 3 Goswami, K.K.; ed. (2009). Advances in Carpet Manufacture, p.239. Woodhead Publishing in Textiles: Number 87 (The Textile Institute). ISBN   9781845695859. "Knot density is an indicator of quality; the greater the number of knots per square inch (kpsi), the better the quality of the carpet."
  3. 1 2 Cucker, Felipe (2013). Manifold Mirrors: The Crossing Paths of the Arts and Mathematics, p.89-90. Cambridge University. ISBN   9781107354494. "The knot density...not only provides a measure of the work required to produce a given rug but also sets limits to the possible designs."
  4. Daniel, Elton L. and ʻAlī Akbar Mahdī (2006). Culture and Customs of Iran, p.138. Greenwood. ISBN   9780313320538. "Another basic factor in determining the quality of a carpet is knot density...—more knots indicate finer work, better quality, and a higher price.
  5. 1 2 3 4 Stone, Peter F. (2014). Oriental Rugs: An Illustrated Lexicon of Motifs, Materials, and Origins , unpaginated. Tuttle. ISBN   9781462911844. Knot density: "In a knotted pile fabric, the knots per unit area. The product of the vertical or warp-wise knot count per linear unit measure multiplied by the horizontal or weft-wise knot count per linear unit measure." Knot ratio: "In a knotted pile carpet, the vertical or warp-wise knot count per linear unit measure divided by the horizontal or weft-wise knot count per linear unit measure."
  6. (1990). Textile Museum Journal , Volumes 27-37, p.68. "Knot density itself is less significant than the ratio of horizontal to vertical knot counts."
  7. Murphy, Brian (2006). The Root of Wild Madder: Chasing the History, Mystery, and Lore of the Persian Carpet, p.47. Simon and Schuster. ISBN   9780743264211. "Knot counts appear in almost every carpet book, catalogue, and auction guide. It's a convenient yardstick to compare the intricacy of the work...But it's a seriously flawed method to assess quality or beauty."
  8. 1 2 Tzareva, Elena (1984). Rugs & carpets from Central Asia: the Russian collections , p.12-3. Penguin. ISBN   9780140063691. "The greater the knot density, the thinner the weft and warp yarns and the more weakly are they twisted; the smaller the density, the coarser are the foundation yarns." "In small pieces where a high pile was not required, the knot density was often far greater. As less time was needed to weave smaller items, their makers demonstrated greater care, choosing a more complex design that necessitated a greater knot density."
  9. 1 2 Denny, Walter B. (2014). How to Read Islamic Carpets, p.43 & 61. Metropolitan Museum of Art. ISBN   9780300208092.