What happens inside a denim washhouse

A jean leaves the sewing line stiff, dark and characterless. Everything you recognise about a pair of jeans — the fade down the thigh, the soft hand, the worn hem, the whiskers at the hip — is put there afterwards, in a washhouse.

BPD is the only full-service commercial denim wet and dry process facility on the East Coast. Here is what actually happens on the floor.

Wet process: everything that happens in a drum

Desize. Raw denim carries a starch from weaving. It comes off first, or nothing else takes evenly.

Stone wash. Pumice tumbles with the garments and abrades the surface. It is the oldest way to take the newness off a jean, and still the most convincing.

Enzyme wash. Cellulase enzymes eat the surface fibres instead of stone. Softer hand, less damage to the garment and the machine, and a cleaner drum at the end of it.

Bleach and tint. Bleach pulls the indigo back. A tint puts a cast over the whole garment: warm, grey, aged, or just knocked back a shade.

Over-dye. A finished garment dropped into colour, so the dye sits over the weave, the seams and the thread — which is why an over-dyed jean never looks like a piece-dyed one.

Dry process: everything that happens standing still

Hand sanding. The garment goes on an inflatable form and sandpaper goes on the places a body would wear it: the front of the thigh, the seat, the knee.

Laser. An image burned into the surface of the cloth. Whiskers, wear, graphics, even a photograph. No water, no stencil, and repeatable to the millimetre.

Spray. Colour or bleach laid on by hand with a gun, where a drum can't put it.

Resin and tacking. Resin cured into the cloth, the garment pinned, so creases hold exactly where they should.

Grinding and destroy. Hems, pockets and seams taken back so they read as years old rather than minutes.

The order is the formula

Almost no finish is one process. A look is usually three or four of them in a particular order, at particular times and temperatures — and that order is the formula. We write ours down and hand them over, so a factory can repeat the look at production scale without re-inventing it.

Want to see it happen? The classes run one day a month and you work on your own garments. Want it done for you? Tell us what you need.