Knotted Rugs and Carpets

Knotted pile carpets, combining beauty, durability, and possibilities for unlimited variety, have found the greatest favor as floor coverings. Long ago, weavers first began to produce pile fabrics or fabrics with a surface made up of loops of yarn, attempting to combine the advantages of a woven textile with those of animal fleece.

Knotted pile is constructed on the loom on a foundation of woven yarns, of which the horizontal yarns are called weft yarns and the vertical are called warp yarns. Colored pile yarns, from which the pattern is created, are firmly knotted around two warp yarns in such a way that their free ends rise above the woven foundation to form a tufted pile or thick cushion of yarn ends covering one side of the foundation weave.

The knots are worked in rows between interlocking, tautly drawn weft yarns that keep every row of knotted tufts securely in place in the foundation. When a row of knots is tied, it is beaten down against the preceding rows with a heavy malletlike comb so that on the front the pile completely conceals both warp and weft. When an area has been woven, the pile ends are sheared to an even height: short on the more aristocratic type and as much as an inch on some shaggy nomadic rugs.

There are various ways of knotting the pile yarn around the warp yarn. The Turkish, or symmetrical, knot is used mainly in Asia Minor, the Caucasus, Iran (Persia), and Europe. This knot was also formerly known as the Ghiordes knot. The Persian, or asymmetrical, knot is used principally in Iran, India, China, and Egypt. This knot was formerly known as the Senneh (Sehna) knot.

The Spanish knot, used mainly in Spain, differs from the other two types in looping around only one warp yarn. After the 18th century it became extremely rare. The kind of knot used affects the delicacy and tightness of the pile. Knotting each pile yarn by hand is comparable to setting small pebbles in a mosaic, and expert execution is vital in achieving a beautiful finished product. Angular-patterned carpets requiring only a coarsely knotted pile are easier to produce than curvilinear and finely patterned ones, which require finer material and a much more densely knotted pile for clear reproduction of their intricate designs.

Some Chinese carpets have fewer than 20 knots per square inch (3 per square centimetre); certain Indian ones, more than 2,400. The highest density can be achieved with the Persian knot.

Metal-covered thread can be added to the pile, heightening its colourfulness. The gold and silver thread used in this procedure lies flat against the woven foundation, giving the appearance of low relief. Metal-covered thread wears quickly and loses its lustre, however, making it less suitable for floor coverings than for hangings.

Many carpets do not have knotted pile. Called kilims, they are woven similarly to tapestries. The weft yarns of a given colour area never cross into another area, and if the weft yarns of different colour areas are hooked around adjacent warps rather than around one another or around warp yarn, small slits are created where different colours meet. In soumak carpets, one or two rows of coloured pattern weft alternate with an invisible functional weft. Weft wrapping with passes of alternate rows given a differing direction, or slant, produces a herringbone effect.

Embroidery has rarely been used on floor coverings. Embroidered rugs are almost exclusively European and American, except for certain Turkmen kilims and Turkish cicims (ruglike spreads or hangings) and some felted or jute-backed Indian and Kashmiri rugs decorated with chain stitching. Only relatively strong backings can be used. European embroidered rugs feature designs of counted stitching (the cross-stitch—of the Arraiolos rug, for example—and the gros point and petit point of needlepoint) that cover the entire surface.