What to Look for When Buying a Persian Rug

The Basics

• Traditional Persian rugs are hand-woven on looms, beginning with threads running from top to bottom, called "warps," then woven from side to side, called "wefts." This foundation is usually woven from cotton to give it strength. A weaver then ties the wefts together with knots made of wool, cotton or silk. Since each knot is hand-tied, it can take a weaver up to six months to make a rug measuring 9 by 12 feet.

  The quality of the materials used is one of the factors to consider when buying a rug. Other factors include the number of knots per square inch, the type of dyes used, the intricacy of the design and, when buying antique rugs, the condition and age.

Materials

• The designs used in antique rugs are often handed down from one generation to the next. Most designs originated with tribal symbols that were modified by weavers over the years until their original meanings were lost. Designers gradually began to include floral and pictorial motifs. Modern Persian rugs, which are made only in Iran, are produced using both modern methods, with synthetic yarns and chemical dyes, and traditional methods, using tribal motifs and vegetable dyes.

  Rug yarns can be spun from sheep or goat's wool, cotton, silk or a combination of these materials.
  The wool used in the rugs can vary greatly in quality. The highest-quality sheep's wool comes from Tibet and New Zealand.

  Modern rug-makers use chemical dyes, which are colorfast, reliably uniform and durable but don't have the soft appearance of vegetable dyes. In addition, traditional dye-makers prepare their dyes in small batches and variations in shading exist among batches. This uneven tonal quality is characteristic of antique rugs and has come to be valued as an integral part of their beauty.

Buying Tips

• As a general rule, a high number of knots per square inch indicates a higher-quality rug. This is especially important for finely-detailed floral or pictorial designs and less important for large geometric designs. Turn the rug over and look at the back, where the undersides of the knots are apparent.

  Persian rugs characteristically appear lighter when viewed from the top end and darker when viewed from the bottom end. Since the knots are pulled downward as the yarn is cut, the pile has a distinctive downward slant. More light is reflected from the top edges of the yarn, giving it a lighter appearance. Less light is reflected from the bottom edges of the yarn, giving it a darker appearance..

  If you're buying an antique rug, be sure you're dealing with a reputable seller. Avoid clearance and going-out-of-business sales and traveling auctions. Examine the rug for signs of wear and repair. A soiled rug can be hiding wear. A professionally-made repair won't affect the rug's value but a sloppy one will.

  Whether you're purchasing a new or antique rug, take the time to acquaint yourself with the varieties of design. Most Persian rugs have some common elements such as the background, or "field," and the edging, or "border." Some designs feature an overall pattern, while others have a larger design element in the center, known as a "medallion." If you're going to place furniture over the center of the rug, you probably won't want a central focal point.

  If you're buying a new rug, be aware that it's probably not a one-of-a-kind design as are antique rugs. Buy the rug for its decorative purposes rather than as an investment.

  Know the dimensions of your room when you shop. Persian rugs are traditionally used as area rugs, with two or three feet of floor showing around them. Decide where you'll be placing the rug and subtract footage accordingly.

  When you decide on a rug you want, live with it for a few days. Ask the seller to let you take it home before you buy. Put the rug in your room and notice how it looks in daylight and artificial light and whether it harmonizes with your furniture, walls and accessories.