Knot density

Number of knots per unit area is directly proportional to the quality of carpet.

For two carpets of the same age, origin, condition and design, the one with the higher number of knots will be the more valuable.

A rug could have a knot density half that of another yet still be more valuable, KPSI is only one measurement of quality and value in Persian carpets.

In those with a low knot density (as well as kilims), simpler, rectilinear, motifs tend to prevail.

A carpet with a lesser knot density is better adapted to bold, geometric designs and can utilize a long pile for softer, more reflective surface that appeals to the sense of touch.

More difficult patterns with an above-average knot density can only be woven by a skillful weaver, thus increasing the production costs even more.