Garment Dyeing vs Piece Dyeing, and How Acid Wash and Washed Looks Are Made in Bulk

Piece dyeing colours the knitted fabric before it is cut, so every panel comes from one even, controlled batch. Garment dyeing colours the finished, sewn garment, so the thread, labels and seams go into the bath too, the piece shrinks in the process, and the result is softer and slightly uneven by design. Pigment dyeing fixes colour to the surface with a binder instead of bonding it, so it fades into a worn look. Acid, mineral, stone and enzyme washes are treatments applied to garments after they are coloured, to strip, mottle, soften or age the surface. The trade-off is always the same: the later the colour or the wash goes in, the more character you get, and the less exactly one piece, or one reorder, matches the next.

This guide is for founders who have seen an acid wash hoodie selling and want to make one. One fact first: we cut and sew on our own floor in Narayanganj, and the dyeing on our orders is done at partner dye houses we book and inspect. Our custom dyeing page sets out who answers for what.

When the colour goes in, and how it holds on

Most confusion here comes from mixing up separate questions. The first is when the colour is added: to the yarn before knitting (yarn dyeing, which is how knitted stripes are made), to the knitted fabric before cutting (piece dyeing), or to the sewn garment (garment dyeing). The second is how the colour holds on: reactive dye bonds chemically with cotton, while pigment sits on the surface, held there by a binder. Washes are a third layer: they take colour away or change the surface of a garment already coloured.

So "garment dyed" and "reactive dyed" are not alternatives: a garment-dyed hoodie is often dyed with reactive dye, just later. "Pigment dyed" describes the chemistry, and the faded look most brands mean by it is made on the garment.

Piece dyeing: the default, and the most consistent

Piece dyeing means the knitted fabric is dyed in rolls before anything is cut. The EU's reference document on best available techniques for the textiles industry notes that batch processes are the most common route for knitted fabric, and that reactive dyes make up about a third of the dyes used on cellulose fibres such as cotton. After dyeing, the fabric is dried, compacted and set to width, which is where most of its shrinkage is taken out before it reaches a cutting table.

Because the whole lot sat in one machine, colour within it is even. Between lots it sits within a tolerance rather than matching exactly, which is the subject of our guide to dye lots and why reorders drift. For a core colour you will reorder, or a set where the hoodie must match the jogger, piece dyeing is the right answer almost every time.

Reactive dye: why it lasts, and what it leaves in the water

Reactive dye bonds chemically with the cellulose in cotton, which is why it washes well and why we specify it by default. The cost is in the water. The same EU reference document describes batch reactive dyeing as adding dye, an alkali and salt to the bath, with more salt needed for deep shades: a deep shade can take several times the salt of a pale one. Not all the dye fixes to the fibre. The unfixed share is washed off afterwards and leaves with the salt in the effluent. That is why effluent treatment is the first thing to ask a dye house about.

Garment dyeing: colour after sewing

In garment dyeing, the hoodie or tee is cut and sewn from undyed fabric, usually prepared-for-dye (PFD) cloth that has been scoured and bleached so it takes colour evenly, and the finished pieces go into a garment-dyeing machine. Everything sewn into the garment goes through the bath: body, rib, thread, labels and drawcord.

The appeal is the look. Seams, hems and folded edges take colour slightly differently from flat panels, which gives the garment tonal depth, and the tumbling in the machine leaves it softer than a piece-dyed equivalent. Rib and body are coloured together, which removes the risk our rib guide warns about, a cuff dyed in a different lot from the sleeve, although a rib with a different fibre content can still take the colour differently.

The problems are practical. The garment shrinks in the hot bath, so the pattern has to be cut larger to land on your finished measurements. Polyester sewing thread and most polyester labels do not take the dyes used on cotton, so they stay their original colour unless you choose cotton thread or decide the contrast is the look. A print applied before dyeing has to survive the bath and shrink with the fabric, so decoration is usually planned for after it. And each machine load is its own small lot, so pieces vary a little within a batch and more between batches.

Pigment dyeing: the faded look, by design

The EU reference document defines pigment dyeing as depositing an insoluble pigment, which has no affinity for the fibre, onto the textile and fixing it there with a binder. Because the colour sits on the surface rather than bonding with the cotton, it wears away at the seams and high points with every wash and every rub. That is why streetwear brands specify it: a pigment-dyed sweatshirt looks lived-in from the first day.

