How Do You Handle a Blank Lot Change Mid-Run?

A blank lot change mid-run is a supply event that turns into a customer event unless somebody tests it first. The new carton looks identical on the outside, but the shade, the hand feel and the residual shrinkage can all move at once, and a print applied to the new blank may read differently from the same print on the old one. The question is not whether variance exists, because it always does. The question is which variance a buyer will notice, which variance a print step can absorb, and which variance has to be disclosed before the run continues. This guide sets out the three variables a lot change moves, the tests that separate them, and the point at which continuing the run costs more than pausing it.

Key Takeaways

• A lot change moves three things independently: shade, hand feel and residual shrinkage.
• Test the new lot against a retained sample from the old lot, not against a colour card.
• Print the same artwork on both lots before releasing the balance of the run.
• Disclose a mid-run switch when the garment is sold as a set, a uniform or a repeat order.
• Pause when shade separation is visible in daylight, not when a lab reading differs.

What a Blank Lot Change Moves

Three variables matter, and they fail in different ways. Shade variation is the one buyers see first, because two garments worn together in daylight read as a pair. Hand feel is the one buyers describe as "different" without being able to name it. Residual shrinkage is the one that generates a complaint two weeks later, when a garment that fitted on arrival does not fit after the first wash.

A single lot change can move all three, and the movement is not always in the same direction. A new lot can be slightly lighter and slightly softer, or slightly darker and slightly heavier. Treating the three as one variable leads to a test that measures only shade and then declares the lot acceptable.

There is a fourth variable that matters for print rather than for the garment: surface. What we see when switching blank suppliers mid-season repeats here: a different lot of the same cotton style can take pre-treatment differently, and a DTF transfer that released cleanly on the previous lot can show a duller edge on the new one. That difference is invisible until the print is on the garment.

The Three Variables and How Each One Shows Up

Notice that three of the four tests require a physical comparison against the previous lot. A colour card tells you what a shade should be. A retained sample tells you what the last hundred garments looked like, which is the only reference the buyer has.

Keeping a sealed garment from each accepted lot solves most of this. It costs one unit per lot and it turns a subjective conversation into a physical one. When a buyer says the new batch looks different, the sample answers the question before anyone argues.

What to Test Before Releasing the Balance

The sequence matters more than the equipment. Start with shade, because it is the fastest to judge and the most likely to stop the run. Put one new garment beside one from the retained sample in daylight, folded the same way, and step back. If the difference is visible at conversational distance, that is the answer, and no instrument reading changes it.

Move to print next. Run the live artwork on the new lot with the settings already approved for the old lot. Compare the two prints side by side: edge definition, colour saturation and how the film released. A print that looks slightly flat on the new surface will not improve after a hundred more units.

Finish with a wash test on one garment from each lot. Measure the chest width and body length before and after, using the same points, and compare the two deltas rather than the two absolutes. The useful number is how much more the new lot moves than the old one, because that difference is what a repeat customer experiences.

On our production floor we run this sequence on the first carton of any new lot, before the carton is broken into the picking flow. Our qc team keeps one sealed garment per accepted lot for exactly this comparison, which is why a shade question can usually be answered with a photograph rather than a reprint.

When to Pause the Run

Pause when the shade difference is visible side by side in daylight. Pause when the new lot's print release needs a different press setting, because that means the old setting is no longer validated. Pause when the wash delta moves enough that a stated size would no longer hold after the first wash.

Do not pause for a difference that only appears under a colour instrument. A measured delta with no visible separation produces a hold, a conversation and a delayed order, and the buyer's customer never sees the problem that caused it. The judgement standard should be the one the end user applies: two garments, daylight, side by side.

There is a middle case worth planning for. When the new lot is acceptable on its own but separable from the old lot, the right move is often to finish the current run on the old lot and start the next run on the new one, rather than mixing both inside a single order. That keeps every individual order internally consistent, which is what a buyer experiences in practice.

