The Rug Library

Jute's long, rough fibres can be spun into coarse but strong threads, which is why jute yarn gives rugs a sturdy, textured feel.

Eri silk cannot easily be reeled from the cocoon, so it is carded and spun like cotton or wool, giving a durable, textured yarn.

Degumming removes silk's soluble sericin gum, usually in a hot, often alkaline, bath, leaving fibroin filaments with silk's characteristic soft handle and lustre.

Warp yarns are put under more stress during weaving than weft yarns, so they are usually stronger, smoother, more even and more tightly twisted.

Handspun wool varies naturally in fibre and yarn thickness, so different sections take up dye to different degrees, one reason abrash is associated with handspun, naturally dyed yarn.

In a knotted-pile rug, coloured pile yarns are tied around pairs of warp yarns so their cut ends stand up to form the pile, with rows of knots locked in place by tightly drawn weft yarns.

A historical account quoted on Wikipedia notes that eri silk had to be carded and spun, a craft practised in the Khasi Hills of the Northeast long before it was known in Europe.

Cotton warps are valued in knotted rugs because cotton yarn is strong and dimensionally stable, helping the finished rug lie flat.

Silk fibroin has a highly oriented, crystalline structure that makes it insoluble in water and dilute acids or alkalis, whereas the sericin gum around it dissolves readily.