Dyeing the wool is the first step in making an Oriental rug. It is a beautifully simple process. Create a dye bath, boil the bath while whirling the wool in it, drain and dry in the glorious sunshine. Thousands of years of experience and techniques are applied to each batch of dyed wool. It is the first step in how to make a rug beautiful.
Dyed wool gives Oriental rugs the astonishing colours that grows and matures with age. Dyeing wool requires a great deal of skill and precision, this process is an art form. The master dyer, inevitably a man, is a revered and powerful figure in the community. His advice is sought on a range of subjects, particularly those concerning herbs. His secrets of dyeing are well guarded and carefully passed down from generation to generation, father to son.
To start the dyeing process, wool must be carefully and properly washed. After the wool had been spun into yarn, it must be cleaned again to allow dye to fully and evenly penetrate the fibres. The wool is then treated with a chemical mordant to fix the dye. Common mordant are alum, iron, chrome and tin. Depending on the mordant, the colour of dye is altered.
Then begins the actual dyeing process. The skeins of wool are submerged into a dye bath, which is a secret combination created by the master dyer. The dye bath is brought to a boil, while the wool is carefully stirred to ensure uniform absorption. Wool is hung to dry naturally in the sun after the dye bathing. Silk and cotton are dyed in much the same way, using the same kind of dyes.
Natural dyestuff is derived from plants and insects. The former is the more prevalent source. The most common plant dye is the madder plant, which creates a brownish red colour. Indigo is creates clear blue hue; it comes from the indigo plant. Weld, from the weld plant, makes a yellow or gold colour. The skin of pomegranate creates an orange hue. Onion skin creates a yellow or copper colour. Walnut, oak and other nuts create various shape of brown. The most popular insect dye are cochineal for a red hue and Dactylopius coccu cacti for a yellow hue.
The mordant used to fix the dye can dramatically change the colour. For example, an onion skin dye combined with alum yields a golden deep yellow but the same onion skin dye fixed with chrome produce a copper colour. The fluidity of colour dye in the rug making process makes each rug an unique artwork. Any rug made before 1870s are most definitely natural dyed and are extremely valuable for that reason alone.
The truth is synthetic dyed rugs does not mean poor quality rug. It is the quality of the dye that determines the quality of the rug.
1856 William Henry Perkin first invented the aniline dye, which was directly applied to wool with an alkaline solution. Sadly, the colours run easily and bled when washed and faded dramatically when exposed to sunlight.
In the 1870s, the direct acid dye was created. Wool were coloured in an acidic dye bath. It had solved the sun exposure issue but it still bled during the wash. Azo dyes, created in the same period, offered better colours but certain colours still bled.
1940s was a period that applied chrome dyes, which was applied with chromium mordant to fix the colour. Potassium um dichromate was applied to wool to achieve an even application.
Since then, fibre-reacting dyes are the go to synthetic dye method. The colour-giving part of the dye molecule binds with a wool molecule, permitting the dye to become a part of the wool’s chemical structure. It creates a highly colourfast result, but expensive.
There are two ways to determine the quality of dye: the shade and intensity of the colour and colourfastness. The first one is easy to judge. Top quality rug will be attractive, not harsh or faded. Colourfastness, on the other hand, is difficult to determine while buying. You could test colour by lightly rubbing the rug with a moistened handkerchief.
Painting rugs is a fascinating process as a consequence of Persian rug dealers’ attempt to appeal to the Western demand. It started in 1920s and 1930s, when many Persian rugs were considered too bright and garish for the Western market. These rugs were given a chemical wash to soften the colours, then a lustre wash to create a lustrous sheen. Finally a hand-applied painting that darkened the colour. This painting process was followed by yet another lustre wash. Most Sarouks were ‘painted’ in this manner, as were some Mahals, Hamadans, and even some valuable Isfahans. Many valuable antique rugs such as Sarouks were painted. Unless the painting process was poorly applied and blotchy, it does not affect the value of the rug.
However, sometimes the term ‘painted rug’ refer to rugs that have been coloured by ink or acrylic paints to hide the worn areas, also known as a colour wash. It is highly popular today to grey, white or red colour wash rugs, and this creates a mono-coloured rug with traditional design and hand weaved knots underneath. Originally, this colour wash method was considered unethical as it was meant to hide worn areas or rugs that have bled during the wash. However, in today’s market, the coloured wash continue to gain popularity.