Fabric
Pile fabrics have a direction and it is not a detail
Velvet, corduroy, moleskin and fleece all carry fibres standing away from the base cloth, which changes how they look, how they are cut and how they wear.
A third layer standing off the surface
Most cloth is two-dimensional in the sense that matters: yarns interlacing in a plane. A pile fabric adds a third element, a set of fibres or loops that stand up from the base structure, giving the cloth a depth you can push your finger into.
The pile can be made several ways. It can be woven as extra loops that are then cut, as in velvet and velveteen. It can be woven as floats that are slit into rows, which is how corduroy gets its ridges. It can be raised from the ground cloth itself by brushing, which is how flannel and moleskin acquire their surface. Or it can be knitted and brushed, as fleece is.
What they share is that the surface you touch is not the structure that holds the garment together. That separation explains nearly everything that follows.
Direction changes the colour
Cut pile lies at an angle rather than standing perfectly upright, and light striking it behaves differently depending on which way you look along the fibres. Stroke velvet one way and it looks dark and rich; stroke it the other and it looks pale and silvery. Nothing about the dye has changed.
This is why pile fabrics have to be cut with every pattern piece facing the same direction. Reverse one panel and it will be a visibly different shade from its neighbours under any light, and no amount of pressing corrects it. Laying out a pattern this way uses noticeably more cloth, which is part of why pile garments cost more.
It also settles a long-running argument about which way the pile should run on a finished garment. Both conventions exist, one favouring the deeper colour and one favouring resistance to the pile being rubbed the wrong way in wear. Neither is wrong; consistency within the garment is what actually matters.
Pressure marks and why pile fabrics need care
Because the pile stands away from the base, it can be crushed. Sit for an hour in velvet and the fibres in contact with the chair are bent flat, and they reflect light differently from the ones around them, so the mark is clearly visible even after you stand up.
Most crush marks are temporary if the fibre has enough resilience. Steam is the standard remedy, held above the fabric rather than pressed onto it, because the moisture relaxes the bent fibres and allows them to stand again. What must not happen is an iron laid directly on the surface, which crushes the pile permanently and leaves a shiny flattened patch.
Hanging is preferable to folding for the same reason. A fold in a pile fabric compresses the pile along a line, and that line survives a long time.
Wear appears where the pile is lost, not where the cloth thins
A pile fabric shows its age differently from a flat one. The base cloth is usually sound long after the garment looks worn, because what has actually happened is that pile has been abraded away at the points of highest friction: elbows, seat, the inside of the thighs, the front of a cuff.
On corduroy this is unmistakable, since the ridges wear flat in stripes and the flattened areas read as pale bands. On moleskin and brushed cottons the raised surface simply disappears and the cloth underneath shows through as a smoother, shinier patch.
There is no practical repair for lost pile. It can be disguised slightly by brushing surrounding fibres over the bare area, and that is about the limit. This is one reason pile garments in hard-wearing use tend to be cut from heavier, denser constructions with more fibre to lose.
The insulation argument, and its cost
Pile fabrics are warm out of proportion to their weight, and for the same reason woollen cloths are. Still air is a poor conductor of heat, and a forest of upright fibres holds a great deal of still air against the body while weighing very little.
Fleece is the clearest example, being a knitted synthetic brushed on one or both faces so the surface becomes a thick layer of trapped air. It dries fast because the fibres themselves absorb almost nothing, and it is warm because of geometry rather than chemistry.
The cost is wind. A pile surface has no wind resistance to speak of, so moving air strips the trapped layer away and the insulation collapses. That is precisely why fleece is worn under a shell and rarely as an outer layer in weather, and why brushed cottons feel warm indoors and disappointing on an exposed street.
Common questions
Can crushed velvet be restored?
Often, if the crushing is recent and the fibre is resilient. Hold a steamer above the fabric without touching it and brush the pile gently upright as the moisture relaxes it. Old marks that have been repeatedly compressed in the same place, especially on the seat of a garment, usually will not fully recover.
Why does corduroy wear out at the knees so visibly?
Because the wear removes pile rather than cloth. The ridges flatten under repeated pressure and abrasion, so the area reflects light differently and reads as a pale, shiny patch long before the base fabric is anywhere near failing. The garment is stronger than it looks at that point.
Does pile direction affect how a garment should be stored?
Hanging is better than folding, since a fold compresses the pile along a line that can become permanent. Avoid heavy garments pressed hard against pile in a full wardrobe, and give velvet and corduroy a little space. The pile needs room to stand up.
Amrita has been reporting on fit, fabric, care & repair since long before it was fashionable and reads the small print so you do not have to.