What to Tell the Buyer

Disclosure depends on how the garment is sold. A single one-off purchase rarely needs a lot note, because the customer has no second garment to compare against. A set, a uniform, a team order or a repeat programme does, because the comparison is built into how the product is used.

Write the note in plain terms: the lot changed, the shade sits within the range we accept, the print was re-verified on the new lot, and the wash behaviour was checked against the previous lot. Avoid framing it as a defect, because it is not one, and keep the merch vendor handoff in the same note. Frame it as a supply fact the buyer can pass on if their own customer asks.

For a repeat programme, offer the choice rather than making it. Some buyers would rather wait for the previous lot to return than accept a shade shift in a product their customers reorder. Others would rather ship now. Both are reasonable, and the decision belongs to the party that owns the customer relationship.

Limits: Where Lot Control Does Not Work

Lot control does not work when the blank is bought through a channel that cannot tell you the lot. If the supplier ships from mixed stock without lot identification, there is nothing to compare and nothing to disclose. In that situation the only reliable control is to buy the full quantity for a run in one purchase, so the run is internally consistent by construction.

It also fails when the run is too small to justify the test. A ten-piece order does not carry a wash test and a print comparison per lot. For small runs, the practical answer is to accept the variance, buy from one carton, and keep the disclosure generic rather than per-lot.

A third limit is fibre blend. A tri-blend or a heather moves more between lots than a solid cotton, and the movement is harder to describe because the appearance depends on how the fibres happened to fall. For those styles, set expectations on the range rather than on a fixed shade, and treat heather variation as a characteristic of the product rather than a deviation from it.

Finally, lot control does not replace a specification. If the purchase order does not state a fibre content, a fabric weight and a shade reference, a lot change cannot be judged against anything. The spec is what makes the comparison meaningful.

How Lot Changes Interact With Print Settings

A press setting is validated against a surface, not against a product name. When the surface changes, the setting is an assumption. That is why a lot change should trigger a single test print even when the blank is nominally the same style and the same colour.

The variables that move first are pressure and dwell. A slightly denser lot may need a little more of both to reach the same release, and a lot with a different pre-treatment uptake may need less. The test print tells you which direction to move without guessing on a live order.

Keep the approved test print with the lot record. When a question arrives three weeks later about a specific batch, the print and the garment sample answer it together, and the answer is evidence rather than recollection.

Frequently Asked Questions

Is a blank lot change the same as a shade variation defect?

No. A lot change is a supply event and is expected. A defect is a garment outside the accepted range. The test decides which one you are dealing with, and the answer changes whether the run continues or the lot is rejected.

How many garments should I keep from each lot?

One sealed unit per accepted lot is enough for shade and hand comparison. Keep a second unit if you intend to wash test, because the wash destroys the sample's value as a reference.

Should I mix two lots inside one order?

Avoid it. An order that contains both lots puts the comparison in the customer's hands. Finish one lot before starting the next, even if that means holding a few units for a day.

What if the supplier cannot identify lots at all?

Then treat every delivery as a possible lot change. Buy the full quantity for a run in one purchase, test the first carton, and disclose the range rather than a specific shade.

Does a lot change affect embroidery as well as print?

Yes. A denser lot changes how a stitch sits and how much the fabric pulls around a dense design. The same test logic applies: run the live design on both lots before releasing the balance.

How long should a retained sample be kept?

Keep it for as long as the style is on sale and for one reorder cycle after that. A sample that outlives the product tells you nothing about the order in front of you.

The Short Version

A blank lot change is manageable when it is treated as three separate questions about shade, hand and shrinkage rather than one vague concern. Keep a sealed garment per lot, compare in daylight, print the live artwork on both surfaces, and wash one unit from each. Pause when the difference is visible to a buyer and continue when it is not. Disclose the change wherever the product is used as a set or a repeat, and treat the blank lot change as a supply fact to be documented rather than a defect to be argued about.

Related Articles

Which Companies Handle T-Shirt Dropshipping?

Which Shopify Apps Handle Print on Demand Orders?

How Does Custom Product Printing Change a Business?