Rubbing fastness (crocking) is weaker, so a dark pigment-dyed piece can mark a light bag or sofa; ask for a rubbing test to ISO 105-X12 on the dyed sample. And the care label should tell customers to wash it with like colours, which our care label guide covers. If you want a colour that stays put, pigment is the wrong choice. It is a style decision, not a quality one.

How acid wash is actually done

Acid wash is mostly not acid. The name comes from denim, where pumice stones are soaked in a strong oxidising solution and then tumbled with the garments. A 2020 study in the Journal of Textile and Apparel, Technology and Management describes the denim version as pumice soaked in potassium permanganate with a small amount of phosphoric acid, run with the garments, then neutralised and rinsed; the same paper compares it with a bleach wash using hypochlorite. Wherever a stone touches, colour is stripped from the surface; where it does not, colour stays. The result is the high-contrast, marbled or speckled look people search for as an acid wash hoodie.

On a cotton knit hoodie the principle is the same, with three differences. The base is usually a dark colour, because contrast needs depth to strip from. Fleece and French terry are thicker and loopier than denim, so the effect comes out softer and blotchier. And oxidisers attack cotton as well as colour, so a heavy wash can weaken the fabric and the seams: wash-test the sample and pull at the seams before you approve it. No two pieces match, so you are approving a range of variation, not a copy.

Mineral, stone and enzyme washes

Mineral wash is a trade name rather than a defined process, and suppliers use it for slightly different things. Most mean a gentler, cloudier version of the acid effect: a garment-dyed piece treated so the colour breaks up into soft mottling rather than sharp contrast. Because the term has no fixed meaning, never order a mineral wash by name alone. Send a reference garment or clear photos, and approve the wash on your own sample.

Stone wash means tumbling garments with pumice stones in an industrial washer, so that abrasion fades the surface and breaks in the handle. On knits it needs care: the loops in fleece and terry can snag or fuzz, and light jersey can hole. It suits heavy fabric better than light.

Enzyme wash, also called bio-polishing or bio-washing, uses cellulase enzymes, which act on the cellulose in cotton. The EU reference document describes cellulases removing loose fibres from cotton yarn or knitted fabric, giving a soft feel and reducing pilling, and it notes the trade-off: bio-polishing may reduce fabric strength and weight. It is the least visible wash and often the most useful, because a hoodie that pills early is a returns problem.

Tie-dye and dip-dye

Tie-dye resists the dye by folding, twisting or binding the garment before it goes into the colour, so the bound areas stay lighter and form spirals, crumples or bands. Dip-dye immerses only part of the garment, or lowers it in stages, to give a fade or a stepped band from hem to chest. Both are hand processes applied garment by garment, so their cost is labour per piece and it does not fall much with volume. Both vary from piece to piece, and the approved sample sets the range you sign off. If every unit must match, choose a different method.

Shrinkage: why the pattern has to know the process

Cotton knits are knitted under tension and relax when they are washed. On a piece-dyed order the fabric is compacted after dyeing, so most of that movement has happened before cutting, and the pattern is cut close to finished size. On a garment-dyed or washed order, the hot bath and the tumbling come after sewing, so the garment shrinks as a garment. The pattern has to be cut larger, by an allowance measured on your fabric rather than guessed, so the finished piece lands on your size chart.

The allowance is rarely the same in length and width, and it differs by fabric. The reliable way to set it is to put a test garment through the actual process, measure it against the pattern and adjust. A recognised method for measuring dimensional change after washing is ISO 5077. Our guide to pre-production samples shows how to turn a wash test into numbers, and the washed sample, not the unwashed one, is the size your customer receives.

Colour on a reorder

Every method sits somewhere on a line from repeatable to unique. Piece-dyed reactive colour is the most repeatable: a reorder is dyed to the same approved lab dip and lands within the agreed tolerance. Garment dyeing adds variation inside each batch. Pigment keeps moving after it leaves the factory, because it fades in wear, so a new piece beside a customer's six-month-old one will look different by design. Washes and hand dyes are matched to the same range of variation, using the same approved sample, so keep that sample and a bulk piece from each delivery.

What each method does to your minimum

Our minimum is 150 pieces per style and per colour, whichever method you choose, because each colour is its own dye run. Two things change in practice. First, a wash turns one colour into two products: a black hoodie and an acid-washed black hoodie have separate approved samples, so ask at quote whether the washed version counts as a colourway of its own, because it usually needs its own minimum. Second, tie-dye and acid wash are labour per piece and do not fall much with volume, while dyed fabric gets cheaper per piece as the lot grows. Put your styles and colourways into the MOQ calculator before you plan a range of six washes.

