A mill's colour or lab manager, a merchandiser, and a buyer all face the same moment on almost every order: a colour has been approved once, small, and now someone must decide whether it is safe to commit a full, often 300-kilogram or larger dye lot to it. This lesson mainly teaches a decision flow: when is a colour actually ready for bulk dyeing, and when is it not.
Without a clear answer, a mill either wastes time re-approving a colour that was already good, or it commits an entire dye lot to a colour that only looked right in a small sample. A lab dip and a strike-off are the two checkpoints that stand between a colour standard and a full dye lot. Skipping either one, or treating them as the same step, is one of the most common and most costly mistakes in colour approval. This lesson explains what each sample is, why both exist, and what a merchandiser or lab manager does with each one before the full dye lot is allowed to start.
You need: to know what a colour standard is (lesson 3.1 covers this). You do not need to know how a dye machine works or how a dye recipe is written.
By the end of this lesson you can:
Not covered here: how a colour standard itself is set and communicated (lesson 3.1), what a conditional approval means and what happens next (lesson 3.3), and the dye classes used to reach a given colour (Course 2).
| Term | Meaning |
|---|---|
| Colour standard | The reference colour a buyer sets and communicates to a mill, against which every lab dip and bulk dyeing is checked. |
| Lab dip | A small dyed sample, often yarn or a small fabric swatch, a mill produces in its lab to show how close it can get to a colour standard, before committing to a full dye lot. |
| Strike-off | A larger sample, produced on the actual bulk fabric rather than a lab sample, confirming the colour holds on the real production substrate. |
| Dye lot | One batch of fabric dyed together in the same vat, which can differ slightly in shade or hand-feel from another batch of the same colour. |
| Dye-lot minimum | The smallest quantity a mill will run as one dye batch. |
A lab dip is a small dyed sample, often yarn or a small fabric swatch, that a mill produces in its lab to show how close it can get to a colour standard before committing to a full dye lot. A strike-off is a larger sample, produced on the actual bulk fabric rather than a lab sample, confirming the colour holds on the real production substrate. Both exist for the same reason: to catch a colour mismatch before the mill commits time and material to a full dye lot, often 300 kilograms or more at Colorline Dyeing (docs/02 section 6). A lab dip checks the colour recipe quickly and cheaply. A strike-off checks that the recipe still works on the real fabric the bulk order will actually use.
| What can differ | The shapes you meet | Why it matters |
|---|---|---|
| Size | A lab dip is small, often only a few grams of yarn or a swatch the size of a hand. A strike-off is larger, enough fabric to judge the colour across a real production width. | A lab dip is cheap and fast to produce; a strike-off costs more and takes longer, which is exactly why the lab dip is approved first, before the strike-off is made. |
| Substrate | A lab dip is dyed in the mill's lab, sometimes on a small piece of fabric or yarn that was never meant for production. A strike-off is dyed on the actual bulk fabric, the same batch of greige fabric the full order will be cut from. | Fibre preparation and absorbency can differ between a lab sample and the real production substrate, so a lab-dip match does not guarantee a strike-off match. |
| Speed of iteration | A lab dip can be adjusted and re-dyed within a day in most mills, since it uses little material. A strike-off takes longer to prepare and is not repeated as freely. | Early colour negotiation with the buyer happens on lab dips, where mistakes are cheap; a strike-off is for confirmation, not for repeated experimentation. |
| Order shape | The same two-step sequence applies whether the order is export or domestic, and whether the business is Make to Order, Make to Stock or a hybrid; a domestic Make to Stock reorder still needs its own strike-off, even if an earlier order used the same colour standard. | A merchandiser cannot assume that because a colour was approved once, on some earlier order, it is automatically approved again on a new fabric batch. |
| Product family | Knit fabric (as in Order A), woven fabric, and yarn-dyed products such as some socks and hosiery all use the same lab-dip-then-strike-off sequence, though a yarn-dyed product's strike-off is a small dyed hank of yarn rather than a fabric swatch. | The two-step principle holds across product families; only the physical form of the sample changes. |
Cedar & Co., a local brand with 12 shops that stocks its own shelves from its own forecast (Make to Stock, domestic), needs Order A's own fabric colour (single jersey, 180 GSM, Ne 30/1 combed cotton) in a shade it has already set as a colour standard. Rowad Knits knits the greige fabric; Colorline Dyeing dyes and finishes it. Before Colorline Dyeing commits its 300-kilogram dye-lot minimum to this colour, it produces a lab dip against Cedar & Co.'s colour standard, then, once that lab dip is approved, a strike-off on the actual greige fabric Rowad Knits knitted for this order. Only after both are approved does the full dye lot run.
The worked numberColorline Dyeing's fixed dye-lot minimum is 300 kilograms (docs/02 section 6). A lab dip and a strike-off are both a small fraction of that: a lab dip is typically well under one kilogram of yarn or fabric, and a strike-off, while larger than a lab dip, is still far short of the 300-kilogram minimum a bulk dye lot requires. The lesson's worked output is not a new figure but the comparison itself: two cheap, small-scale checks stand between a colour standard and a 300-kilogram commitment.
