Knot counts, and the point at which they stop mattering

Knots per square inch measures resolution. More knots mean finer detail, curved lines that actually curve, and the ability to render a face or a leaf rather than a suggestion of one. It also means exponentially more time: doubling the knot count roughly quadruples the months at the loom.

A high knot count is not a measure of quality. It is a measure of how much detail the design required.

This matters because a great deal of the finest weaving in the world is deliberately coarse. A Moroccan Beni Ourain at 60 knots per square inch is doing something no 900-knot Hereke can do — a deep, springy, hand-spun pile in undyed wool, made to be sat on in a cold house. Weaving it finer would make it worse.

Match the count to the design

• Geometric and tribal patterns: 60–160 KPSI. Straight lines need no resolution, and a coarse pile wears beautifully.
• Village medallions and all-over florals: 160–300 KPSI. Enough to draw a curve without labouring the point.
• City workshop florals: 300–500 KPSI. Isfahan, Nain, Tabriz — where the drawing genuinely needs the resolution.
• Pictorial and pure silk: 500–900 KPSI. Portraits, calligraphy, hunting scenes. Years of work.

The honest test is to ask what the design is trying to do, and then whether the weave lets it. A coarse carpet attempting fine florals looks muddy. A fine carpet given a simple geometric grid has wasted a year of someone's life on resolution nobody will see.

What actually predicts a long life

Wool quality, and it is not close. Hand-spun wool from a high-altitude sheep, with the lanolin left in, will outlast machine-spun wool at twice the knot count. Run your palm across the pile: good wool feels slightly waxy and springs back. That is the number nobody prints on the label.