In my last article, which appeared in the May issue of ICS, we discussed rayon viscous or artificial silk [REVIEW] that is often assumed by rug owners to be the real deal. This time we will look at silk – a true luxury fiber.
Silk has been woven into tapestries, rugs, fine fabrics and accessories for over 4,000 years. Sericulture (the cultivation of silkworms for silk) has remained virtually unchanged over the centuries.
Silkworms are actually caterpillars, with Bombyx mori the most common. It is raised domestically and feeds on the leaves of the mulberry tree. The silkworm will spin a cocoon (See Image 1) to go through the transformation from the pupa state to emerge as a moth. However, the cultivated silk process does not let the moth emerge from the cocoon as they are steamed to kill the pupa. This keeps cultivated silk as a continuous fiber. The fiber of one cocoon can be up to 3,000 feet, or 900 meters. The cocoons are then immersed in boiling water (See Image 2) to remove the sericin (a gummy-like substance that hold the cocoon together) then reeled on to bobbins (See Image 3). The silk is spun into yarns or threads for weaving into fabric or making a hand-knotted rug (See Image 4).
A lot has changed in the silk rug market since this topic was last looked at, which was all the way back in the September 1999 issue of ICS. Due to the high labor cost of producing silk, China and Turkey have substantially decreased the amount of hand-knotted silk rugs. Egypt, due to the recent political upheave, has all but disappeared from the market along with Kashmir. Some silk production continues in Thailand, but not rug weaving.
Persian silks have been woven for decades with some of the best from Tabriz, Heriz, Kashan and Kirman. Recently, the main production is in the city of Qum. Quality varies to a surprising degree and each rug should be examined for workmanship, fineness of knotting, design and stability of dyes.
The colors of Qum rugs are rather limited, with dark blue, pale gold, salmon pink, ivory, green and brown as the main colors. Patterns will vary from prayer rugs and hunting carpets to medallion designs. Sizes vary from 30” x 20” to 12’ x 9’.
Persian silk rugs found in the U.S. would have been imported before the current embargo that began in September 2010. Prices of silk rugs in Iran (and the U.S.) have skyrocketed due to local and international demand. A Qum dozar (a rug about 6’ x 4’) in good condition will retail anywhere from $6,000 to $8,000. At $300 per square foot, you do not want to have problems with a silk rug.
So what should a new rug cleaner do? Silks are tricky to clean, and with values going up, “mistakes” are more expensive than ever. My advice is simple – don’t clean silks unless you’re absolutely sure you know what you’re doing. I receive about 3 to 4 calls a month regarding damaged silk rugs from improper cleaning. (See Image 5 – Qum rug with dye bleed). If you do not know your rug ID and can’t tell a Qum from a Tabriz, you should not be cleaning a Qum or Tabriz. Cleaning silk rugs is more than just knowing the fiber.
Instead, find an established rug cleaning plant where you can bring your silk rugs.
If you have some rug cleaning training and a rug cleaning facility then you could attempt low-moisture cleaning. Next, to dye bleed silk rugs can have severe pile distortion issues. Hand-knotted rugs are not manufactured to a government standard. You may have cleaned one successfully in the past but that does not mean continued success with other silks.
The safest way to dust a silk rug is with a pneumatic dusting tool (See Image 6). Dusting with a rug beater can damage the foundation of thin worn silks. Use low-moisture cold-water extraction. Always pull the wand from the top of the rug toward the bottom (with the pile). Never move the wand back and forth. Use a WoolSafe® cleaning product and fiber rinse in the tank of the extraction machine. Silk rugs tend to dry stiff. This could be due to some sericin still in the fiber. Groom the pile toward the bottom of the rug and dry flat (See Image 7). The next day set the pile “up” (See Image 8).
And as previously warned, be sure to use caution when venturing into this specialized area of rug cleaning.