Dye Lots: Why Your Reorder Does Not Match, and What to Do About It

A dye lot is a single batch of fabric dyed together, normally measured in hundreds of kilos. Within one lot the colour is consistent because the whole quantity sat in the same vessel, in the same dye liquor, at the same temperature, for the same time. A second lot run days or months later involves a different vessel of water, a slightly different batch of dyestuff, a marginally different fabric substrate and fresh conditions. A good dye house controls all of that tightly and the result is close, but identical is a different claim and it is not one anyone in the industry can honestly make across separate lots. Keep the approved lab dip and a bulk swatch on file, dated and labelled, because without a physical standard a later disagreement has nothing to point at.

Because it came from a different dye lot, and that is normal rather than a fault. Fabric is dyed in batches, not continuously, so a repeat order almost always means a new batch dyed at a different time under marginally different conditions. Factories reduce the difference by dyeing bulk against an approved lab dip and checking the result back against that standard, but they cannot eliminate it. If an exact match across seasons genuinely matters to your product, the fix is not a tighter promise from your supplier, it is buying the fabric for both runs in a single lot up front and holding the cloth. Deep blacks, strong reds and fluorescents are harder to hold consistently than mid-tone heather greys and naturals, so a brand built on a difficult shade should plan for more effort.

No, and any supplier who promises it is either misunderstanding the question or answering it carelessly. We cannot promise that a lot dyed next spring will be indistinguishable from one dyed this autumn, because each lot is a fresh vessel of water, a different dyestuff batch and a marginally different fabric substrate. What we do promise is narrower and checkable. Bulk is dyed at our partner mill to the lab dip you approved, and we check the bulk back against it, bundle by roll during cutting so no single garment is assembled from two shades, and keep your approved standard on file for the reorder. If a lot comes out at the edge of the agreed tolerance, we tell you before it ships, not after it arrives. Where exact consistency across seasons is essential to the product, the answer is to buy the fabric in one lot, and we will plan the order that way with you.

Because every colour is its own dye lot, and one dye lot cannot be shared between colours. Fabric is dyed in batches measured in hundreds of kilos, so a style offered in black, navy and grey needs three separate batches of cloth, each dyed to its own approved lab dip and each with its own set of trims. That is three runs of fabric, not one order divided three ways, which is why our minimum is 150 pieces per style and per colour rather than per style alone. It also means spreading a small first order across several colourways is the most expensive thing a new brand can do. The same money spent on one colour deep buys a better unit price and a simpler reorder than the same money spread across several shallow colourways. Our MOQ calculator shows what a colour split does to your total piece count.

A lab dip is a small swatch of your fabric dyed to your colour reference, produced before any bulk cloth is committed. You approve it, reject it, or ask for it to be redone warmer, cooler, lighter or deeper, and bulk is then dyed to whichever version you approved. Two rules make the process work. Give a physical reference such as a Pantone TCX textile colour or a swatch you already like, rather than a colour from a screen, because light and pigment do not correspond. And assess it under consistent lighting, since two colours can match under one light source and differ under another. A light box is the standard tool; if you do not have one, compare the dip and your reference in the same daylight each time, never in mixed light, and keep the approved dip filed and dated so the bulk can be checked back against it.

Metamerism is when two colours look identical under one light source and different under another. It is a real phenomenon, and it explains why a lab dip and your reference can agree in one room and disagree in the next. For a clothing brand it matters most at approval. Compare the lab dip with a physical reference rather than a screen colour, and compare the two under the same light each time, a light box if you have one. Dye houses and retailers assess colour in standardised light boxes for exactly this reason. The same discipline carries through to production. Bulk fabric is dyed to the lab dip you approved and then checked back against it, and any visual comparison between the two should be made under the same controlled light. Keep the approved lab dip filed, dated and labelled, so every later comparison is made against the same physical standard rather than a memory of the colour.

What is normal is an agreed commercial tolerance rather than an exact match: buyer and supplier agree a limit, and lots falling inside it are accepted. Colour is not judged by eye alone in a professional chain. It is measured, usually with a spectrophotometer, expressed as a numeric difference from the approved standard, and assessed visually against a grey scale. The important thing for a brand to understand is that a tolerance exists at all: your order is for a colour within an agreed distance of an approved standard, not for an exact colour. If exactness across time is essential to your product, say so before the first order rather than after the second, because the solution is a different buying strategy rather than a tighter promise from the factory. If one of your lots comes out at the edge of the agreed tolerance, we tell you before it ships, not after it arrives.

By bundling, and it is standard practice on a well-run floor. Even inside a single dye lot there can be very slight variation between rolls, so after cutting, the pieces are kept together in bundles by roll and shade so that a single garment is never assembled from two different rolls. That is why a difference between two seasons sitting on a shelf is invisible while a difference between a sleeve and a body would be glaring. If you are ever shown a garment with mismatched panels, the problem is bundling discipline in the cutting room rather than the dye house. It is also why we will tell you before shipping if a lot has landed at the edge of tolerance, rather than letting you discover it when the cartons open.