Production & quality
Lab dip approval: how colour matching works for apparel
A lab dip is a small swatch of your fabric dyed to match a colour standard, such as a Pantone TCX reference. The dye house usually sends several options. You pick one under an agreed light source, and that approved dip becomes the colour standard for bulk dyeing and for the PP sample.
Key takeaways
- Always give a physical colour standard, either a Pantone TCX chip or a fabric swatch. A screen colour on its own is not enough.
- Approve colour under an agreed light source, commonly D65 daylight, and check for metamerism under a second one.
- Lab dips are matched on your actual fabric, because fibre and structure change how a colour looks.
- The approved dip is the reference for bulk, and shade is checked roll to roll before cutting.
Colour is one of the most common reasons apparel gets rejected. The lab dip process settles colour on a small swatch, under controlled conditions, before any bulk fabric goes into the dye machine.
1. What a lab dip is
A lab dip is a swatch of the order’s own fabric, dyed in the laboratory to match a colour standard. The dye house works out a recipe, dyes a few options and sends them for approval. They are usually labelled A, B and C, each a slightly different reading of the target. Once you approve one, the dip and its recipe become the standard for the bulk dye lot.
2. Colour standards
| Standard | Notes |
|---|---|
| Pantone TCX (cotton) | Common physical reference for apparel on cotton |
| Pantone TPX / TPG (paper) | Usable, but paper reflects light differently from fabric |
| Your own fabric or garment swatch | Clear target, especially for repeating an existing colour |
| Previous approved lab dip | Best for repeat orders |
| Digital colour (RGB, hex, screen) | Not a reliable standard on its own |
Send the physical standard to the factory and keep an identical one yourself, so both sides compare against the same object.
3. Light sources and metamerism
Two colours can match under one light and differ under another. That is metamerism. To control it, agree a primary light source (D65 artificial daylight is widely used) and check under a secondary one, such as TL84 store lighting or incandescent (A). Use a light box, not a window or office lighting, and view at a consistent angle against a neutral background.
4. How the process works
- The buyer sends the colour standard, fabric specification and light source.
- The dye house dyes options on the actual fabric, and on rib if rib is used.
- The factory submits the dips, labelled and dated.
- The buyer approves one, or comments and asks for a resubmission.
- The approved dip is signed and kept by both sides, then used for bulk.
- Bulk is dyed and checked against the dip roll by roll.
For knitwear, ask for the body fabric and the rib to be dipped together. Rib and flat-knit collars use different structures and can look different from the body even on the same recipe.
5. How to comment on a lab dip
Say which direction to move, not just “not right”.
| Comment | What it means |
|---|---|
| Too red / too yellow / too blue / too green | Hue needs to shift |
| Too dark / too light | Depth needs adjusting |
| Too dull / too bright | Saturation (chroma) needs adjusting |
| “B is closest, make slightly lighter” | Clear starting point for the next round |
Many brands also use a spectrophotometer and a colour difference value (such as Delta E with CMC tolerancing) next to the visual check. If you approve by instrument, agree the method and tolerance in writing. Visual approval under the light box is still the usual final check.
6. From lab dip to bulk
A lab dip is dyed in a small machine and bulk in production machines. Small shade differences between lab and bulk, and between bulk lots, are normal, and they have to be controlled. Before cutting we compare bulk shade with the approved dip, and we check shade roll to roll during fabric inspection. Panels for one garment are cut from the same roll so there is no shade difference within a garment, and rib, collar and body are checked together. If more than one lot is used, shade bands or a shade report should be shared. The PP sample is then made in bulk fabric; see garment sampling stages.
At Jehotex, fabric is inspected on the 4-point system and shade is checked roll to roll before cutting. See our production process and quality control pages.
7. Colour fastness is a separate check
Matching a colour does not mean it will stay put. Fastness to washing, rubbing (crocking) and light is tested separately, and dark and bright shades on cotton deserve particular attention. State the tests and requirements you need in your tech pack.
Final thoughts
Lab dips work when both sides look at the same physical standard, on the same fabric, under the same light. Give a Pantone TCX chip or swatch, name the light source, dip the rib with the body, comment in clear directions, and keep the signed dip as the bulk reference. Colour arguments after production cost a lot, and a careful lab dip round costs very little. Ready to start? See our OEM/ODM page.