antique carpets. Some fine carpets have silk warps dyed in different colours which create fringes in different colours known as "rainbow warps" in the rug trade. Mostly blue colours are used in the field, or a pale red. The predominant pattern used to be the Herati pattern, with a lozenge-shaped central medallion also filled with repeating Herati patterns on a different background colour. More realistic floral patterns are also seen, probably in rugs woven for export to Europe. Bijar carpets The town of Bijar lies around northeast of Sanadij. Together, these two towns and their surrounding areas have been major centers of rug production since the eighteenth century. Carpets woven in Bijar and the surrounding villages show more varied designs than Senneh rugs, which has led to the distinction between "city" and "village" Bijar rugs. Often referred to as "The Iron Rug of Persia", the Bijar rug is distinguished by its highly packed pile, which is produced by a special technique known as "wet weaving", with the help of a special tool. Warps, weft and pile are constantly kept wet during the weaving process. When the finished carpet is allowed to dry, the wool expands, and the fabric becomes more compact. The fabric is further compacted by vigorous hammering on nail-like metal devices which are inserted between the warps during the weaving. Alternate warps are moderately to deeply depressed. The fabric is further compacted by using wefts of different thickness. Usually one of three wefts is consideravly thicker than the others. The knots are symmetrical, at a density of 60 to over 200 per square inch (930–2100/ dm2), rarely even over 400 (6200/ dm2). The colours of Bijar rugs are exquisite, with light and dark blues, and saturated to light, pale madder red. The designs are traditionally Persian, with predominant Herati, but also Mina Khani, Harshang, and simple medallion forms. Frequently the design is more rectilinear, but Bijar rugs are more easily identified by their peculiar, stiff and heavy weaving than by any design. Bijar rugs cannot be folded without risking to damage the foundation. A specific feature is also the lack of outlining, particularly of the smaller patterns. Full-size "sampler" carpets showing only examples of field and border designs rather than a fully developed carpet design are called "vagireh" by rug traders, and are frequently seen in the Bijar area. New Bijar carpets are still exported from the area,