Isfahan rug is one of the fine woven carpets, that number of its  wale is above 40 (Isfahan rugs have 800 knots per square inch). Knots are Persian (asymmetric) and usually with double weft, so rugs have been woven finely.
In Isfahan, like other Persian weaving parts, such as Kashan, Qom, Kerman, Yazd, … knitting is done by hand, without using hook. Isfahan weavers, doing wefts by a wooden tool called "Koji", but they hit knots on the warp by heavy combs. Usually Isfahan rug is woven in small and middle sizes and hardly in big sizes. They are mostly in 1.1/2 zar, two zar, curtain size, …(zar =104 cm). It is hardly seen that runners have been woven in Isfahan.
Fine woven rugs and silk motifs of Isfahan are very famous and outstanding. Usually these rugs are woven on silk warp. Fringes of these rugs sometimes reach to 15 centimeters. Round shaped rugs are also woven here.Shawl (a kind of kilim weaving) in final part of rugs (3-5 wale) is another customs of carpet weaving in Isfahan.Vertical looms are used in weaving of Isfahan carpets. In Isfahan looms a piece of wood called "Pelepich" is used, that passes through strings of lower warp and connected by metal wires to beneath of loom. This wooden piece helps in final part of weaving, when lowering down the rug and also short warp knotting occurs, when knotting upper warps on the top of loom is not possible, weaving will be continued by transferring "Pelepich" to upper level and passing upper warps through and connecting it to the top of loom by metal wires.Turkish knots are also used in Isfahan weaving. These knots are used only in rugs named "Armenian Weaving", which are woven in other cities of this province, such as in Isfahan weaving, plain parts are usually woven by double knots and fine parts (fine motifs) by single knots. Some of weavers use more delicate piles in some parts of fine motives. This difference in delicateness of piles makes lower piles of fine motives, which is called "Low Weaving Carpet".As far as we know , before Safavi's period , first carpets were almost made from camel's , Goat's and cow's wool in the form of felts. These felts were being produced in their primary shapes and designs by rolling and pressing the wool and by doing different activities on them such as various methods of washing . After Safavi's period , when architecture was on the top , new building were built with the old styles , and considerable changes were made to these buildings , specially to the royal structures , mosques and  religious theaters.Then this buildings and structures were decorated by tilery designs such as Gol-Barg and band-Eslim and Hand-woven fine carpets . this kinds of carpets were particulary innovated in Iran , specially in the capital city Isfahan and this carpet innovation, little , was transferred to the other major cities such as azarbaijan , kerman, shiraz, etc. due to the beauty and smart of this kind of hand-woven fine carpets, they were gradually exported to other countries as per the period situations . from this time on wards, more quantity and variety of product were taken into manufacturers consideration per year, and therefore, the product became one of the most important Iranian goods to export, and designers, dyers, weavers and manufacturers increased quality , quantity, finess and beauty so that this valuable art is one of the best Iranian hand-industry.A brief explanation on hand-woven carpet production process from the beginning to the end :The necessary raw materials are : sheep's wool , silk-worm cocoon and cotton thread. the silk worms spin the silk and cottons and changes them threads separately. Each silk -worm cocoon is made of maximum 18 very fine strings. Then this wools ,silk and cottons are dyed in dying workshop in different colors. Between 15 to 40 colors are included in different carpets. These colors are divided into two groups : natural or herbaceous colors and chemical colors. If they are used properly , they will be stabilized on the carpets . the natural or herbaceous colors are mainly extracted out of plants such as madder , alizarin , walnut shelf , pomegranate shelf , indigos, vitriol. After dying and weaving ,to match the carpet colors with the end user satisfaction ,they wash the carpets with different methods of washing such as rinsing and ,soap rubbing and rag washing .during washing the carpets lose their colors between 10 to 30% which causes the carpets find more soothing colors . now the carpet colors are ready and it is carpet selvage is subsequently connected to the weaving seat that is a wooden or metal frame. The carpet hand-weaving begins now .you can see a sample of a semi-woven carpet in the picture . There are two different weaving : one is named complete or twisted noose neither detaches from the carpet unless the carpet itself is worn-out after a long time. Another one is named crochet noose. In the recent type of noose they connect the wool to the selvage with a hook. It does n' t have durability and can be taken out of the carpet just with fingers. the advantage of Isfahan made carpets is that , due to their long history , they are woven with the first type of noose , namely complete or twisted noose.

 All about Persian Carpet

Carpet designs
The carpets designs are usually acquired from the old tiler designs and are sketched on the papers by drughtsmen . then the sketched design on the paper must be colored. At this step the painter decides on the proper colors for the ground and the margin of the carpet, and the based on his selection , he paints different components of the carpet design such as flowers, leave, trees frame, triangular , central flower, etc. then they stick the design papers on small boards and cover the boards with varnish to avoid colors from erasure and give the design boards to the carpet weavers and they begin to weave the carpet from their first streak.

Carpet weaving
Now the weaver catches each two threads of the selvage with his finger, and using the finger of the other hand, Throws the wool to one layer of the selvage and with the wool head gives one twist to the other of the selvage and pulls down both heads of the wools at first and , in the same case he changes the threads to nooses. After one streak is finished, he puts every other threads on the top of the selvage and pounds over them by a device named Daftin (comb) to make the nooses firm and tidy. Then he cuts the extra wools by a scissors and this procedure is repeated till the end of the carpet . The end-time of this repetition depends on the size of the carpet and will last from 6 months up to 6 years. After weaving is finished, the carpets are taken to the special workshop and some operations such as thinning the carpet, face-washing, soap-washing, bright-washing, rag-washing, thread-head deletion and leather-sewing are done on them. At this step the carpets and rugs are ready to be exported all over the worlds.