Textile Structure
how cloth is put together
Concept

Crease — where it appears

A fold pressed into a cloth sharply enough that its crimp cannot supply the extra length the outer face needs, so the fibres are strained instead. It is the one fold radius at which the bending bracket collapses to a single branch, because the coherent branch would strain a cotton fibre by eighty-four per cent and cotton breaks at six.

Named by 4 essays across one field — each of them below, with the objects they name alongside it.

A cotton yarn at a fold, at both ends of its bending bracket. The same 20 tex cotton yarn bent to a radius of 0.084 mm under the two assumptions this site's bending bracket is drawn between. If the fibres slide freely past one another each bends about its own middle and the surface strain is 7.14%; if they are locked the bundle bends as a rod and the outermost fibre is strained 100%. The ratio is 14.0, which is the ratio of the two diameters and therefore the square root of the fibre count over the packing — so the bracket of 327 this site carries in a stiffness is a bracket of 14.0 in a strain. What the drawing cannot show is which of the two a real yarn does, and the answer is settled by a refusal: at the tightest fold a cloth can make, the locked bound asks for a strain of one, and a creased cloth does not fall apart.

A wrinkle cannot settle what a crease settles

The first rung of this ladder found that a pressed crease decides a question this collection had been unable to settle for two fields — whether a bent yarn's fibres slide or bend as one body — and it decides it by refusing: the coherent branch would strain the fibres by eighty-four per cent and cotton breaks at six. A wrinkle is the same fold at twenty times the radius, and there both branches are survivable. So the bracket that a crease collapses stays fourteen times wide at every radius anybody actually creases a cloth at accidentally.

finishing · Crease A 4-layer stack round a 180° fold. 4 layers of 260 µm cloth taken round a 180 degree fold, drawn as concentric arcs at their own separation. The outer layer runs round a larger radius than the inner one, so it must be longer — by the angle times the separation, which is 2.45 mm here and 0.82 mm at every interface. In a loose stack that length is found by the layers sliding over one another at the fold. In a stitched seam they cannot: the stitches pin them every 3 mm, so the slip a fold needs is 82 per cent of the distance between two stitches and has nowhere to come from. What the arcs cannot show is what happens instead, which is that the fold opens out to a radius the stack can manage.

A crease cannot cross a seam

The outer layer of a folded stack has further to go than the inner, by the fold's angle times the stack's own thickness. A four-layer seam of quarter-millimetre cloth taken through a half turn needs its outer layer to be 2.45 millimetres longer than its inner — and a stitch line every three millimetres has pinned them. So the fold opens out where it crosses the seam, which is what a trouser crease visibly does, and the arithmetic gives the radius it opens to.

finishing · Crease A crease along a 3/1 twill's floats and one across them, worn alike. A strip of 3/1 twill of ring-dyed 50 tex warp and undyed weft folded round a 2 mm radius, the ridge drawn across the page as a dashed line, worn by a flat abrader 50 µm into the ridge: above, with the ridge running along the warp and its floats; below, running across them. Dyed warp dark, bared core red, weft pale. crease along the warp: 83% of the crease's length white, in runs 1.72 mm long on average, the longest 2.08 mm; crease across the warp: 31% of the crease's length white, in runs 0.15 mm long on average, the longest 0.17 mm. On a twill the white along the warp lies in lines as long as a float's crown, across it in dashes one end wide; on a plain weave, with no floats, both are short. What the drawing cannot show is the fibre a real crease tears loose, which blurs every edge here.

A crease across a twill fades in dashes

A garment is not worn flat. It is worn along its folds, where the ridge of a crease stands out and is rubbed first, so the fade follows the crease. On a ring-dyed 3/1 twill a crease running along the warp bares the cores of the floats that lie under its ridge, float by float, and reads as a white line broken only where each float dives: at fifty micrometres of wear, 83 per cent of its length is white, in runs of 1.7 millimetres. The same crease across the warp meets every float at one point and reads as a row of dots, 31 per cent white in dashes of 0.15 millimetres, one end wide. It bares much the same core. A plain weave's creases are dashes whichever way they run.

finishing · Dyeing One crease at four angles to a 3/1 twill's warp, worn alike. Four strips of 3/1 twill of ring-dyed 50 tex warp and undyed weft, each folded round a 2 mm radius with the ridge drawn across the page, worn 50 µm into the ridge by a flat abrader, 24 mm of crease each. Dyed warp dark, bared core red, weft pale. along the warp (0° from the warp): 80% of the crease white, its longest white run 2.0 mm; along the twill's line (33.7° from the warp): 100% of the crease white, its longest white run 45.0 mm; two degrees off the line (35.7° from the warp): 79% of the crease white, its longest white run 15.7 mm; along the other diagonal (-33.7° from the warp): 66% of the crease white, its longest white run 1.0 mm. Along the twill's line the white never breaks, because the crease meets the crown of every end's float in turn; two degrees off, it runs as long strokes that drift off the line of crowns and come back. What the drawing cannot show is the fibre a real crease tears loose.

A crease along the twill fades as one line

A crease along the warp of a ring-dyed 3/1 twill fades as broken lines a float long, and across it as dashes one end wide. Turn the crease to the twill's own diagonal and it fades as a single white line with no break in it at all: the fold meets the crown of one end's float, then the next end's one pick along, then the next, and every crown it meets is at the same place in its float. It is the one direction in which the weave and the crease line up — and two degrees off it the line breaks into strokes whose length is a vernier's.

finishing · Dyeing

Named alongside it

The objects these essays reach for when they reach for this one.

AbrasionCrown lineDenimFloatFold radiusBending bracketBreaking extensionCloth thicknessElastic recoveryFibre finenessRing dyeingSeam

All concepts