Key to Ancient Carpet's Magic was Bugs, Plants

There really is a magic carpet, you know. It doesn’t fly, but it can let your imagination soar.

So, imagine this. The year is 1949 and Russian archeologist Sergei Rudenko comes upon an ancient tomb during an archeological dig. No treasures were to be found, grave robbers having long ago absconded with them. But in the corner lies a carpet, probably judged to be of no value by the thieves. Rudenko can’t believe his eyes when he examines the find. The brilliantly coloured carpet has been perfectly preserved by the Siberian cold! He knows it is old, but not until the fabric is radiocarbon dated does the archeologist realize that he has come upon the earliest known carpet, dating back to roughly 500 B.C.!

Named after the valley where it was discovered, it would come to be known as the “Pazyryk Carpet.”

It boggles the imagination that 2,500 years ago, artisans managed to produce brilliantly coloured threads of wool and silk despite lacking any formal knowledge of chemistry. How did they do it? Bugs and plants, that’s how!

The dominant colour of the Pazyryk carpet is scarlet, which chemical analysis has shown to be derived from the female kermes insect. These insects spend their lives attached to the appropriately named “kermes oak,” with the unlucky ones being scratched off with fingernails, destined to be drowned in vinegar before being dried and ground up.

The Sanskrit term for kermes was krim-dja, from which we derive our word “crimson.” So prized was the kermes insect in antiquity that the Romans sometimes demanded taxes be paid in sacks of kermes.

Plants furnished the other colours seen in the Pazyryk carpet. Blue was derived from the indigo plant, while the yellows and browns were extracted from saffron or turmeric. Green was probably a combination of yellow weld and blue indigo. Such natural dyes continued to be developed through history and were the mainstay of the carpet industry until the 19th century.

A greenish yellow was obtained from a fungus that grew on the mulberry bush, red came from the root of the madder plant, brown from walnut shells or pomegranate peel, purple from hollyhocks. Black was a problem because the process to obtain it required soaking iron shavings in vinegar, and this produced a dye that had a corrosive effect on wool.

One of the most attractive features of these natural dyes was that each carpet was unique. The colouring process

never produced exactly the same shades. Since each strand of the carpet was dyed individually, the strands had a variation of colour even when dyed in the same mix.

All of this changed dramatically in 1856 with William Henry Perkin’s discovery of synthetic dyes. A whole range of hues never before seen could now be provided by compounds synthesized from coal tar isolates.

The “aniline dyes” took their name from aniline, perhaps the most famous of the compounds isolated from coal tar. These dyes were far cheaper to produce and easier to work with than the natural dyes. But in the eyes of most, they did not provide the same warm colours and individuality. It was said that a carpet made with synthetic dyes had no personality, it was identical to any other produced the same way. Furthermore, the synthetic dyes did not stand up well to water and faded on exposure to light.

While the chemical community celebrated Perkin’s discovery, Mozaffer ed Din, who became Shah of Persia in 1900, was no fan of the novel synthetics. Indeed, one of his first edicts was to prohibit the use of aniline dyes for the famed Persian rugs. All such dyes were to be seized and publicly burned. Penalties for their use included jail time and fines equal to double the value of the merchandise.

Sounds like a curious edict. Why did the Persian ruler care about how carpets were dyed? Because carpets are an integral part of Persian culture, having been woven into the fabric of Persian society for more than 2,500 years.

Persian carpets are regarded as the finest in the world, and the shah believed that this reputation was about to be compromised by the introduction of synthetic dyes. And there was quite a reputation to be concerned about, perhaps best exemplified by what is regarded to be the most magnificent rug in the world, the “Ardabil Carpet,” woven for Shah Tahmasp in the 16th century. On display in London’s Victoria and Albert museum, this silk and wool carpet features 10 different colours and more than 26

million hand-tied knots! Its unique design has fostered endless copies, including one that adorned Hitler’s office in Berlin.

While Mozaffer ed Din may have stalled the use of synthetic dyes, he was unable to stop the march of time. By the 1920s, a new class of synthetics, known as the chrome dyes, had been developed. The critical component was sodium dichromate, used as a mordant. Mordants are chemicals added to a dye solution to forge a strong link between the fabric and the dye, producing long-lasting colours that can compete with the natural dyes.

Today, most Persian rugs are made with chrome dyes, although there are still some villages where carpets with natural dyes are being produced. Connoisseurs value these highly because no two are alike. Indeed, it may well be the beauty of such rugs that inspired the association with magical properties.

The most magical of all the rugs, The Pazyryk Carpet, is now one of the prized exhibits at St. Petersburg’s Hermitage museum. It is securely locked in a glass case. Definitely a no-fly zone. But people who had sat on the rug before it was placed in the Siberian tomb may have flown. Beside the carpet, the archeologists found some pipes and a supply of hemp seeds.

http://www.montrealgazette.com/technology/ancient+carpet+magic+bugs+plants/3292509/story.html