The harmonious and radiant colors of the Oriental rug are among its major attractions. It is the richness of the color scale that allows for the magnificent decorative effects.
Prior to the 20th century, traditional dyes -- derived from plants and animals -- were employed. Recipes were handed down from generation to generation. One of the most important coloring agents was from the madder, a common plant that grows wild in Persia. From the root of the madder came dye for various shades of red and pink. When combined with a mixture of milk and fermented grape juice, the madder root yielded a violet dye. The bright red cochineal insect also provided red dye, as did the kermes insect that lives in the bark of oak trees.
Wild saffron provided a reddish-yellow, while cultivated saffron offered a pure yellow. A lighter yellow came from the root of turmeric. A fungus of the mulberry bush provided a green-yellow. The soaking and fermentation of indigo plants from China and India provided blue. The infrequently used black dye came from iron oxide, and it was the only dye of mineral origin. However, the acid substance obtained from soaking iron shaving with vinegar can have a corrosive effect on wool. Brown dyes could be made by mixing madder with yellow or from the shells of green walnuts, gallnuts and
valonia. The brown dyes sometimes had a tendency to dull with age.
The most successful and widely used colors in Oriental rugs are reds, yellows and blues. Red is probably the most popular of all colors and is a favorite of Turkish and Turkistan dyers. Yellow and dark green are used extensively in Persian carpets. And blue is frequently seen in Caucasian fabrics, particularly those from Armenia.
Yarn was not dyed in the skein; instead, each long strand was plunged into the dye. The yarn then was dried in the open air and eventually was exposed to sun and dust. This system imparted to the shades of different strands an endless number of gradations. And these gradations made a woven carpet vibrantly come to life.
Around 1870, controversial synthetic dyes came to the coastal regions of the East and eventually worked their way to the nomadic peoples. Particularly for shades of red, the synthetic aniline dyes proved more economical to use than natural dyes. And aniline dyes allowed carpet-makers to speed up production and meet increasing product demand.
Aesthetically, however, the chemical dyes had limited success. Natural dyes mellow with age, while synthetic dyes fade. In some cases, synthetic dyes completely change color over time. It has been said that naturally dyed carpets become more beautiful with time, but synthetically dyed carpets deteriorate with time.
In an attempt to stem the invasion of chemical dyes, Persian sovereign Nasir-ud-din (1848-1896) ordered that all aniline dyes be destroyed. In addition, rugs made with the artificial dyes were confiscated. But smuggling prevented the strict application of these measures. The laws eventually were modified so that rugs with artificially dyed threads were penalized with an export tax.
Since 1920, natural dyes have virtually disappeared from the making of Oriental rugs. The use of synthetic dyes remains controversial. Some say the aniline dyes have been greatly perfected and offer every guarantee of quality. Others say aniline dyes, over time, dry the carpet fibers making them brittle and fragile and seriously diminish the value of modern Oriental rugs.