Before you buy a rug, check its roots

Anyone who has ever shopped for an Oriental carpet has wondered whether that handsome rug is exactly what the dealer says it is.

Fine antique Orientals made with natural dyes and knots of hand-spun wool are worth their four-, five- and sometimes six-digit price tags. Newer carpets made with chemically dyed wool are rarely their equals.

Today’s Oriental rug collectors, just like collectors for generations, prize natural, vegetal dyes.

Western craving the rich, saturated colors created by the plant- and insect-based dyes in Oriental carpets drove a brisk trade in these precious weavings as far back as the Middle Ages.

But starting in the second half of the 19th century, labor-saving chemical dyes spread rapidly throughout the tents, villages and workshops of traditional weavers from Turkey to China.

Almost overnight, the more expensive and time-consuming process of using natural dye stuffs was forgotten.

By the start of the 20th century, the old natural palette could be reproduced using chemicals.

Unfortunately, the early synthetic dyes were neither water- nor light-fast, and the colors faded and bled. The modern chrome dyes widely in use since World War II present the reverse problem. The colors are so perfect that they lack the depth and warm hues of the older, naturally dyed carpets.

In the early 1980s, a German chemist named Harald Bohmer deciphered the old natural dye recipes, instantly spawning a renaissance.

There is no foolproof method, short of chromatography, to tell the difference between chemical and natural dyes.

But there are a number of simple ways for consumers to judge what they’re buying.

Antique carpets

Examine the carpet’s pile: Look closely for fading at the top of the pile. If the roots are darker than the ends, you’re most probably seeing chemical dyes.

Check the carpet back: If the colors on the back of the rug are brighter than the pile, chances are the dyestuff was chemical and faded over time when exposed to light.

Beware garish colors: Bright, solid oranges and greens are most likely chemical, especially if there is no variation in the color. In naturally dyed wool, both are secondary colors made by dyeing the wool with one shade and then a second. That process leaves flecks of the primary colors.

Look for abrash: Wool dyed with vegetal materials will almost always have variations. This variation in color, caused by the imperfect nature of natural vat dyeing, is called abrash and is a mark of pedigree. If a color in the rug is completely uniform or monochromatic, with no subtle changes in shade, you’re seeing the perfection of modern chemistry.

New carpets

Judge the colors: Just as with antique rugs, it’s all in the colors. Are the colors harsh, too shiny, tinny or unusual? Are they too uniform without subtle variation or abrash? Then they are likely the product of chemical dyeing.

Check rug size and age: You won’t find a room-sized Oriental carpet made after World War II and before the natural materials renaissance that started in the 1980s that has naturally dyed wool.

Check the provenance: Many rugs made today advertise all natural dyes. If a dealer makes that claim, ask who made the carpet. If the dealer can’t name the producer, chances are the rug was bought in a wholesale market and is chemically dyed. Reputable modern producers making rugs the old way will almost always have their brand-name tag on the rug. You’ll be able to investigate the company on the Web.

Check the price: Natural methods are expensive. Although a new room-sized carpet won’t cost nearly what a comparable 100-year-old one will, a quality new rug can easily carry a $5,000 to $10,000 price tag.

In the end, there is no rush. Reputable dealers always allow you to take a rug home to see how it looks on your floor before you agree to buy it.

Chris Fager teaches a class on the art of the Oriental carpet at UCLA Extension.