Colours and dyeing
Before a rug is knotted, the wool has to be dyed. Whether the dyestuffs are plant-based or synthetic shapes the rug's whole appearance and how its value develops. This page sets out the most important natural dyes, their sources, and the marks they leave in a rug.
#Plant dyes versus synthetic dyes
Until the late 19th century, dyeing was almost entirely with plant dyes. In 1856 the English chemist William Henry Perkin invented the first synthetic dye, and over the following decades aniline and later chrome dyes pushed natural dyes almost completely aside.
High-quality contemporary workshops, especially in the revival movement of the 1980s (think DOBAG in Turkey, the Gabbeh renaissance in Iran), turned back to plant dyeing.
Both methods have their own character. Plant dyes are livelier in tone, because they never come out perfectly even. Synthetic dyes are more reproducible and noticeably cheaper, but often look flatter and age less gracefully.
#Madder: the warm red
Photo: Wikimedia Commons
Madder is the root of the dyer's madder plant (Rubia tinctorum), a plant from the Mediterranean and Western Asia. From the dried and ground roots a deep, warm red has been won for over two thousand years.
Depending on the mineral content of the water used, the mordant (often alum), and the dyeing time, the result ranges from pale pink through coral and brick red to deep bordeaux.
Madder is exceptionally light- and wash-fast and ages especially well. Over the decades the red darkens slightly and gains a characteristic depth that synthetic reds cannot match. Most antique Persian rugs have their red ground dyed with madder.
#Indigo: the deep blue
Photo: Wikimedia Commons
Indigo is the dyestuff of the indigo plant (Indigofera tinctoria), grown in India, Persia, and Egypt for thousands of years. Dyeing with indigo is laborious. The plant is fermented, the resulting yellowish brew takes up the wool, and only through oxidation in the air does the characteristic blue develop.
Wool has to be dipped in the brew several times. Each dip deepens the colour by one step. This produces the famous indigo scale, which runs from a pale powder blue to nearly black night blue.
Indigo is similarly light- and wash-fast to madder and ages just as well. A real indigo dye gives itself away through the uneven, almost living variation in the blue, which looks different at different angles of light.
#Walnut, weld, oak galls
Alongside madder and indigo, classic dyers work with a whole series of further plants.
Walnut hulls give warm browns, from light beige to mahogany, depending on concentration. Weld (Reseda luteola) yields a bright, light-fast yellow that often shapes the ground of Caucasian rugs. Oak galls, formed on oak trees by wasp stings, give deep blacks and greys.
Pomegranate skins yield yellow to olive green. Cochineal (a scale insect from Mexico, rarer in oriental rugs) gives a clear, cool red that sets itself apart from madder.
From these base colours, through mixing and overdyeing, come the hundreds of nuances of a classic naturally dyed rug.
#Abrash: the lively variation
Abrash is the trade term for visible colour shifts within a supposedly single-coloured area of a rug. The term comes from Arabic and means roughly "speckled".
It arises because a wool batch is never fully homogeneous before dyeing, and because separate dye lots never come out one hundred percent identical. When the knotter switches mid-rug to a new strand from a slightly different lot, you see a soft, often horizontal shift in tone.
In hand-knotted tribal rugs, abrash is almost always present. In fine workshop rugs it is deliberately avoided, but with naturally dyed pieces it can never be fully ruled out. Unlike machine-made rugs, which are visually completely uniform, abrash is regarded today as a mark of authenticity and quality. It proves handwork and natural dyeing.
Anyone who buys a rug with lively abrash buys a rug that breathes.
#What you can read from the colour
Three simple tests separate real plant dyeing from synthetic.
First: look at the rug from different angles. Natural dyes shift subtly with the light. Synthetic ones stay rigid.
Second: look for abrash, the slight variations in supposedly single-colour areas. With a tribal rug that shows no abrash, be suspicious.
Third: compare front and back. With good natural dyeing the colour runs through the wool to the core. With cheap synthetic dyes only the surface is coloured, and the core of the wool fibre is noticeably lighter.
What you do not strictly need: a water test. Real natural dyes can crock slightly under heavy rubbing, especially madder and indigo. That is not a flaw but a sign of authenticity.
Keep reading
Materials for oriental rugs
Wool, silk, cotton, jute, and synthetic fibres. What sets each apart, what it suits, and how it feels.
ReadHow oriental rugs are made
How wool, silk, and natural dyes become a hand-knotted work of art — explained step by step.
ReadIdentifying oriental rugs
The key markers to distinguish a genuine hand-knotted oriental rug from imitations.
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