If you are looking for a perfect, symmetrical, uniform-looking rug you should probably check out machine made rugs. A while ago, someone asked me why her Persian rug looked different from one end to the other. Like anything else made by hand, there will be imperfections in authentic Oriental rugs. Granted, some of those imperfections may be intentional, and some may be more pronounced than others.
A Machine Made rug with an Oriental rug design.
Tribal rugs woven on horizontal looms in village settings are more likely to have imperfections than those woven on vertical looms in the cities or workshops where weavers strive for perfection.
Above is a hand knotted Persian Joshaghan rug. Note how the sides of the rug are not perfectly straight and the design is not completely uniform. For many customers and rug lovers these are the characteristics which drive the sale of the rug. Each imperfection adds to the one of a kind nature of an antique Oriental rug such as this.
One of the most common occurrences of “flaws” in authentic Oriental rugs is abrash. Abrash is a term used quite often in describing the characteristics of a rug. It refers to a change in the tone of the color of the wool in a specific area of the rug. For example, a field may be dark blue with a thick line of lighter blue running horizontally across it. It is easy to confuse abrash with fading. Fading is a result of long-term exposure of a rug to the sun, and some fading can occur due to wear depending on the dyes used in the rug.
The rug pictured above has notable abrash at one end. Note how the band runs horizontally along the same path a weaver would be tying the knots onto the foundation. This type of variation in color would not be called fading because fading is uneven and it would be very difficult to achieve this look after completion. Abrash occurs when the weaver changes wool lots, most often because the last lot has run out, and the next lot of wool may be lighter, or darker due to any number of variables including the dye time, temperature, and type of mordant among others.
Another common flaw in Oriental rugs is white knots appearing in the field, especially after the rug has seen some traffic. These knots are the tail ends of the foundation as seen below.
Knot tails in a Turkish Sparta rug
What type of unique imperfection does your Oriental rug have?