Garment dyeing and washing in Bangladesh

Because the colour is applied to finished garments in batches, and every batch is a slightly different combination of dye liquor, temperature, time and load. That variation is part of the look: it is what gives garment-dyed product its depth compared with flat piece-dyed fabric. The way it is managed is by control rather than elimination. That means a sealed shade standard you approve, every batch compared against it under standard lighting, and garments sorted into shade bands so that pieces packed together match. Ask for the band reference on the carton, which matters for reorders and replacements. If your programme cannot tolerate visible variation, for example a corporate uniform where garments are bought individually over years, garment dyeing is the wrong process and we will recommend piece-dyed fabric instead. We say so at the costing stage, not after a dye trial.

It depends on the fibre, the fabric structure and the process, so the honest answer is that it is measured rather than estimated. Cotton-rich fleece shrinks more than a cotton-polyester blend; a heavily enzyme-washed garment moves more than a rinse wash; and length and width shrink at different rates. Before cutting, the actual fabric and rib are wash-tested in the actual process, the shrinkage is measured, and the pattern is adjusted so the finished garment lands inside your size chart after processing. Then a pre-production sample goes through the whole process and is measured against the chart before bulk cutting is approved, and production garments are measured batch by batch. What you should not accept from any supplier is a size chart quoted before washing with the shrinkage left as your problem.

Both colour the garment after it is sewn, but they colour it differently and age differently. Reactive garment dyeing on cotton bonds the dye to the fibre, giving a full, even colour that penetrates the fabric and holds well in washing; it is the process for solid shades with depth and softness. Pigment dyeing binds coloured pigment to the surface of the fabric with a resin rather than into the fibre, so the colour sits on the outside and rubs and washes away gradually at seams, edges and high points. That is not a fault; it is the point, and it produces the faded, lived-in look of a favourite old sweatshirt from the first wear. Pigment-dyed product needs a care label that says it will fade, and the buyer should approve a washed sample, not an unwashed one. We brief either from a colour standard and seal a processed sample.

Only a test or a certificate can show that, and the way to be sure is to name the list. Most retailers publish a restricted substances list for finished products, and many also require their suppliers’ wet processes to follow the ZDHC Manufacturing Restricted Substances List, which governs the chemicals used in dyeing and washing rather than what remains in the garment. Name the list that applies at the enquiry stage, ask whether the wash plant works to it, and where a test is required, have the garment tested at an accredited laboratory for the parameters your list names and keep the report. What we do not do is claim compliance without a test or a certificate, and we will tell you if a requested effect, such as a heavy bleach or a particular potassium permanganate spray, conflicts with your list or with the plant’s own restrictions and propose the laser or ozone route instead.

Garment dyeing means sewing the garment in undyed fabric and dyeing it as a finished piece, whereas piece dyeing colours the fabric in rolls before it is cut and sewn. Garment dyeing gives a distinctive depth of colour and a soft, lived-in hand-feel, and it lets a brand hold undyed stock and colour it closer to the season. The cost is control: the whole garment, including ribs, threads and labels, takes the dye, and each component can take it differently; shrinkage happens after sewing, so the pattern must be compensated; and batches vary, so garments are sorted and packed by shade band. Piece dyeing gives a flatter, more consistent shade across a fabric lot, with shrinkage controlled before cutting, which is why it suits programmes that must match over years, such as corporate uniforms; trims are then matched to the fabric by lab dip. We recommend one or the other at costing, before any dye trial.

An enzyme wash uses cellulase enzymes to remove surface fibre from cotton, giving a softer hand and a mild, even fade, while a stone wash tumbles garments with pumice or synthetic stones that abrade the surface for a more worn look. The difference is how the effect is reached. Enzymes work chemically and evenly, so they soften without the mechanical abrasion of stones, which suits knits and denim that should feel soft and look lived-in rather than distressed. Stones rub hardest where the garment is raised, so seams, pocket edges and hems fade first, which is the character buyers want in vintage denim; the cost is more strain on the fabric and the trims. Most plants now combine the two, using enzymes to reduce the damage stones cause. Both shrink the garment, so the fabric is wash-tested in the actual recipe and the pattern compensated. Brief either wash from a reference garment and approve it on a physical standard.

An acid wash is a patchy, high-contrast bleached finish, and despite the name it is bleach, not acid, that does the fading. In the method patented for the look, US patent 4,740,213, granted in 1988, pumice granules are soaked in a bleaching agent such as hypochlorite and tumbled with the garments in a dry drum, so colour is stripped wherever a granule touches, and the leftover bleach is neutralised by washing afterwards. A stone wash, by contrast, tumbles garments with stones in water, which abrades the surface and fades it gradually, most at seams and edges. Acid wash is the harder of the two on fabric strength, and its chemistry must fit your retailer’s restricted substances list. Neither wash can be briefed in words alone: send a reference garment, say how much variation you accept, and approve a washed standard on your bulk fabric.

A bio wash and an enzyme wash use the same kind of enzyme for different aims, and a silicone wash is a softener finish with no enzyme in it. Bio wash, or bio-polishing, is the name knitwear suppliers give to a cellulase treatment that cleans the fabric surface: Novonesis, an enzyme maker, says its biopolishing cellulases remove the protruding microfibrils that cause fuzz and pilling, and that mills apply them before, during or after dyeing (product page read on 1 October 2026). Enzyme wash usually means cellulase used on finished garments, especially denim, to soften and fade them. A silicone wash adds a silicone softener in the last bath for a smooth, slippery hand; it changes the feel, not the surface. Quotes often list them together, as in bio wash plus silicone wash. Ask which of them your price includes, and have pilling checked to ISO 12945-2:2020, the modified Martindale method, on the finished fabric.