The chemical and environmental side

Dyeing and washing are where chemicals enter a garment's supply chain, so they are where the rules apply. Four are worth knowing by name.

• Effluent treatment. GOTS 7.0 requires wastewater from every wet-processing unit in a certified chain to be treated in an effluent treatment plant before it is discharged. On our orders, dyeing is placed only with partner units that run wastewater treatment.
• The ZDHC MRSL. The Zero Discharge of Hazardous Chemicals group's Manufacturing Restricted Substances List applies to the chemical formulations used in manufacturing rather than to the finished garment: it sets limits for each ingredient and identifies substances barred from intentional use. Version 4.0 is current and adds limits for unintentional PFAS contamination.
• REACH in the EU. Annex XVII entry 43 bans azo dyes that release listed aromatic amines above 30 mg/kg in textiles that touch the skin. Finishes count too: since 10 October 2026, the PFHxA limit applies to clothing in every homogeneous material, which our guide to EU PFAS rules covers.
• GOTS. For a style in organic cotton, made in our GOTS-certified facility (RSC 9687), the dyeing and washing must meet GOTS as well, at partner units that hold their own scope certificates. GOTS 7.0 allows only oxygen-based bleaching inputs, such as peroxides and ozone, which rules out a chlorine bleach wash on certified cotton. It prohibits enzymes derived from genetically modified organisms, azo dyes that release carcinogenic arylamines, and garment finishing methods harmful to workers, naming sandblasting of denim. Our GOTS guide explains the rest.

No dyeing or washing is free of environmental cost, and a wash adds a second wet process to a garment that has usually been dyed once already. If sustainability is part of your story, the gentler route to a lived-in look is often a single garment dye or an enzyme wash, rather than a dye followed by a bleach wash.

What to put on the tech pack

A garment-dyed or washed style needs more on the tech pack than a plain one, because more decisions happen after sewing. Our free hoodie tech pack template has the sections; these are the lines to add.

• The process, in order. For example: PFD fleece, cut and sew, garment dye, acid wash, then print. The order changes the result.
• The shade standard. A Pantone TCX reference or a physical swatch for the base colour, approved as a lab dip on your fabric. For garment dye, approve the colour on a dyed sample garment as well.
• The wash standard. A reference garment or photos, and what counts as too much. The approved sample becomes the range bulk is judged against.
• Finished measurements, after shrinkage. State that the size chart gives measurements after dyeing and washing, and ask for the shrinkage allowance used on the pattern. See how to build a size chart.
• Thread, labels and trims. Cotton thread to take the dye, or polyester for a deliberate contrast; labels that survive the bath; drawcords and eyelets that will not bleed or rust.
• Tests. Wash fastness, for example to ISO 105-C06, rubbing fastness for pigment and dark shades, and a seam check after any bleach or stone wash.
• Care wording. Wash with like colours, and wash inside out, for garment-dyed, pigment-dyed and washed pieces.

Honest trade-offs

• Piece dyeing gives the most even colour and the easiest reorders, and the least character.
• Garment dyeing gives softness and depth, and costs you exact sizing, exact colour and a second handling stage.
• Pigment dyeing gives an instant vintage colour that keeps fading, which is the point until a customer complains that it did.
• Acid and mineral washes give a look people search for by name, at a labour cost per piece, with fabric strength to watch and no two pieces alike.
• Stone and enzyme washes improve the handle; stone is hard on light knits, and enzymes take a little weight and strength from the fabric.
• Tie-dye and dip-dye are the most distinctive and the least repeatable.

If you are launching with one hoodie, the safe first order is a piece-dyed core colour, with a washed version added as a second colourway once the first has sold.

How we handle dyed and washed orders

We specify reactive dye by default, and we offer pigment dye, garment dye, tie-dye and acid wash on garments we cut and sew to your spec, not on stock blanks. The dyeing is done at partner dye houses we book and inspect. You approve a physical lab dip before bulk, it stays on file against your style, finished garments are checked against it under controlled light, and a lot that misses it is re-run at our cost. For a washed or hand-dyed style, we will tell you before you commit if the look cannot be repeated. Mineral, stone and enzyme washes are not among our listed techniques, so ask before you design around one.

Production runs 40–50 days after sample approval, and an order takes about 70 days from order to your door by air. A garment-dyed or washed style adds a wet process after sewing, so we confirm the plan for your style when we quote. Our hoodie manufacturing page covers the garment itself, and the custom dyeing page covers colour matching in detail.