What is nap? Why velvet looks darker one way

Nap and pile: two words, one problem

Strictly, the two words describe different things. Pile is made of extra yarns woven or knitted into the cloth so they stand up from the base: velvet, velveteen, corduroy and towelling are pile fabrics. Nap is created after weaving, by brushing or raising the surface so loose fibre ends lift and lie flat in one direction, as on flannel. In everyday sewing language both are called nap, and dressmaking patterns use the phrase “with nap” for any fabric that must be cut with all its pieces facing the same way.

The practical test is the same for both. Hold the fabric up, look along it from the top and then from the bottom, and if it changes colour or sheen, it has a direction.

Why velvet looks darker one way

When the pile points up towards your eye, you look into the ends of the fibres and the tiny shadows between them, so the colour reads deep and rich. When it points down, you see the sides of the fibres, which are smoother and bounce more light back, so the same velvet looks paler and shinier.

Neither direction is wrong. Many dressmakers cut velvet with the pile running up for the deeper colour, while others prefer it running down because it feels smoother to the hand and sheds dust more easily. What matters is that every piece of one garment, and ideally anything worn with it, runs the same way. Our velvet guide covers pressing and care, and the article on types of velvet explains how silk, viscose and micro velvet differ. To find the direction yourself:

• Stroke it: run your palm along the length, parallel to the selvedge. Smooth means you are going with the pile; resistance means against it.
• Look from both ends: lay the cloth flat in daylight and view it from each end. The darker, richer view is pile up.
• Mark it: a chalk arrow or a safety pin on the back of each piece saves confusion once the cloth is folded.

Other fabrics with a direction

Velvet is the obvious example, but plenty of other cloths shade or change with direction. Some have a nap in the strict sense; others have a sheen or a pattern that only reads one way.

• Corduroy and velveteen, which have a short cotton pile.
• Brushed cotton and flannel, where brushing lays the surface fibres down one way; see our article on brushed cotton.
• Faux suede and peach-finish fabrics, with a very short raised surface.
• Satin and some shiny silks, where the sheen can look different from each end even without a pile.
• Shot or two-tone fabrics, whose colour shifts with the angle of the light.
• One-way prints, such as flowers that all grow upwards, and borders that run along one edge.

What nap means when you order

Cutting every piece in one direction stops the pattern pieces from interlocking top to tail on the cloth, so a fabric with nap can need noticeably more length than a plain cotton for the same design. Wide trousers, long sleeves and a full kameez make the difference bigger. Our guide to fabric widths explains why the width of the cloth changes the amount too.

If you are sending your own velvet for Stitching Only, photograph both sides in daylight, include the label and say whether you prefer the pile up or down. We confirm the fabric is suitable and that there is enough for a one-way layout before you post anything. You can begin on the stitching quote form.