Coral Red and Indigo Turkmen Gül Bokhara, Hand-Knotted Wool Rug

100% wool pile, hand-knotted, with a natural fringe at both ends. At this size the rug is light enough to lift and shake out, which is the easiest way to keep it clean.

A coral red ground is reasonably forgiving of everyday marks. The cream inside the güls and border repeats is the vulnerable colour — it is the palest thing here and the first to grey, and on a small rug it sits right where the traffic crosses.

At a glance the dark parts of this rug all look black — the outlines round each gül, the device at each gül's centre, the small motifs threaded through the borders. They are not the same colour. Measured across the field, about a quarter of the dark wool is blue-leaning, with the blue channel sitting some twenty points above the red, while the remaining three quarters runs the other way and is genuinely warm. Two different dark wools have been used, and they have been given different jobs.

The warm near-black does the drawing: it outlines each gül and separates one colour from the next, work that wants a neutral so it does not compete. The indigo is reserved for the centres, where it reads as a colour in its own right rather than as a line. Take the rug to a window and the difference becomes obvious — the outlines stay flat and dark while the centres come up distinctly blue. Under electric light at night the two will look almost identical again, which is worth knowing before deciding where to put it.