Instructions
Look at the way the rug has been made. Vintage Oriental rugs are hand-knotted --- that is, they are formed upon a loom by knotting woolen threads onto a cotton warp. The knots are gathered in lines across the width of the rug, with the result that the long sides show slight irregularities. Unlike machine-made rugs, the design of a hand-knotted rug should be clearly legible on the underside. Earlier examples of Oriental rugs tend to have a higher knot density, so when seeking out a genuine antique, check for small, fine knots packed closely together.
Consider the rug's coloration. Many 20th century rugs make use of artificial Western colorants that produce relatively strident results. By comparison, earlier rug-makers drew on a range of natural dyes --- the cochineal bug for red, vine leaves for yellow, copper sulphate for green. Black could be achieved simply by using the wool of black sheep. Look for soft, muted colors and tones that have a certain individuality compared to other surrounding rugs. These characteristics convey signs of age.
Check the size of the rug. Examples made in villages on traditional horizontal looms will be no more than 9 feet in length, as this is the maximum the loom can accommodate. A greater size indicates the use of a modern and sophisticated loom, and would therefore suggest that a rug is of more recent origin.