neat back and dense knots

This picture shows the neat back of 260 lines silk Persian silk rug z185286. The knots are very clear and dense, evenly laid out and they are
very tied.
There are 22 lines of knots per inch and there are 470real tied double knots per square inch. For this quality hand-knotted silk
rug, each person can make around 2.25 square feet per month.