A lab dip is a small piece of your actual fabric, dyed by the mill to a specified colour and sent to you for approval before bulk production starts. You check it under daylight and under a light box, sign it off, and the mill dyes the bulk to that approved standard. It typically takes five to seven working days and two rounds. Without one, you are not choosing a colour — you are guessing at one.
Most colour problems start before production, in the gap between a digital reference and a piece of dyed cotton. A Pantone number defines a target, but it does not tell you how that target behaves on a 380GSM brushed fleece versus a 180GSM single jersey. Cotton absorbs dye differently depending on yarn count, twist and surface finish, and every screen renders the same hex value slightly differently.
A lab dip closes that gap. It is the only point in the process where colour is both physical and cheap to change. Once bulk fabric is dyed, changing the shade means re-dyeing or remaking — and on a 500-piece order, that is a season, not a delay.
Buyers often use these three words interchangeably, which causes real confusion in the approval thread. They approve different things at different stages.
| Stage | What you are approving | Typical lead time | What it cannot tell you |
|---|---|---|---|
| Lab dip | Colour, dyed on the actual fabric you ordered | 5–7 working days | Print detail, hand feel, final garment shape |
| Strike-off | Artwork and print quality on fabric | 7–10 working days | Whether the bulk dye lot will match the dip |
| Bulk | Finished production | 25–35 days after approvals | Nothing — after this stage, colour changes mean remakes |
Two rounds is standard. Three is not unusual on saturated shades — navy, black, deep red and olive are the hardest to land because small pigment changes read as large visual shifts. Beyond three rounds, the cause is usually structural rather than a matter of tweaking: the reference may be a different substrate, the standard may be a screen colour rather than a dyed one, or the mill may be dyeing a fibre blend it cannot match exactly.
Each round costs five to seven days plus courier time. If your delivery date is fixed, plan three weeks for colour approval alone on a new shade, not one.
1. Metamerism. Two colours can match perfectly under one light source and diverge under another. A shade approved in a north-facing office may look greener under retail fluorescent. If the garment will be sold under store lighting, approve the dip under that lighting too.
2. Substrate. The same Pantone code on loopback fleece, single jersey and rib reads as three different colours, because pile and surface reflection change how light leaves the fabric. This is why the dip must be made on the ordered fabric.
3. Dye lot. Yarn from a different lot takes up dye differently. Ask whether your bulk yarn is booked at the time of dip approval; if it is not, the dip you approved may not correspond to the fabric that actually gets dyed.
4. Finishing. Brushing, enzyme softening, mineral wash and acid wash all shift tone. Acid wash in particular lifts and mutes colour unevenly by design. On washed styles, approve a washed dip — approving a greige dip and washing later is a reliable way to end up with a shade nobody signed off on.
On our custom sweatshirt production, a new shade goes through two dips on the ordered fleece, reviewed under D65 and TL84, before bulk yarn is booked. The three colourways on our 380GSM quarter-zip sweatshirt — oatmeal, washed black and sage — were approved this way, and the washed black in particular exists because the greige dip and the washed result were two visibly different colours.
For lighter jersey styles the same rule applies with a different substrate; the dips on our blank t-shirt range are made on single jersey rather than fleece, because a dip made on fleece would tell you nothing useful. Heavier brushed styles such as our custom hoodies need the wash stage included in the approval, for the reason described above.
Q1: How long does a lab dip take?
A: Five to seven working days for dyeing, plus courier time. On a new shade with no existing reference, plan three weeks including two rounds and shipping.
Q2: Can I approve a colour from a photo?
A: No. Cameras, compression and screens all shift colour, and the shift is largest in exactly the shades buyers care about — navy, olive and black. Use a physical dip, or a live video call under a light box if shipping is too slow.
Q3: Do I have to pay for lab dips?
A: Dips are usually charged per colour and per round, and are commonly credited against the bulk order if it proceeds. Confirm the policy with your supplier before you request six colours.
Q4: I only have a photo of the colour I want. Is that enough?
A: It is a starting point, not a specification. Send the photo plus any physical reference you can find, and expect the mill to propose the nearest TCX match for you to approve on fabric.
Q5: Can you match an existing garment I already sell?
A: Yes, provided the fabric substrate is the same or close. If your existing piece is a 180GSM jersey and the new style is a 380GSM fleece, the same dye will read differently and we will tell you so before dyeing.
Q6: Does acid wash or mineral wash change the approved colour?
A: Always. Washing lifts colour and softens contrast, and the effect varies across the garment by design. Approve a washed dip, not a greige one, or the bulk will not match what you signed.
Send your Pantone reference, fabric weight and target delivery date, and we will come back with two dips on the correct substrate, a light-source note and a production slot. If you are still deciding between shades, our team can advise which ones survive washing and which ones shift. Contact us here and we will reply within 12 hours.
