All handmade rugs are made on a loom, which supports the foundation of the rug into which the pile is knotted. Two types of looms are in use in the Orient: the horizontal or flat loom and the vertical or upright loom.
The warp forms the base, or “foundation,” upon which the rug is knotted. It consists of a series of parallel vertical threads (the warp threads) stretched taut around the two beams of the loom. The number of warp threads strung on the loom determines the fineness of the weave.
The weft shots, shoots or shotz pass horizontally in and out of the warp threads. In the piled part of a rug, the wefts provide support of the knots. After completing a row of knots, the weaver passes one or more weft shots in and out of the warp threads then beats the fabric down by hand using a heavy metal comb.
Generally speaking, with regard to the whole weight of the carpet, nearly 16-20% is the warp, another 10-18% is the weft, and the balance, 50-70%, represents the pile.
The Raw Materials
Needless to say, sheep wool is one of the basic elements in the carpet industry; it is usually used to weave the pile of a carpet. Many years ago, some of the Hamedan and Baluch rugs were woven with camel wool.
Iranian sheep have thick wool, and more than 60-70% of the wool is the heterotypical variety. Due to this fact, it is a very suitable material for carpets, as the warp is thick, coarse and strong. The quality of wool obtained from sheep raised in mild and mountainous areas is much better than that from sheep that are pastured in humid and low-lying grazing land. Moreover, the quality of wool sheared from sheep in the spring is always better than that sheared in the autumn.
Sheep wool contains many external substances and these should be carefully separated before spinning. These substances include fat, sweat and urine. The dried wool also contains potassium and sodium salts, water, and ointments applied to the body of the animal to heal its wounds. To remove these substances, it is necessary to completely wash the wool. Then the water is thoroughly wrung out and the wool is spread on a clean area to dry. This operation can be carried out manually or at wool-washing factories that are equipped with mechanical apparatus. After the drying process, the spun and skinned wool is dyed in the preferred colors at special dyeing factories. The spinning can be accomplished either by hand or by machinery. In the latter case, the large quantity of wool is uniformly spun and twisted. Hand-spun wool is mostly used in the villages and in the quarters of tribal carpet weavers.
This term refers to the soft wool that grows close to the skin of sheep, goats and camels. A comb is used to extract this fine wool, which clings to the teeth of the comb. It is one of the principal elements from which fine and fairly expensive rugs are made.
Cotton fiber has an important role in the carpet weaving industry, and it has seen increased use for weaving the warp and weft of the carpet, as moths are not attracted to cotton. If the warp and weft of carpets are made of cotton, the moths only damage the pile without causing any holes, and it is much easier to create a new layer of pile on the lattice of the warp and weft that has been left intact. Cotton fiber is not good for making the pile of a rug; instead, due to its strength and inflexibility, it is suitable only for making the warp and weft.
Produced by the larva of a species of moth commonly called the silkworm, silk has been successfully cultivated in Iran for centuries. The finest silk for rug making traditionally comes from an area around the Caspian Sea. This region produces a type referred to as Rasht Silk, which is regarded as the best in the world. Because of the high price of the raw material, the production of silk rugs has sharply decreased. Silk fibers can also be used to make the warp, weft and pile of a carpet. When compared with wool fibers of equal diameter, they are much stronger.