A common mistake is treating an approved lab dip as proof enough to run the full dye lot, skipping the strike-off step entirely. A lab dip and the actual bulk fabric can behave differently under the same dye recipe, because of differences in fibre preparation and absorbency between the small lab sample and the real production substrate. A lab-dip match alone does not guarantee the bulk fabric will match too. Skipping the strike-off risks discovering a colour mismatch only after the full, often 300-kilogram-or-larger dye lot has already run.
A mill dyes a small sample first, in its own lab, to see how close it can get to the colour a buyer wants. If that small sample is approved, the mill then dyes a larger sample on the real fabric the full order will use, to check the colour still holds. Only after both small samples are approved does the mill dye the full, often much larger, batch. Skipping the second sample because the first one already matched is a mistake: a small lab sample and the real fabric can take the same dye differently, so approving one does not prove the other is right.
Cedar & Co.'s colour standard for its domestic Make to Stock order has already been approved as a lab dip. Colorline Dyeing's dyeing manager, keen to keep the schedule moving, sends the merchandiser the following message.
You are the merchandiser handling this order. Should the full dye lot proceed now? Decide before opening the answer.
No — a strike-off on the actual bulk fabric should be produced and approved first. Two facts decide this together.
First, the lab dip and the bulk fabric are different substrates. The lab dip was dyed on a small lab sample; the bulk fabric Rowad Knits knitted for this order may take the same dye recipe differently, because of differences in fibre preparation and absorbency. An approved lab dip proves the recipe can reach the right colour on a lab sample. It does not prove the recipe reaches the right colour on the real production fabric.
Second, the cost of being wrong is much larger at bulk scale. The strike-off itself is a small, low-cost check. Running the full 300 kg dye lot directly, without that check, risks discovering a mismatch only after the whole batch is dyed — a batch many times larger than either approval sample, and one Cedar & Co. cannot sell if the colour is wrong.
Both facts point the same way: approve a strike-off on the actual bulk fabric first, and release the full dye lot only once that strike-off is approved.
This lesson's cost is framed by comparison, not by a new invented figure. A lab dip and a strike-off are both a small fraction of Colorline Dyeing's fixed 300-kilogram dye-lot minimum (docs/02 section 6); the mill spends little material and little time confirming the colour at each of these two small stages. Skipping the strike-off and going straight from an approved lab dip to the full dye lot risks a mismatched colour discovered only after the whole 300-kilogram-or-larger batch has been dyed. Cedar & Co. cannot put a wrong-coloured T-shirt on 12 shop shelves it stocks from its own forecast, so a mismatched bulk dye lot is not a discount item; it is fabric the mill and the factory must explain, re-dye, or absorb as a loss, against an order whose profit depended on getting the colour right the first time.
Use the colour approval tracker (`templates/T04-C03-colour-approval-tracker.xlsx`, download link on this course's page) to log this lesson's stages: each row's date submitted, date decided, and status (Submitted, In review, Approved, Conditional, or Rejected).
| Approval stage | Date submitted | Date decided | Status |
|---|---|---|---|
| Lab dip (Cedar & Co.'s colour standard) | your order's date | your order's date | your order's status |
| Strike-off (bulk fabric sample) | your order's date | your order's date | your order's status |
| Bulk dyeing sign-off | your order's date | your order's date | your order's status |
Never mark "Bulk dyeing sign-off" before both rows above it show "Approved".
1. What is a lab dip?
2. What is a strike-off, and how does it differ from a lab dip?
3. A mill has approved a lab dip for a 500-kilogram export order's colour. Should the full dye lot proceed now, without a strike-off?
| EN | AR | FR | TR | Meaning |
|---|---|---|---|---|
| Colour standard | معيار اللون | Étalon de couleur | Renk standardı | The reference colour a buyer sets and communicates to a mill, against which every lab dip and bulk dyeing is checked. |
| Lab dip | عينة مختبر (لاب ديب) | Lab dip | Lab dip | A small dyed sample, often yarn or a small fabric swatch, a mill produces in its lab to show how close it can get to a colour standard, before committing to a full dye lot. |
| Strike-off | الطبعة التجريبية (سترايك أوف) | Strike-off | Strike-off (deneme baskısı) | A larger sample, produced on the actual bulk fabric rather than a lab sample, confirming the colour holds on the real production substrate. |
| Dye lot | دفعة الصباغة | Lot de teinture | Boya partisi | One batch of fabric dyed together in the same vat, which can differ slightly in shade or hand-feel from another batch of the same colour. |
| Dye-lot minimum | الحد الأدنى لدفعة الصباغة | Minimum de lot de teinture | Boya partisi minimumu | The smallest quantity a mill will run as one dye batch. |
You now know why a lab dip and a strike-off are approved in sequence before a full dye lot runs. The next lesson looks at what happens when an approval is conditional rather than a clean yes or no. Back to the course map