Why velvet has a nap direction, how to find it, and why two panels can look like two colours

Run your hand down a velvet sleeve one way and the fabric looks dark and deep. Run it the other way and the same sleeve looks paler and shinier. Nothing has changed except which end of thousands of fibres you are looking at. That direction is called the nap, and it explains a long list of things that otherwise look like faults: why a bodice and a skirt can read as two shades, why a hem redone by a tailor comes out wrong, and why brushing velvet in whichever direction feels natural leaves patches.

What you are actually seeing

Velvet's surface is a dense forest of short cut fibres standing up off a woven backing. Those fibres do not stand perfectly vertical. They lean, slightly and consistently, in one direction, which is set when the fabric is finished.

Look along the lean and you see the sides of the fibres, which reflect light forwards. The fabric reads light and lustrous. Look into the lean and you see the cut ends and the shadows between them. The fabric reads dark and saturated.

The effect is a property of the surface geometry rather than of the dye, so it holds for every pile fabric: velvet, velveteen, velour and corduroy all do it. The longer and denser the pile, the more dramatic the difference. On a deep pile velvet the two directions can look like two different colours entirely.

Finding the direction in ten seconds

Stroke the fabric flat with your palm. One direction feels smooth and leaves the surface settled. The other feels slightly resistant and lifts the fibres. The smooth direction is with the nap, which is the direction the pile leans.

In garment terms, run your hand from shoulder to hem. If it runs smooth going down, the pile is lying downwards and the garment will read lighter and shinier. If it feels resistant going down, the pile points upwards and the garment will read darker and richer.

Pile up is the more common choice in clothing, because depth of colour is usually what velvet is being bought for. Pile down is used deliberately when a shimmer is wanted and in upholstery, where the pile is set to lie down so that it wears and cleans more evenly.

Check the whole garment rather than one panel. On a well made piece every panel runs the same way. On a badly cut one, it does not, and you are about to see why that matters.

Why a bodice and a skirt can look like two colours

A pattern cut from a napped fabric has to have every piece laid out in the same direction, which uses more fabric than laying pieces head to tail. Cutting them nested uses less cloth and produces a garment whose panels shade differently.

On a dress where the bodice runs one way and the skirt the other, the two halves look like two shades of black under the same light. Nothing has faded, nothing is dirty, and no amount of washing or steaming will bring them together, because the fibres are leaning in opposite directions by design.

So this is the one case where shading is a genuine fault rather than physics. The way to tell them apart is to turn the garment round, or take it to a different light: if the two panels swap which of them looks darker as you turn, the nap is running in opposite directions. If one panel stays darker from every angle, you have an actual colour or dye difference.

You can see the same effect harmlessly on a single panel. Sleeves on a one way cut garment are often set so the pile runs round the arm rather than down it, so a sleeve legitimately looks different from the body while both are cut correctly.

What it does to product photographs

A photograph lights the garment from one or two directions, so the nap decides what colour the fabric appears to be in that image. The same dress shot from the front and from the back can look like two products.

This is one of the reasons black velvet is so unreliable in photographs, along with the way its pile hands back the colour of whatever light is in the room. Judge a velvet colour from several images, preferably ones with the fabric at different angles, and give more weight to the shadowed parts than the lit ones.

If an image shows one part of a garment reading noticeably paler, consider nap before you conclude that the item is two tone. If it shows the whole garment reading paler in one photograph and darker in another, that is almost certainly just the light.

Brushing, steaming and recovering a crushed patch

Always brush in one direction, with the nap, using a soft bristle clothes brush. Brushing back and forth stands some fibres up and lays others down, and the result is a patchy surface that then has to be re-settled all over again.

Recovering a crushed patch is a two step job: steam it to relax the fibres, then brush it in the nap direction while it is still slightly warm and damp, then let it dry hanging. Brushing dry velvet does very little, because there is nothing softening the base of the fibre where the bend is.

If a crushed area is standing the wrong way after you have finished, brush it against the nap first to lift the fibres, then with the nap to settle them. Doing it in that order is the difference between a recovered patch and a visible scar. The pressure marks that need this most are at the shoulder, where a bag strap sits, which is why a dress with a built up sleeve head is worth carrying a bag in your hand for.

Alterations, repairs and telling a tailor

Say the word napped when you hand velvet to an alterations shop. A tailor who is not told will cut a replacement piece, a facing or a new hem in whatever orientation is convenient, and the repaired area will shade differently from everything around it forever.

The same applies to taking in a seam on a garment that was cut correctly: as long as the panels stay in their original orientation, nothing changes. Turning a hem is the risky operation, because the folded part now has its pile running opposite to the part above it and can show as a band at the edge.

A velvet garment with a second fabric in it is easier here, because the join does the work of hiding the transition. On a piece that is velvet to the knee and lace below it the hem is not velvet at all, so a length alteration leaves the pile untouched.

For storage, hang velvet rather than folding it, and hang the same garment the same way each time so you are not creating new pressure lines in new places. A fold holds the pile bent at a line, and a line held long enough stops coming back.

Questions people actually ask

What is the nap on velvet?

The direction the pile fibres lean. Looking along the lean shows the sides of the fibres, so the fabric reads light and lustrous. Looking into it shows the cut ends and the shadows between them, so the same fabric reads dark and saturated.

How do you tell which way the nap runs?

Stroke the fabric with your palm. The direction that feels smooth and leaves the surface settled is with the nap. The direction that feels slightly resistant and lifts the fibres is against it. Do it on several panels, because they should all run the same way.

Why does my velvet dress look like two different shades?

Usually because the panels were cut with the nap running in opposite directions, which saves fabric. Turn the garment and watch: if the panels swap which one looks darker, it is nap. If one stays darker from every angle, it is a genuine colour difference.

Which way should you brush velvet?

In one direction, with the nap, using a soft bristle brush. Steam first, then brush while the fabric is still slightly warm and damp, then dry it hanging. For a stubborn crushed patch, lift the fibres against the nap first and then settle them with it.