Materials
Materials used in carpet-making determine what sort of motifs can be designed. For example, a fine pile weave allows for curvilinear designs while a slit-tapestry technique is ideal for geometric patterns. Yarn used for carpets is predominantly spun wool (usually sheep, but can be goat or camel), silk, cotton, hemp, linen, and jute. The versatility, strength, and heat retention of wool make it popular, besides the fact that it is cheap and readily available for nomadic tribes.
The yarn
Wool is often times the only material used to make a carpet, and sometimes it is only used for the pile. It is combed to end up with fibers that are parallel to each other, then spun to make for a yarn that is hard, lustrous, smooth, and strong. Fiber and motion are set in rhythm to create a smooth thread, a feat which women in carpet-making regions master enough to engage in other activities while spooling the thread.
Silk yarn comes second in importance in carpet-making. A continuous filament is secreted by the Bombyx mori caterpillar, also known as the silk worm, which is then spun. Silk reflects light thanks to its uninterrupted surface, unlike wool. Its strength in relation to its thickness makes it ideal for very detailed designs such as the Hereke carpets of Turkey.
Cotton is the other yarn used for carpets. It is most often used on the warp and weft but its brilliant white comes in handy to contrast with the other colors on a motif. Some Indian carpets use an all-cotton pile.
The Loom
The loom is what holds warp threads under tension to enable the fabric of the carpet to be woven. Basically, it is made up of two horizontal bars that stretch out columns of thread – which can be either wool, silk, or cotton, as described above. The width and straightness of the loom will have an impact on the final product as it may be limiting in size and a crooked loom will make a crooked design, which may also add to its charm. Since the warp is wrapped around the top part of the loom, it can be continuously unwrapped to make very long carpets. A third bar separates the alternate warps facilitating the insertion of the rows of weft. Weavers use a heavy metal comb to beat down the layers of weft and a sharp curved knife or scissors if they are dealing with pile carpets.