Ticking Stripe
Ticking is a densely woven cotton or linen cloth developed to contain the feathers and horsehair of mattresses and bolsters. The weave is tight enough that a quill will not work its way through, and the characteristic narrow stripe was originally a weaving convention rather than a decorative one: the coloured warp threads made it easy to judge the cut and the grain of a utility cloth.
The stripe is almost always in one colour on an undyed ground, and the classic colours are the ones that were cheap and fast: indigo blue, madder red, and a black that usually reads as charcoal. Widths vary from a hairline to something close to a centimetre, often in irregular groups rather than an even repeat.
In a room ticking behaves like a texture rather than a pattern. Because the stripe is fine and the colour count is low, it can be used at large scale, on curtains or loose covers, without dominating anything. It is one of the few patterns that will sit beside a strong print without competing, which is why it turns up so often as the lining or the secondary cloth in a scheme.
The direction matters more than it looks as though it should. Run vertically on a curtain the stripe disappears into the folds; run horizontally on a seat or a bolster it emphasises the shape of the piece, sometimes more than the piece can carry.