Textile Structure
how cloth is put together
Concept

Dye affinity — where it appears

How strongly a fibre takes a dye out of the bath: the ratio of the dye held in a unit of fibre to the dye in the liquor beside it at equilibrium. A high affinity slows the dye's advance into a yarn, so it decides how deep a short dip reaches.

Named by 2 essays across one field — each of them below, with the objects they name alongside it.

One dip, two yarns: the same depth of dye. The cross-section of two cotton yarns drawn to one scale after a 20-second dip in a bath whose dye the fibres take up 10 times as strongly as the liquor holds it, each fibre shaded by the dye that reached its distance from the surface. 20 tex: 118 fibres, 167.1 µm across, dyed to 19.7 µm — 24% of its radius and 42% of its section; 74 tex: 435 fibres, 321.4 µm across, dyed to 18.2 µm — 11% of its radius and 21% of its section. The depth in micrometres is the same for both because a dip dyes a depth; the share is not, because the coarse yarn has more section behind the same ring. The fibres are drawn on a lattice and the count is computed; the affinity is an assumed value and every depth moves with its square root.

A dip dyes a depth, not a share

A yarn dyed after spinning is a cylinder the dye has to diffuse into through the liquor between its fibres, and the fibres slow it by taking dye out of the liquor as it passes. A twenty-second dip therefore dyes to a depth, some tens of micrometres, and that depth is almost the same in a fine yarn and a coarse one. So the same dip that colours two fifths of a shirting yarn's section colours a fifth of a denim warp's; eight dips deepen the shade eightfold and leave the ring where it was; and a tighter yarn rings more thinly, because packing closes the pores faster than it narrows the yarn.

finishing · Dyeing A ring-dyed yarn worn flat, step by step. One cotton yarn dyed in a ring 20% of its radius deep, cut flat from the top by an abrader to five depths: worn to 10% of the radius, 1.9% of the yarn has gone and 0% of its width is white; worn to 20% of the radius, 5.2% of the yarn has gone and 0% of its width is white; worn to 30% of the radius, 9.4% of the yarn has gone and 39% of its width is white; worn to 45% of the radius, 16.8% of the yarn has gone and 58% of its width is white; worn to 70% of the radius, 31.2% of the yarn has gone and 74% of its width is white. The olive line is the cut face and the red bar above it is the part of the face that has reached the undyed core. Nothing is white until the cut passes the ring, and then the white arrives quickly. The section is a circle and the ring's edge is drawn sharp; a real yarn is neither, and its fibres migrate, so the core's edge is ragged.

A ring-dyed yarn whitens all at once

Rub a yarn that is dyed in a ring, and for a while nothing shows. The abrader takes off blue fibre, the cut face is blue, and the yarn looks as it did. Then the cut reaches the undyed core, and the white arrives with a vertical tangent, as the square root of the wear past the ring: one per cent of the radius more and an eighth of the width is white. A ring a fifth of the radius deep hides the first five per cent of the yarn's loss and shows half its width white by thirteen. A yarn dyed through never shows white at all. Denim's high-contrast fading is that threshold, drawn over a cloth.

finishing · Dyeing

Named alongside it

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

Ring dyeingYarn diameterAbrasionDenimDiffusionFibre migrationPacking factorYarn count

All concepts