The Nain workshop founded by Fatollah Habibian, who is said to have begun weaving in 1903 under his father and, after the family's older styles lost their market and its stock was sold off, started his own workshop with his brother. He is regarded as the creator of the modern Nain rug, and the name has become synonymous with Nain rugs: Persian-knotted, densely woven, intricately designed, with silk highlights and a modern look. Habibian is one of the few well-known signatures found on Nain rugs, most of which are unsigned, and the founder's grandsons carry the workshop on.
A Persian grading scale specific to Nain rugs, in which a number such as 4, 6 or 9 counts the layers (la, "layers") of thread at each warp position. The scale runs backward: the lower the number, the denser the knotting, typically about 650 KPSI for 4 la, 400 to 500 for 6 la and 200 to 300 for 9 la (roughly 10,100, 6,200 to 7,750 and 3,100 to 4,650 knots per 10 by 10 cm).
Fine Persian rugs from the city of Nain, near Isfahan in central Iran, where rug weaving began only in the 20th century on Isfahan's model and the Habibian workshop made the name known worldwide. The wool pile, often with silk highlights, is knotted on a cotton foundation at roughly 200 to 700 knots per square inch or more (about 31 to 108 per cm²). Density is graded by la (“layer”): the lower the number, the finer the rug, from about 650 KPSI at 4 la to 400-500 at 6 la and 200-300 at 9 la. Designs are curvilinear florals in medallion, allover or Shah Abbasi layouts, mostly on a cream or ivory ground with blue, beige and gray. Most Nain rugs are unsigned, though the Habibian signature is a well-known exception, and large sizes are scarce and costly.
The name of a weaver or workshop woven into a rug, either in a small framed box (a cartouche) or directly into the border stripes. It works as a maker's mark that ties the rug to that workshop's standards; signed pieces from famous workshops sell for more and are sought by collectors, and a rug sold under a workshop's signature must truly come from that workshop. Not every workshop rug is signed, and a workshop can stop using its signature. Isfahan rugs and newer Qum rugs usually carry one, while most Nain rugs, silk-foundation Yomut Turkoman rugs and many older Qum rugs do not.
Silk yarn knotted into selected parts of an otherwise wool pile, such as flowers, animals and other pattern details, so those areas shimmer against the wool and the design gains vibrancy and depth. Because silk is finer than wool, it also permits a higher knot density. The device is a hallmark of Nain rugs, where blue or ivory silk picks out different areas of the design, and it is common in Tabriz and some Sarouk rugs. Stains are harder to remove from silk than from wool, so a pile of pure wool is the better choice for a dining room.