How Is a Tapestry Made? Pictures Built Thread by Thread

All woven cloth consists of warp threads held taut on a loom and weft threads passed across them. In ordinary weaving the weft runs the full width and the colour pattern comes from the sequence of threads. In tapestry weaving the weft is discontinuous: each colour is carried on its own small bobbin and worked back and forth only across the region where that colour appears, then turned and worked back. The weft is packed down tightly so that it covers the warp completely, which is why a tapestry shows no warp on the surface and why the design reads identically as a picture rather than as a pattern of interlacing. The warp therefore contributes strength and nothing visual, and the fineness of a tapestry is measured in warp threads per centimetre, with coarse work at around five and the finest at more than twenty, which determines how much detail is achievable.

The process separates the designer from the weaver completely, which is why tapestries are catalogued under two names:

• •A painter produces a small design, and it is then enlarged to full size as a cartoon, a painted or drawn guide the exact dimensions of the finished piece; Raphael's cartoons for the Sistine Chapel tapestries survive and are treated as major paintings in their own right
• •The cartoon is placed beneath or behind the warp so the weaver follows it directly, and on a low-warp loom it is traced onto the warp threads themselves
• •Weaving usually proceeds sideways, with the design turned ninety degrees, because vertical slits between colour areas weave more easily than horizontal ones
• •On a high-warp loom the warp is vertical and the weaver works from the back, checking the front with a mirror; on a low-warp loom it is horizontal and treadles speed the work
• •The weaver interprets the cartoon rather than copying it, choosing how to blend colours, which is why the same cartoon woven twice gives noticeably different results
• •Because weaving from the back reverses the image, published designs and finished tapestries are frequently mirror images of each other

Discontinuous weft creates a structural weakness at every boundary between two colours. Where the boundary runs along the warp direction, the two colour areas turn back on adjacent warp threads and never interlock, leaving a vertical slit. Weavers solve this in several ways: sewing the slits closed afterwards, which is the common European practice; interlocking the two wefts around a shared warp thread; or dovetailing them so they alternate around one thread. Curved and diagonal boundaries avoid long slits naturally, which is one reason tapestry design favours flowing outlines. Shading presents a second problem, since there is no way to mix paint, so gradations are produced by hatching, interleaving fine tapered strips of two colours so they optically blend, a technique developed to an extraordinary level in Flemish work. Metal thread, gold or silver wrapped around a silk core, was woven in for highlights, and a great deal of it has since been picked out and melted, damaging many surviving pieces.

In the fourteenth to sixteenth centuries a major tapestry set cost more than a painting by any master and frequently more than a building, because it consumed enormous quantities of wool and silk and years of skilled labour. That expense made it a statement of wealth, and its portability made it a practical one: a ruler travelling between residences carried the tapestries, hanging them to transform a bare stone hall, insulate it and announce whose hall it was. Sets told stories across multiple panels, drawn from scripture, classical myth, chivalric romance and dynastic history, and functioned as visible political argument about legitimacy and lineage. The great production centres were in Flanders, above all Arras, whose name became a word for the hangings themselves and is what Polonius hides behind in Hamlet, along with Tournai and Brussels, and later the royal Gobelins manufactory in Paris and Mortlake in England. Demand collapsed in the eighteenth century as fashion turned to painted decoration and wallpaper.

Tapestries are among the most fragile large objects in museum collections because they are heavy textiles hung by their own weight. Gravity pulls continuously on the upper edge, distorting the weave and eventually tearing it, so conservation practice now includes supporting the full weight across a lining and rotating pieces off display. Light causes irreversible fading, and because dyes fade at different rates the colour balance shifts as well as dimming, which is why the reverse of an old tapestry frequently shows brilliant colours the front lost centuries ago and why display lighting is kept very low. Wool and silk are food for moths and carpet beetles, so pest management is constant. Many pieces have been cut down to fit walls, had their metal thread removed, or been crudely repaired with mismatched wool. Conservation is correspondingly slow and expensive, with major projects on single hangings running for years, and the accepted approach now favours stabilising what survives over restoring the appearance.

In a tapestry the picture is woven rather than applied, using weft threads that travel only across their own patch of colour and are packed down to hide the warp completely. A painter supplies a full-size cartoon and a weaver interprets it, usually working sideways and from the back, so finished pieces are frequently mirror images of the design. Slits form wherever two colours meet along the warp and must be sewn or interlocked. The cost of wool, silk and years of labour made tapestries the most expensive furnishings in Europe.