Colour is the most reliable dating evidence a Persian rug carries, and the place where age claims most often fail.
The dyestuffs
- Madder root
- The dominant red. Ages towards brick, never towards brown.
- Cochineal
- Insect-derived crimson. Costlier, bluer, used more sparingly.
- Indigo
- The only historical blue. Abrades lighter at the pile tip.
- Weld / vine leaf
- Yellow. The least lightfast dye in the palette.
- Walnut husk
- Brown. Stable and common in undyed-adjacent tones.
- Iron / oak gall
- Black. Corrodes wool over decades.
Two of those produce effects you can read directly on any old rug.
Green drifts blue. Persian green is indigo overdyed with yellow. The yellows are far less lightfast, so as they give out the green moves towards blue. A rug that is blue-green in the protected areas and blue where light reached is aging honestly.
Black wears low. Iron-based blacks chemically attack the wool they colour, so on an old rug the black outlines are frequently worn below the surrounding pile. You can feel the relief with a flat hand, and it is very hard to fake convincingly.
The regional palettes
| Region | Characteristic palette |
|---|---|
| Kashan | Deep madder red field, indigo spandrels, ivory detail |
| Isfahan | Ivory ground, restrained blues, sparing red |
| Nain | Ivory and light blue, silk outlining |
| Tabriz | Very wide; modern production leans ivory and soft blue |
| Heriz | Brick red and strong indigo, high contrast |
| Kerman | Soft rose, ivory, pastel range unusual for Persia |
| Qashqai | Saturated madder, indigo and undyed wool |
| Baluch | Aubergine, camel, blue-black — the darkest palette |
Kerman is the outlier worth knowing. Its pastel range was developed substantially for the American market in the early twentieth century, so a soft-pink Persian rug is more likely to be export production than nineteenth-century domestic weaving — antique rugs.
Abrash
Horizontal banding where the weaver moved to a new dye lot. It is a consequence of small-batch dyeing, it is characteristic of hand weaving with natural dye, and it is desirable rather than a fault.
It is most visible in indigo grounds, because vat depth depends on dip count and varies easily. The chemistry is covered in blue Persian rugs.
Modern production sometimes simulates it, so treat abrash as supporting evidence rather than proof.
Reading the pile
Base against tip
Bend the pile back along a knot row. Natural dye is usually richer at the base, where light never reached, and softer at the tip. A strand identical from base to tip means either a young rug or one that has been chemically washed.
Chemical washing to soften colour for export is routine and long-standing. It is not fraud, but it removes the gradient that would otherwise tell you about age.
Fading and care
All rugs fade. What matters is whether they fade evenly. A rug half in afternoon sun develops a permanent line; rotating 180 degrees twice a year prevents it entirely — see caring for Persian rugs.
A damp white cloth pressed on a saturated colour should pick up nothing. Any transfer means unstable dye and a professional cleaning job.
The general dye chemistry is in rug colors; how colour sits among the factors that drive price is in what Persian rugs are worth.
Common questions
Why are so many Persian rugs red?
Madder root grew across the region, produced a stable, deep and lightfast red, and was affordable. Availability drove the palette more than symbolism did — the dominant colour of a weaving tradition is usually the dyestuff that grew nearby.
Does a faded Persian rug lose value?
Even, gradual fading of natural dye is desirable and adds value — it is what collectors mean by patina. Uneven fading from one-sided sun exposure is damage and reduces value. The difference is whether the whole rug aged together.