Sage and Rose Turkmen Gül Bokhara, Hand-Knotted Wool Rug

100% wool pile, hand-knotted, finished with an ivory fringe at both ends and a washed, low-contrast palette applied in the finishing rather than acquired through age.

This is a pale rug from edge to edge, with no dark ground anywhere to absorb a mark. The borders are the greater exposure — they take more of the surface than the field does and run over 66cm deep on both long sides, sitting exactly where people step on and off. The field is more densely drawn and hides ordinary soiling better. Bear in mind too that anything which shifts the tone of the ground locally will disturb the balance the design depends on, since the field's apparent colour comes from its relationship to the border rather than from the wool itself.

The field of this rug looks green. Measure it and there is no green in it. Sampling only the plain ground, so none of the drawing interferes, the field sits at hue 52 degrees — which is yellow, not green, green not beginning until around 70 — and at a saturation of 0.138, below the level at which a colour registers as having a hue at all. Across the whole rug the green family accounts for 0.76% of the surface.

What produces the sage is the border. Its ground measures hue 29 degrees and saturation 0.233 — twenty-three degrees warmer than the field and half again as saturated. Set a near-neutral beside something distinctly warmer and the eye stops reading it as neutral and starts reading it as the opposite of its neighbour, which is to say cool, which on a pale yellowish ground means green. The colour is not in the wool; it is in the relationship. This is worth knowing before the rug goes into a room, because the effect is not fixed. Put it against warm terracotta walls and the sage will strengthen. Put it on a cool grey floor and the field will fall back towards the beige it actually is.