The basic design of most Oriental rugs consists of a field framed by a border. Usually the field has either an all-over pattern or a central medallion often supported by segments (or spandrels) which look like curtains at the four corners of the field. The border typically includes one main and two or more minor borders with motifs and colors that can either reflect the pattern in the field or the central medallion, or on the contrary contrast with it. Other less common designs include pictorial representations and more recently free-style designs inspired by modern arts.
The motifs that populate the field and borders in an Oriental rug can range from realisitc to stylized renditions of nature to purely abstract forms and infinite variations in between. See for example the diverse renditions of the "boteh" motif.
In the illustration below, the rug has a red field (I), a blue main border (II) with three minor borders on each side, a central medallion (III) with a pendant above and below, and spandrels (IV) at the four corners which mirror the design and colors of the central medallion.
Like wine, oriental rugs are not finished once they're off the loom. Young rugs of good quality are fresh and clean, their colors vibrant, albeit often clashing against one another. Over time the wool pile acquires a patina, while the colors mature and mellow, and evolve subtle variations that were not previously apparent, blending with the wool fibers and each other to create wonderful harmonies. It is the irregularities and imperfections of the hand-weaving and hand-dyeing process, the human element, combined with the natural material of the rug that eventually give rise to these beautiful variations.
Oriental rugs are made from wool hand-knotted on a grid-like foundation which itself can be of wool or cotton. More rarely the pile and/or the foundation are made of silk. Rug weaving techniquesare well described elsewhere. Suffices to say here that the finer the weave (i.e. the smaller the knot), the more work involved and the greater the detail. Very simply, a rug with 200 knots per square inch requires double the work of a rug with 100 knots per square inch. Think of an Oriental rug as a mosaic and the knots as pebbles--the smaller the pebbles, the finer the detail.
The yarn used in older rugs is spun by hand and dyed in natural pigments derived from vegetal products (plants, roots, fruits) or insects (cochineal). Industrialization at the turn of the 20th century introduced machine-spun yarns and synthetic dyes which permitted a wider, and in the case of Chinese art-deco rugs, wilder, palette of colors. The synthetic dyes were at first of poor quality and prone to running and fading. Later improvements made them fast to light and difficult to differentiate from vegetal dyes, but purist collectors still prefer natural dyes.
The following describes some basics on Oriental rugs, how they're made, the material used, the design and patterns.